Mini 3 - Neuro Flashcards
1
Q
Describe the posterior cerebral artery.
A
Big, supplies the medial and inferior surfaces of the occipital and temporal lobes, sends branches to rostral midbrain and caudal diencephalon, gives rise to posterior choroidal arteries (supply choroid plexus of 3rd and lateral ventricle).
2
Q
Where is the accessory nucleus?
A
Spinal cord.
3
Q
What is the difference betwen aknesia and dyskinesia?
A
Absence/poor movement vs fragmentary/incomplete movement.
4
Q
What do you get if you knock out the left hemisphere (in most people)?
A
Minimal right neglect.
5
Q
Describe the pathway for spoken and written language.
A
Auditory cortex or visual (then auditory) cortex. Then Wernicke’s area, the Broca’s via arcuate fibers. Then primary motor cortex.
6
Q
What is syringomyelia?
A
Enlargement of the central spinal cord. Usually causes ‘cape-like’ loss of pain and temperature by the C5 dermatome, but really it can be anything depending on the lesion.
7
Q
What does layer IV of the neocortex do?
A
Gets input from the thalamus.
8
Q
What are stellate cells excitatory/inhibitory on?
A
Inhibitory on Purkinje dendrites.
9
Q
What kind of drugs are gabapentin and pregabalin, how does it work and what kind of pain does it treat?
A
Structural analogues of GABA but no effect on GABA receptors! THey inhibit presynaptic N, L, P/Q type VG Ca++ channels containing alpha2delta subunits. Treat neuropathic pain, also epilepsy. Gabapentin can also treat postherpathic neuralgia, pregabalin ca also treat pain associated with diabetic peropheral neuropathy, SC injury,fibromyalgia, or also postherpertic neuralgia.
10
Q
What is the pain threshold of sound?
A
120dB. 150 can rupture the tympanic membrane.
11
Q
What are the second order neurons in the olfactory epithelium? And what tracts do they form and where do they project to?
A
Mitral cells (form lateral olfactory tract) and synapse with the primary olfactory cortex. Tufted cells (form medial olfactory tract) projects bilaterally to the basal forebrain.
12
Q
How is interaural intensity difference processed?
A
By the lateral superior olive. Signal goes to the ipsilateral LSO and then to the contralateral medial nucleus of the trapezoid body (sends inhibitory signals to its own LSO).
13
Q
What are the lobes of the cerebellum?
A
Anterior, posterior, flocculonodular. There is also the vermis down the midline.
14
Q
What is the spinomesencephalic tract?
A
Spinothalamic but it synapses at the end at the periaqueductal gray.
15
Q
How are salty and sour tastes received?
A
Na+ through ion channel and H+ through ion channel.
16
Q
What type of neurotransmission does Haloperidol work on and how?
A
Dopaminergic. D2 antagonist.
17
Q
Describe saccades.
A
FEF initiates saccades - talks to ipsilateral superior colliculus, talks to contralateral PPRF, which talks to CN VI. CN VI talks to the ipsilateral lateral rectus and the contralateral CN III (medial rectus) via MLF.
18
Q
What does the Suprachiasmatic nucleus do?
A
Projects indirectly to the pineal gland and controls its synthesis of melatonin.
19
Q
What is in the posterior area of the hypothalamus?
A
Mammillary bodies (learning and memory), Posterior nucleus (thermoregulatory, conserves heat), Tuberomammillary nucleus (histaminergic, important in wakefulness and arousal).
20
Q
What syndromes can come from occlusion of the posterior cerebral artery?
A
Superior alternating / Weber’s / Medial midbrain. Affects CN III and corticospinal axons - can cause alternating hemiplegia. Also Benedikt’s syndrome - same as Weber’s plus ataxia (tegmental regions of midbrain also affected).
21
Q
What does lack of sleep predispose someone to?
A
Viral infections, weight gain, diabetes, high BP, heart disease, mental illness, mortality.
22
Q
Where is the mesencephalic nucleus?
A
The midbrain to the upper pons.
23
Q
What is Meniere’s disease?
A
Attack of rotational vertigo, unilateral/bilateral hearnig loss, tinnitus, pressure in both ears.
24
Q
Describe the basal ganglia indirect pathway.
A
Cortex excites striatum, inhibits GPe, inhibits STN, excites GPi, inhibits thalamus, excites cortex. Net inhibition to cortex.
25
What's the difference between drug misuse and drug abuse?
Use for medicinal purposes but wrong vs use for non-medicinal purposes.
26
What are commissural fibers? What are the different types?
Primarily I-III layers, interconnect homologous areas of two hemispheres. Corpus callusum, anterior commissure, posterior commissure.
27
Which neurotransmitter receptors mediate most of the fast excitatory neurotransmission in the CNS?
Glutamatergic.
28
What is the Limbic cortex loop?
Limbic cortex to nucleus accumbens to ventral globus pallidus to Dorsomedial nucleus of the Thalamus.
29
Where are the Cochlear nuclei?
Mid-medulla.
30
What does layer V of the neocortex do?
Outputs to striatum, brainstem, and spinal cord.
31
What are the reflex grades?
2+ is normal, 1+ is hypoactive, 0 is absent, 3+ is hyperactive without clonus, 4+ is hyperactive with clonus.
32
What type of neurotransmission does Nitrous oxide work on and how?
Glutamatergic. NMDA antagonist.
33
What are layers 3-6 from the LGN?
Parvocellular layers - deal with colour and form - midget ganglion cells.
34
Which visual pathways identify 'what' and 'where'?
From the virual cortex, the dorsal path identifies 'where' and the ventral path 'what'.
35
What is the Thalamus made up of?
A, M, L lobes divided by internal medullary lamina. 2 halves of the thalamus connected by massa intermedia.
Anterior lobe - anterior nucleus
Medial lobe - dorsomedial nucleus
Lateral zone - VA, VL, VPM, VPL ventrally; Pulvinar, lateral posterior, lateral dorsal dorsally
Also LGN and MGN
36
What type of neurotransmission does Sumatiptan work on and how?
Serotonergic. 5HT1 B/D agonist.
37
Where is the olfactory association cortex?
The orbital gyri of the prefrontal cortex.
38
How is ACh made?
Choline (nitrogen-containing alcohol) acetylated via choline acetyltransferase.
39
What is a MEG?
Magnetic encephalogram. Records miniscule magnetic signals made by neural activity, better localization of activity than EEG.
40
What type of receptor is the beta1 receptor, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Responds to adrenaline. Metabotropic. Increase of cAMP, decrease in K+ conductance. Excitatory.
41
What is the Rinne Test?
Compares air vs bone conduction. Normal is AC\>BC. Conductive loss is BC\>AC, sensorineural loss is AC\>AC but both decreased.
42
What are golgi cells excitatory/inhibitory on?
Inhibitory on mossy fibers.
43
What does the vestibulospinal tract do?
Lateral facilitates alpha and gamma motor neurons that facilitate extensors, maintaining posture. Medial causes rotation/lifting of head as well as rotation in the scapula.
44
What is the cause of Parkinson's? Describe it. How do you treat it?
SNc degeneration (degeneration of nigrastriatal pathway). Hypokinetic, tremor, rigidity, etc. Symptoms present at 90% neuron loss. Give Levodopa and Carbidopa, D2 agonists, selective MAO-B inhibitors.
45
What are the derivatives of the diencephalon?
Thalamus, hypothalamus, epithalamus, pituitary, pineal, optic vesicle. Also third ventricle.
46
Where is the main input of the vestibulocerebellum and what deep cerebellar nucleus does it work with?
Main input semicircular canals and vestibular nuclei, works with fastigial.
47
Where is a lumbar puncture done?
L3/L4 in adults, L4/L5 in children.
48
Describe Merkel's discs.
Superficial, slowly adapting. Allow for 2pt discrimination.
49
What's the only cranial nerve nucleus that innervates the opposite side.
The trochlear nucleus.
50
What is drug tolerance and what are the types?
Decreasing body response to the action of a drug that usually results from prior exposure. Pharmacokinetic tolerance is due to the decrease of the effective concentration at the site of action. Pharmacodynamic tolerance is due to homeostatic adaptive changes that counteract the drug effect, changes in number or properties of the receptor.
51
What's special about frontal lobe lesions?
They can cause contradictory symptoms in different people. Frontal lobe deals with restraint, initiative, order.
52
Where do signals go from the dentate nucleus?
Through the SCP, across the midline, synapses on the VL of the thalamus.
53
What does the Romberg Test test?
Dorsal column proprioception NOT cerebellar function. Person with damage sways with closed eyes.
54
What is dysdiadocokinesia?
Impairment of the ability to perform rapid alternating movements.
55
How many spinal cord injuries is alcohol involved in?
25%.
56
What are Betz cells?
Specialized layer V neocortex pyramidal cells.
57
Describe N3 of non-REM sleep.
Delta waves on EEG. Parasomnias (night terrors, bed wetting, somnambulism, somniloquy).
58
What are basket cells excitatory/inhibitory on?
Inhibitory on Purkinje soma.
59
Which phases of sleep predominate at what point?
First 1/3 N3, last 1/3 REM predominates. In infants REM is like 50% of sleep, at about 80 y/o the REM reduces.
60
What is alexia without agraphia?
Lesion in dominant occipital cortex prevents visual processing from right hemifield (right hemianopia).
61
Describe Ruffini endings.
Deep, slowly adapting. Respond to slide of skin against skin.
62
Where do the ampullae of the semicircular canals project to?
SVN and rostral MVN.
63
Describe an epidural hematoma.
Lens shape, bounded by sutures, can cross midbrain. Caused by the meningeal artery or dural venous sinus.
64
What kind of drug is amitryptilline, how does it work and what kind of pain does it treat?
A tricyclic antidepressant (1st gen). Blocks uptake of serotonin and NorE. Treats neuropathic pain (fast action) - and also major depressive disorder.
65
What are the exceptions of the corticobulbar tract?
It's generally bilateral innervation with contralateral dominance except for CN VII (ventral nucleus only contralateral), CN XI (only ipsilateral), CN XII (only contralateral).
66
What hormones peak in what states of consciousness?
Growth hormone and melatonin in sleep (though at different times), and cortisol in waking.
67
What is Parinaud's syndrome?
Lesion of dorsal midbrain and pretectal area. Loss of vertical gaze, dilated and irregular pupils with Argyll pupils. Collier's sign (upper eyelid retraction) and convergence retraction nystagmus.
68
What does the reticulospinal tract do?
Lateral inhibits voluntary or cortically produced movements, medial facilitates them. Both act on gamma motor neurons. Fibers contribute to spasticity in patients with corticospinal damage or to tonic extension of extremities in patients with decerebrate rigidity.
69
What is Brown-Sequard syndrome?
1/2 spinal cord lesion - lose ipsilateral touch and motor, contralateral pain and temperature.
70
Where is the organ or Corti?
In the cochlea.
71
What do layers I-III of the neocortex do?
Receive input from cortex and outputs to other areas of the cortex.
72
Where does the cuneocerebellar pathway get info from?
Upper limb and neck.
73
What kinds of drugs are Aspirin (acetylsalicylic acid) and Ibuprofen? How do they work?
NSAIDs. Inhibit COX1 and COX2 (convert arachidonic acid to prostaglandins). Aspirin is irreversible, ibuprofen is competitive.
74
What is internuclear ophthalmoplegia?
MLF syndrome. Lesion between CN VI and III. Knocks out ipsilateral adduction. Convergence is intact.
75
Where do the microglia derive from embryologically?
Not neuroectoderm! Mesenchyme.
76
Describe the periaqueductal gray raphe nuclei tract / raphespinal tract.
Gets info from the limbic system, starts from PAG, synapses in the medullary nucleus raphe magnus. Then synapses at a Lamina II interneuron. Lamina II neuron inhibits Lamina V spinothalamic neurons and suppresses pain.
77
What is decerebrate rigidity?
All extensors rigid, red nucleus influence removed. Medial rubrospinal and lateral vestibulospinal the cause. Reticulospinal involged.
78
What does the anterior commissure connect?
Olfactory nuclei, amugdala, anterior temporal lobes.
79
What is an aneurysm?
Swellings of the arterial wall (usually at the bifurcation) - can compress brain structures.
80
Where is the facial nucleus?
The lower pons.
81
What is agnosmia?
Loss of verbal ability to classify/identify odours.
82
What ganglia from the taste cranial nerves are involved in synapsing to the nucleus solitatius?
VII - geniculate IX - petrosal X - nodose
83
What is the cause of Hemiballismus? Describe it.
Damage to the contralateral STN. Hyperkinetic. Sudden, wild flailing of one arm +/- ipsilateral leg.
84
What is the FEF Brodmann number?
8
85
What modalities does CN X transmit and what nuclei are they associated with?
All 5! BE (Nucleus ambiguus). GVE (Dorsal motor nucleus of X). SVA&GVA (Nucleus solitarius). GSA (Main sensory and spinal nucleus of V).
86
Where is the Subthalamus and what is it made up of?
Inferior to thalamus, lateral to hypothalamus, medial to internal capsule and cerebral peduncles. STN, Substantia Nigra, Red Nucleus, Zona Incerta.
87
How do you tell AICA from PICA occlusion?
Nucleus ambiguus/solitarius only affected in PICA (taste issues). Motor/sensory nucleus of V and facial nucleus only affected in AICA (jaw deviation, face issues).
88
Where does the anterior spinocerebellar pathway get info from?
Distal lower limb, transmits muscle spindle and golgi tendon organ afferent info.
89
When is the highest incidence of a DVT complication of spinal cord?
72hrs-14 days after.
90
What are the layers of the neocortex?
I (molecular), II (external granular), III (external pyramidal), IV (internal granular), V (internal pyramidal), VI (polymorphous).
91
What is Lateral medullary syndrome and what is another name for it?
Wallenberg's syndrome. Occlusion of the PICA. Affects spinothalamic, descending tract of V, inferior cerebellar peduncle, descending sympathetic fibers (Horner's syndrome), cochlear nuclei, nucleus solitarius, nucleus ambiguus.
92
What is the production of new neurons and the destruction of neurons called?
Neurogenesis and neurodegeneration.
93
How does Lidocaine work?
Blocks inactivated VG Na+ channels.
94
What is the dominant hemisphere for language?
Left usually (90% of right handed and 70% of left handed people). Left handed people also often have some bilateral.
95
What is reelin? What do mutations in it result in?
An ECM protein needed for neuronal migration termination. It's secreted by early born neurons 'Cajal-Retzius cells'. A mutation in it causes Norman-Roberts syndrome - inverted cervical lamination, cerebellum underdevelopment, cranio-facial abnormalities. LIS2 lissencephaly.
96
What are the types of apraxia?
Ideomotor (can't do an imaginary action), Ideational/conceptual (inability to conceptualize and complete multi-step task or voluntarily perform learned task). Constructional (inability to copy drawings).
97
What type of receptor is the beta2 receptor, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Responds to adrenaline. Metabotropic. Increase of cAMP. Inhibitory.
98
When does neurulation occur?
Week 3 and 4.
99
Where are the Vestibular nuclei?
Pons and upper medulla.
100
Describe the brain orienting axes.
Rostral/caudal is A/P axis. Dorsal is superior, ventral is inferior.
101
What arteries are connected in the circle of Willis?
Anterior cerebrals, internal carotids, posterior cerebrals.
102
What type of neurotransmission does Benztropine work on and how?
Cholinergic. M1 antagonist.
103
Where do the maculae of the semicircular canals project to?
Terminate in LVN, saccular macula also projects to IVN.
104
Describe the posterior spinocerebellar pathway.
DRG via fasciculus gracilis, to Clarke's nucleus. Travel via distal spinocerebellar tract in lateral funiculus through inferior cerebellar peduncle into cerebellum.
105
What is the response in caloric testing for a bilateral MLF lesion?
No adduction, only abduction. Moves towards cold water and away from warm.
106
Where is the lumbar cistern?
From the conus medullaris to about S2.
107
What are the name of the ten sections the grey matter of the spinal cord can be divided into?
Rexed's Laminae, I being most dorsal.
108
Which of the meninges are vascular?
Dura mater (own blood supply) and also pia mater. Arachnoid mater is avascular.
109
Where is the superior salivatory nucleus?
Lower pons.
110
Describe the superior cerebellar artery.
Supplies the cerebellum and some midbrain. Separated from posterior cerebral by CN III.
111
What type of neurotransmission do Atropine and Scopolamine work on and how?
Cholinergic. Muscarinic antagonist.
112
What is Freidrich's ataxia?
Autosomal recessuve, hereditary, DC and lateral corticospinal degeneration.
113
What is subacute combined degeneration?
Lesions in the spinal cord due to a B12 deficiency, will affect DCML, lateral corticospinal tract. Spastic paralysis, hemiplegia.
114
Describe Broca's vs Wernicke's aphasia.
Broca's has stop/start speech, non fluent. Wernicke's is fluent but meaningless.
115
What is in the lateral area of the hypothalamus?
Lateral Nucleus - feeding center, regulates food intake (destructon=starvation), regulates drive states for pleasure and reward.
116
What kind of drugs are codeine and morphine, how do they work, and what effects do they have? (What kind of pain do they treat?)
Opioids (codeine is metabolized to morphine). They work at opioid - mu receptors. Presynaptically decrease Ca++ influx and postsynaptically increase K+ efflux. Analgesia, euphoria, miosis, constipation. (nociceptive).
117
What is the M-pathway?
The magnocellular layers will terminate on layer 4Calpha of the primary visual cortex.
118
What do the fasciculus gracilis and fasciculus cuneatus transmit?
Discriminative touch - gracilis T7 and below, cuneatus T6 and above.
119
What are the fibers in the genu of the internal capsule?
Corticobulbar, some thalamocortical fibers.
120
What part of the brain is REM elaborate visual imagery associated with?
PPRF (Paramedian pontine reticular formation).
121
What can result in a positive Babinski sign?
Being a baby, corticospinal tract damage, UMN damage.
122
What is the olfactory cortex's Brodmann number?
28, 34
123
What are the types of herniations following brain injury?
Cingulate (cingulate gyrus slips under falx cerebri and presses on other hemisphere). Usually inconsequential. Uncal (Uncus herniates through the tentorial notch and presses midbrain). Coma/death. Tonsilar (cerebellum presses on medulla through foramen magnum). Rapidly fatal.
124
What neurotransmitters do propiomelanocortin give rise to?
It's a peptide. Gives rise to endorphin, enkephalin, ACTH.
125
How many spinal arteries are there?
2 anterior and one posterior.
126
How do you treat conductive vs sensorineural hearing loss?
Conductive can be surgerized, sensorineural can be treated with a cochlear implant.
127
What are the types of glands in the outer ear?
Mixture of ceruminous (white) and sebaceous.
128
What kind of drug is capsaicin, how does it work, and what kind of pain does it treat? Also, how is it administered?
A local anaesthetic, agonist at the TRPV1 receptor. Treats nociceptive and neuropathic pain. Cream or liquid topically.
129
What muscle, nerve root, and nerve does the achilles/ankle jerk reflex test.
Gastrocnemius and soleus, S1, tibial n.
130
What sensation does the DCML pathway transmit?
Discriminative touch, mainly.
131
What is Kluver-Bucy syndrome?
Large bilateral amygdaloid lesions. Become placid, inappropriately sexual, agnosia, unable to associate stimuli with reward.
132
How does the trigeminal system work when it transmits fine touch, vibration, pressure, and proprioception?
1st cell body in the trigeminal ganglion travels via the trigeminal tract to the pons (main sensory nucleus of V or mesencephalic nucleus) and synapses. 2nd neuron crosses over in the pons and travels up the trigeminal lemniscus/trigeminal thalamic tract and synapses in the VPM. 3rd neuron synapses into the somatosensory cortex.
133
How does the trigeminal system work when it transmits pain?
1st cell body in the trigeminal ganglion travels down in the descending tract of V to the pons (spinal nucleus of V) and synapses. 2nd neuron crosses over in the pons and trvels up the trigeminal lemniscus/trigeminal thalamic tract and synapses in the VPM. 3rd neuron synapses into the somatosensory cortex.
134
Describe the CN VI palsy.
Horizontal diplopia, cannot abduct.
135
Where are the parasympathetic autonomic nuclei in the spine?
Intermediate zone, S2-S4.
136
Describe Meissner's Corpuscles.
Superficial, rapidly adapting. Sensitive to light touch.
137
What is the important part of the brain in long term potentiation?
Hippocampus. Quick high frequency EPSP that keeps the signal lasting for a long time.
138
What is the Brodmann's number for the primary motor cortex and where is it?
Precentral gyrus, 4.
139
Describe smooth pursuit.
FEF initiates ipsilateral smooth pursuit - talks to pontine nucleus which talks to flocculus of the cerebellum, which crosses to the contralateral vestibular nucleus.
Vestibular nucleus' contralateral CN VI is excited, ipsilateral one is inhibited. In a coma, can activate the vestibular nucleus by head rotations.
140
What is the paleospinothalamic / spinoreticular tract?
Sends memos to the reticular formation. Integrates emotion and motivation.
141
What causes truncal ataxia? How do they present?
Usually lesions to the vermie/flocculonodular lobe of the cerebellum. Present with 'drunk-like' gait in the Tandem Gait Test.
142
What is an Argyll-Robertson pupil?
Affected pupil doesn't constrict in response to light but does during accomodation.
143
When left to run freely, what is a person's circadian rhythm?
25h.
144
What are some factors associated with motor return after a spinal cord injury?
Initial grade of impairment at time of admission, pinprick sensation at initial examination, presence/absence of early motor return, motor function at 1 month after injury.
145
How many semicircular canals are there?
Three.
146
What are the derivatives of the telencephalon?
Cerebral hemispheres, olfactory tract/bulb, basal nuclei. Also lateral ventricles.
147
Describe the auditory pathway.
Cochlear nucleus talks bilaterally to both superior olivary nuclei. Superior olivary nucleus talks via the lateral lemniscus to the inferior colliculus, which goes to the MGN of the thalamus, and then the primary auditory cortex.
148
Where is the Edinger-Westphal nucleus?
In the upper midbrain.
149
What is the difference between the spine and brain dura?
Brain has 2 layers, spinal cord has one.
150
What type of receptor is 5HT2, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Responds to serotonin. Increases IP3/DAG and decreases K+ conductance. Excitatory.
151
What kind of drug is carbamazepine, how does it work and what kind of pain does it treat?
Anticonvulsant, blocks VG Na+ channels. Treats neuropathic pain, also epilepsy, can also treat bipolar disorder (also pain of V or IX neuralgia).
152
What are the primary vesicles of brain embryological development and when do they develop?
4th week. Prosencephalon, Mesencephalon, Rhombencephalon.
153
What kind of drug is ketamine and what kind of pain does it treat?
NMDA antagonist (non-competitive), and treats neuropathic pain. At higher doses can be an anaesthesia.
154
A lesion to the pons/PPRF causes which way eyes?
Wrong way eyes.
155
What kind of hemorrhage does a rupture of the cerebral artery or vein cause?
Subarachnoid, intraparenchymal, intraventricular.
156
Where does the tectospinal tract originate and decussate and terminate? Also, what does it do?
Originates in superior colliculus, decussates in midbrain, terminates in cervical spinal cord laminae VI-VIII. Function unknown but thought to produce postural changes in response to visual stimuli.
157
Describe the Papez circuit.
Important for storage of memory. Hippocampus to mammillary bodies to anterior nucleus of the thalamus to cingulate cortex. Sometimes singulate can project back to the hippocampus.
158
What is the stria of bennari?
4B visual cortex.
159
What kind of neurons are in the basal forebrain and what does it do?
Cholinergic. Determines the value/significance of memories/events.
160
What is drug dependence?
Any repeated use of a drug leading to an altered physiological state that requires continued exposure to prevent withdrawal syndromes.
161
What are the branches of the vertebral arteries?
Anterior and posterior spinal arteries, also PICA (posterior inferior cerebellar).
162
What is Adie's/Tonic pupil?
Affected pupil slow to constrict in both reflexes and slow to recover.
163
What modalities does CN II transmit?
SSA (vision).
164
How do you get quadrantanopia?
Injure the divisions of the optic tract or just the cuneus / lingual gyrus.
165
Describe CN IV palsy.
Vertical diplopia (improves when head tilted 'away', worsens with downward/nasal gaze).
166
What's the difference between somatic and visceral pain?
Somatic is localized, sharp, throbbing, visceral is diffuse, gnawing, cramping.
167
What is the Brodmann's number for the primary visual cortex and where is it?
Occipital lobe, 17.
168
What does a lesion of the optic chiasm cause?
Bitemporal hemianopia (loss of temporal visual fields).
169
Where is the main input of the pontocerebellum and what deep cerebellar nucleus does it work with?
Main inputs from sensory/motor cortices, works with dentate.
170
How does junctional transmission terminate?
Either enzymatic cleavage or diffusion away or dissipation of the transmitter via active reuptake into presynaptic neuron or active reuptake into associated structures like neuroglia.
171
What do Rexed's Laminae III, IV, V do and what are they called?
Nucleus proprius. Transmit mostly non-noxious stimuli however V can also do some noxious (wide dynamic range).
172
Where do signals go from the fastigial nucleus?
To the vestibular nucleus of the thalamus.
173
What connects the organ of corti to the basal lamina?
Spiral ligament.
174
What type of receptor is GABAa, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. GABA. Increases K+ conductance. Inhibitory.
175
How is interaural time delay processed?
By the medial superior olive in the superior olivary complex. Needs coincidental excitatory input.
176
What is the visual association cortex Brodmann number?
18, 19
177
Describe N1 of non-REM sleep.
Alpha waves to theta waves on EEG. Somnolence/drowsy sleep. Sudden nypnic jerks, hypnagogic hallucinations, loss of muscle tonie, loss of most conscious awareness of external environment.
178
Where is the conus medullaris?
L1/L2 in adults, L3 in children.
179
What does the Doll's Eye test?
VOR (brainstem) in a patient with a coma.
180
What is in the anterior area of the hypothalamus?
Paraventricular and supraoptic nucleus. Regulate water balance, secrete oxytocin and vasopressin. Anterior nucleus - stimulation causes heat dissipation. SCN - circadian rhythm.
181
How are sweet, bitter, and imani tastes received?
They bind to a GPCR. Sweet - closes K+ channels, bitter causes Ca++ release from the ER. Both result in neurotransmitter release.
182
What is sleep-related hypoventilation?
Increased PaCO2, particularly when sleeping. - reduction i ventilatory response to hypoxia. Headaches in morning, associated with decreased muscle muscle tone in REM.
183
What is primary and secondary damage?
Primary is damage from the initial trauma, secondary is indirect result of injury such as edema that comes from it.
184
What is the ventromedial nucleus of the hypothalamus?
Anterior (larger in females, sexually dimorphic) and Posterior (Satiety center - leptin binds).
185
Describe the organ or Corti.
Highly specialized cells on basilar membrane, 1 row of inner and 3 rows of outer hair cells (have stereocilia). Covered by tentorial membrane.
186
Describe CN III palsy.
Down and out, hypotrophic, abducted, intorted, ptosis, dilated pupil.
187
What type of receptor is GABAA, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Ionotropic. GABA. Increases Cl- conductance. Inhibitory.
188
Describe the basal ganglia direct pathway.
Cortex excites striatum, inhibits GPi, inhibits thalamus, excites cortex. Net excitation to cortex.
189
What is holoprosencephaly? What gene is it associated with?
Failure of the hemispheres to separate - varying severity. Associated with a SHH mutation.
190
What is anencephaly/craniorachischisis associated with?
B9 and maternal type I diabetes.
191
What are the components of the epithalamus?
Pineal gand (attached to 3rd ventricle by pineal stalk), and habernular nuclei (afferent from stria medullaris thalami, efferent to interpeduncular nuclei).
192
How many neurons are in sensory and motor pathways?
3 and 2.
193
What is the Brodmann's number for the primary somatosensory cortex and where is it?
Postcentral gyrus, 3, 1, 2.
194
What are the first 2 layers of the LGN?
Magnocellular - deals with movement and contrast - parasol ganglion cells. Layer 1 from the contralateral eye, layer 2 from the ipsilateral eye.
195
Describe A beta fibers.
Medium, myelinated, transmit mechanoreceptor info from skin.
196
What is doublecortin? What do mutations in it result in?
An MT-associated protein needed for proper neuronal migration. X-linked mutation results in males with lissencephaly (LISX1) or pachygyria, in heterozygous females it causes subcortical laminar band heterotopia.
197
What is the healthy response in caloric testing?
Cold water in left ear is right beating nystagmus. Warm water in left ear is left beating nystagmus.
198
What does Rexed's Lamina VI do?
Receives afferent signals from muscle spindles and joints.
199
What are the major dural venous sinuses?
Superior sagittal, straight, transverse (L&R), signoid (L&R).
200
What is conduction deafness vs sensorineural deafness?
Conduction deafness is a middle ear problem, sensorineural deafness is an inner ear problem.
201
Describe the golgi tendon reflex.
Ib afferent neuron responds to stretch, signals a spinal cord inhibitory interneuron, whicn signals an alpha motor neuron.
202
What are the pia mater projections into the ventricles?
The choroid plexus - where CSF is made.
203
What does the PICA supply?
Much of the inferior cerebellum, some lateral medulla, choroid plexus of the 4th ventricle.
204
Where are the fasiculus cuneatus and gracilis seen?
Gracilis all throughout cord, cuneatus at T6 and above.
205
What are Purkinje cells excitatory/inhibitory on?
Inhibitory on DCN via GABA.
206
Increased membrane permeability to which ions causes EPSP/IPSPs?
Na+ (and sometimes Ca++) is EPSP. Cl- and K+ is IPSP.
207
What type of neurotransmission does Nicotine work on and how?
Cholinergic. Nn agonist.
208
What is spina bifida rachischisis?
Neural tissue that's exposed degenerates.
209
What type of neurotransmission do non-BZ hypnotics work on and how?
GABAergic. Allosteric activator. Work on a narrow range of receptor subtypes.
210
Describe the anterior cerebral artery (ACA).
Goes medially through longitudinal fissure, supplies medial aspect of the brain. Is connected by the anterior communicating artery. Occlusion causes restricted (LL) contralateral and motor and somatosensory deficits.
211
What is the Hoffman's reflex?
Caused by UMN damage, flexion and adduction of the thumb when the middle fingernail is flicked downward.
212
What are the five types of neurons in the cerebellar cortex?
Granule cells and Golgi cells in granule cell layer - granule cell axons extend up to molecular layer. Purkinje cells (axons head out into molecular layer into DCN). Basket cells and Stellate cells in molecular layer - basket cells reach down to Purkinje layer.
213
What type of neurotransmission does Fluoxetine work on and how?
Serotonergic. SSRI.
214
How can motor tracts be classified?
By their position within the spinal cord (medial or lateral), or from where they originate (brain or brainstem).
215
What surrounds the endolymph?
Reissner's/Vestibular membrane. 2 layers of simple squamous epithelium.
216
Where does the STN get info from and send info to?
Gets excitatory from cortex, gets inhibitory from GPe. Sends excitatory to GPe, GPi, SNr. Modulatory signals from SNc.
217
Describe the flow of CSF.
Choroid plexus to ventricles to subarachnoid space to villi to sinuses to IJV.
218
Is the withdrawal reflex monosynaptic or polysynaptic?
Polysynaptic.
219
How does Ethosuximide work?
Blocks inactivated T-type Ca++ channels.
220
What modalities does CN IV transmit and what nuclei are they associated with?
GSE (Trochlear nucleus).
221
What is the response in caloric testing for a coma with an intact brain stem?
Eyes move toward cold and away from warm - slowly and once.
222
Where is the Abducens nucleus?
Mid-pons.
223
What are the three layers of the cerebellar cortex?
Molecular (outermost), Purkinje cell, Granule cell.
224
What produces the endolymph?
Stria vascularis (vascularized pseudostratified epithelium).
225
How does the sleep of depressed people differ?
Long first REM period.
226
What modalities does CN IX transmit and what nuclei are they associated with?
All of them! BE (Nucleus ambiguus). GVE (Inferior salivatory nucleus). SVA&GVA (Nucleus solitarius). GSA (Main sensory and spinal nucleus of V).
227
What types of papillae have taste buds?
Fungiform, circumvallate, foliate.
228
What causes appendicular ataxia? How do they present?
Usually lesions to the cerebellar hemispheres/lateral zone. Present with dysdiadochokinesia, hypotonia, dysmetria, and cannot pass the finger-nose-finger test.
229
What type of neurotransmission does Ondansetron work on and how?
Serotonergic. 5HT3 antagonist.
230
How can the internal carotid affect vision?
Can compress the lateral optic chiasm and cause unilateral nasal hemianopia.
231
What type of receptor is M3, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Acetylcholine Increases IP3/DAG. Excitatory.
232
What type of receptor is Nn, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Acetylcholine/nicotine. Increases Na+/Ca++ conductance. Excitatory.
233
Describe the anterior spinocerebellar pathway.
DRG via fasciculus gracilis to spinal border cells (lumbar regions of laminae VI-VII). Fibers cross in AWC, ascend via anterior spinocerebellar tract (anterior lateral funiculus), cross again in brainstem, pass through superior cerebellar peduncle to cerebellum.
234
What sort of pain do NSAIDs block?
Nociceptive. Also inflammatory disease, fever.
235
What are the components of the limbic system?
Hypothalamus, thalamus, epithalamus. Subcortical, allocortex, justallocortex. Limbic midbrain. Other inputs.
236
What is in the preoptic area of the hypothalamus?
Medial Preoptic Nucleus (sexually dimorphic, larger in males - center of male-typical sexual behaviour). Lateral Preoptic Nucleus (may generate REM and nonREM sleep). Median Preoptic Nucleus (thirst). Preoptic paraventricular nucleus (helps SCN in sleep).
237
What is important in short-term memory?
Prefrontal cortex.
238
What kind of neurons are in the locus coeruleus?
Norepinephrine.
239
What is decorticate rigidity?
UL flexed, LL extended. Supratentorial lesion, all brainstem nuclei intact.
240
What type of neurotransmission does Levodopa work on and how?
Dopaminergic. A substrate for dopamine synthesis.
241
What is Narcolepsy? How do you treat it?
Sleep attacks at least 3x per week over at least 3 months (spontaneous REM attack). Also has cataplexy, hypocretin/orexin deficiency, (less than 1/3 normal), rapid REM onset (1st 15 mins). Might also have sleep paralysis, hypnagogic hallucinations, excessive daytime sleeping. Treat with regular sleep schedule with many naps, Modafinil (D reuptake blocker, increases Glu, decreases GABA).
242
How does Cartamazepine work?
Blocks inactivated Na+ channels. Slows recovery from inactivation phase, inhibits repetitive neuronal firing/anticonvulsant.
243
How does a lesion rostral to the pyramidal decussation affect the corticospinal tract?
In the medulla - ipsilateral tongue paralysis, in the pons - ipsilateral facial muscle/lateral rectus paralysis, in the midbrain - most eye movements affected.
244
Which ganglia are involved in pupillary constriction and dilation?
Constriction - ciliary, dilation - superior cervical.
245
What is Marcus Gunn pupil?
Constricts consensually but not directly. Paradoxical dilation of both pupils.
246
Where are BMP and SHH expressed in neural development?
BMP dorsally, SHH ventrally.
247
What are the ossicles covered by?
Simple squamous epithelium.
248
What is the arcuate nucleus of the hypothalamus?
Some neurons release dopamine to inhibit prolactin. Some contain neuropeptide Y (NPY) and influence hunger. Ghrelin and leptin affect it.
249
Where is the nucleus ambiguus?
The medulla.
250
Where does the posterior spinocerebellar pathway get info from?
Proximal lower limb and trunk.
251
What type of neurotransmission does LSD work on and how?
Serotonergic. 5HT1A autoreceptor agonist.
252
Describe Pacinian corpuscles.
Deep, rapidly adapting. Detect surface texture.
253
Describe the cuneocerebellar pathway.
DRG via fasciculus cuneatus to lateral/exernal/accessory cuneate nucleus. Ascend via cuneocerebellar tract through inferior cerebellar peduncle to cerebellum.
254
What kind of neurons does ALS affect?
UMNs and LMNs.
255
Describe the meningeal spaces.
Epidural (real in spine, potential in brain), Subdural (always potential), Subarachnoid (always real, enlarged in cisterns).
256
What are the derivatives of the metencephalon?
Pons, cerebellum. Also upper fourth ventricle.
257
What are the functions of the hypothalamus?
Hemostasis, Endocrine, ANS, Limbic.
258
How long is the sleep cycle?
Initially about 90 mins but gets shorter through the night to about 40 mins.
259
What modalities does CN I transmit?
SVA (smell).
260
What is Restless Leg Syndrome?
Creeping/crawling sensation in leg at rest alleviated temporarily by movement. Must have 3x a week for at least 3 months. 2X higher in females, increase sin pregnancy. Treat with exercise and increased sleep time, Ropinorule (Dopamine agonist).
261
What are the visual system pathways?
Primary, pupillary light reflex, tectospinal, retinohypothalamic.
262
What is tonotopy?
Distribution of tone of sounds - higher pitched ones closer to the base, lower pitched ones travel to the helicotrema.
263
What determines if the neocortex is granular or agranular? What kind of cortices are which?
The layer IV development. Primary sensory areas tend to be granular, primary motor areas tend to be agranular.
264
What is middle medullary syndrome and what are its other names?
Inferior alternating syndrome, Dejerine's syndrome. Occlusion of an anterior spinal artery branch at the level of medulla, or medullary branches of the vertebral artery. Affects medial lemniscus (contralateral touch), corticospinal (contralateral motor), and hypoglossal nucleus (ipsilateral tongue).
265
What's the name of the space filled with endolymph?
Scala media.
266
Where does the vestibulospinal tract originate and decussate and terminate?
Lateral originates in lateral vestibular nucleus of medulla, doesn't cross. Medial originates in medial, lateral, and inferior vestibular nuclei, crosses partially in medulla. Both terminate in Laminae VII-IX, lateral at all levels but mainly lumbar, medial in cervical.
267
What makes up the lentiform nucleus?
Globus pallidus and Putamen.
268
Describe the pupillary light reflex.
Light comes in via CN II, goes to LGN (also goes to E-W nucleus), pretectal area -\> Edinger/Westphal nucleus. CN III goes to ciliary ganglion and constricts. \*LGN goes to both E-W nuclei from each pretectal area.
269
What is Gerstmann's syndrome?
Agraphia, acalculia, right-left disorientation, finger agnosia. Lesion localized strongly to dominant inferior parietal lobule in the angular gyrus.
270
What are the minor dural sinuses?
Inferior sagittal, occipital, superior petrosal (L&R), inferior petrosal (L&R).
271
What modalities does CN VIII transmit and what nuclei are they associated with?
SSA (Vestibular Nuclei and Cochlear Nuclei).
272
How is GABA made?
Decarboxylation of Glu.
273
What type of neurotransmission does Flumazenil work on and how?
GABAergic. BZ-site antagonist for overdose.
274
How are neural tube defects detected?
By ultrasound, also elevated alpha-fetoprotein levels.
275
What modalities does CN XI transmit and what nuclei are they associated with?
GSE (Accessory nucleus).
276
Where does the GPe get info from and send info to?
Gets excitatory info from STN and inhibitory info from striatum. Sends inhibitory to striatum, GPi, STN, SNr.
277
What happens when you lesion the LGN?
Contralateral homonymous hemianopia.
278
What is the main blood supply of the thalamus?
Deep branches of the posterior cerebral artery.
279
What is kinetosis?
Motion sickness, what you see =/= what you feel.
280
Describe taste receptor cells.
~100 in each taste bud, each one synapses with a primary taste neuron. Spindle-shaped, modified neuroepithelial cells. Innervated by afferent nerve fibers penetrating basal lamina.
281
What type of receptor is M1, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Acetylcholine. Increases IP3/DAG, decreases K+ conductance. Excitatory.
282
What are the maculae in the vestibular system?
Saccular (looks at vertical acceleration/deceleration) and Utricular (horizontal).
283
Where is the insula?
"5th lobe" under the sylvian fissure.
284
Where is the main input of the paleocerebellum and what deep cerebellar nucleus does it work with?
Main inputs from sensory/motor cortices, works with interposed (emboliform and globose).
285
Describe the flow of CSF within the ventricles.
Lateral ventricle to third via L/R interventricular foramina (foramen of Monro) then to fourth via cerebral aqueduct. Then to either cerebromedullary cistern via medial apertuer (foramen of Magendie) or to quadrigeminal cistern via L/R lateral apertures (foramen of Luschka).
286
What modality does the lateral corticospinal/pyramidal system transmit?
Voluntary motor.
287
What causes trigeminal neuralgia?
Thought to be due to demyelinationn due to pressure from a small aberrant artery. Triggered by moving mandible, smiling, yawning, tactile stimulation. Remove artery or give Carbamazepine.
288
Describe the dural venous sinuses.
Between the two layers of dura mater in the brain, receive CSF and drain into the IJV.
289
Where is the motor nucleus of V?
In the mid-pons.
290
Where does the reticulospinal tract originate and decussate and terminate?
Lateral originates in medulla and decussates partially there, medial originates in pons and doesn't cross. Both terminate at Laminae VII-IX at all levels of the spinal cord, the medial is primarily circular.
291
When does the neural tube close?
Cranially day 24/25, caudally day 26/27.
292
Who are the largest demographic of spinal cord injuries?
Caucasian males. Males 78%.
293
What are the nociceptive specific Rexed's Laminae.
I (Posteromerginal nucleus), II (substantia gelatinosa).
294
What type of neurotransmission does Ketamine work on and how?
Glutamatergic. NMDA antagonist.
295
What does the stapes push on?
The oval window. Vibration causes movement in cochlear fluid.
296
What is neuronal plasticity?
The ability of neurons to reorganize themselves and their connections.
297
Where is there adult neurogenesis?
Very limited, in hippocampus and olfactory bulb. It's derived from glia not stem cells.
298
What are association fibers? What are the different types?
Primarily I-III layers, connect different cortical areas in one hemisphere. Arcuate fibers, superior longitudinal fasciculus, arcuate fasciculus, uncinate fasciculus.
299
What is the P-pathway?
The parvocellular layers will terminate in layer 4Cbeta.
300
What can cause vertigo?
Peripheral lesions affecting vestibular inner ear labyrinth or vestibular CN III division.
301
What type of receptor is 5HT1, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Responds to serotonin. Inreases K+ conductance, decreases cAMP. Inhibitory.
302
Are cerebellar functions ipsilateral or contralateral?
Ipsilateral.
303
When do night terrors and somnambulism occur?
N3.
304
What are the denticulate ligaments?
Spinal pia mater projections through the arachnoid to the dura.
305
What are the types of stroke?
Ischemic or hemorrhagic.
306
What is the sensorimotor cortex loop?
Sensorimotor cortex to putamen to globus pallidus to VA or VL of thalamus.
307
What is the VTA?
Ventral tegmental area. Dopaminergic neurons. It and its associated nucleus accumbens is important in intense love and obsessive behaviour. Helps calculate gains and losses of situations.
308
What type of receptor are D2, D3, D4, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Responds to dopamine. Decrease presynaptic Ca++ conductance, postsynaptically K+ conductance increases, cAMP decreases. Inhibitory.
309
Where is the Trochlear nucleus?
In the lower midbrain.
310
Where is language and math ability lateralized to?
The left hemisphere in 95% of righties, 70% in lefties.
311
What modalities does CN VII transmit and what nuclei are they associated with?
All of them! BE (Facial nucleus). GVE (Superior salivatory nucleus). SVA&GVA (Nucleus solitarius). GSA (Main sensory and spinal nucleus of V).
312
What is Tabes dorsalis?
Tertiary neurosyphillis that destroys the dorsal column , particularly in the lower spine.
313
Where does the rubrospinal tract originate and decussate and terminate? Also, what does it do?
Originates in red nucleus (caudal magnocellular part), decussates in midbrain, terminates in Laminae VI-VII of the primarily cervical spinal cord. It facilitates motor neurons that innervate flexors, especially upper limb flexors.
314
What does layer VI of the neocortex do?
Outputs to the thalamus.
315
What makes up the striatum?
Caudate nucleus, Nucleus accumbens, Putamen.
316
What does the central sulcus separate?
The frontal and parietal lobe.
317
Describe conduction aphasia.
Fluent but repeated attempt at the correct word, errors increase with length and complexity of phrase.
318
Describe the lateral spinothalamic pathway.
First neuron enters dorsal root ganglion and synapses. Can first ascend/descend 1-2 levels via Lissauer's tract. Second neuron crosses over in anterior white commissure then goes up to the VPL in the thalamus. The third neuron goes to the somatosensory cortex.
319
Describe a subdural hematoma.
Crescens, expansion stops at dural reflections. Dural venous sinus or vein at attachment to sinus.
320
Where is the inferior salivatory nucleus?
Upper medulla.
321
How does a lesion to the pyramidal decussation affect the corticospinal tract?
Rostral portion results in the bilateral paresis of upper limbs, caudal portion results in the bilateral paresis of lower limbs.
322
What kind of drug is duloxetine, how does it work and what kind of pain does it treat?
An SNRI antidepressant (2nd gen). Blocks monoamine uptake (serotonin, NorE, some dopamine). More selectivity than antitryptilline. Treats neuropathic pain.
323
What modalities does CN XII transmit and what nuclei are they associated with?
GSE (Hypoglossal nucleus).
324
What are the types of afferent fibers to the cerebellum?
Mossy fibers (terminate as excitatory synapses on granule cell dendrites, provide info about movements). Climbing fibers (axons from inferior olivary nucleus, 'climb' Purkinje fibers, terminate as excitatory synapses, provide ino about errors in execution of movement). Both also terminate on the DCN, which balances (+) and (-) signals to decide what to do.
325
Where is the cutoff for hydrocephalus to become communicating / non-obstructive.
Out beyond the subarachnoid space (in the villi or granulations).
326
How are neurotransmitters created from the decarboxylation of amino acids?
AA decarboxylase. Tyr into Dopa, E, or NorE. Trp into 5'OH Trp into serotonin, melatonin. His into histamine.
327
Where are the 2nd and 3rd order neurons in the gustatory system?
2nd - ascend in the solitariothalamic tract to synapse in VPM. 3rd - projects to primary gistatory area.
328
What type of neurotransmission do Amphetamines work on and how?
Dopaminergic. Increase dopamine release.
329
Where is the nucleus solitarius?
Lower pons through to almost the entire medulla.
330
Which is the meninges are pain sensitive?
Dura mater.
331
What are the impairment scores of spinal cord injuries?
A (complete loss below the level of injury). B (some sensory preserved). C (less than half of muscles cannot move against gravity), D (more than half of muscles can move against gravity). E (normal).
332
What are the types of encephalocele?
Meningocele, meningoencephalocele, meningohydroencephalocele.
333
Describe Wernicke's area.
Speech comprehension. Brodmann number 39,40,22.
334
Is drug dependence necessary for addiction?
No.
335
What are the types of associative cortical regions?
Unimodal (get input from a single primary cortex) and heteromodal (get input from several primary cortices).
336
What is One-and-a-half syndrome?
MLF and abducens (and maybe PPRF) all on same size affected. Neither eye adducts, ipsilateral eye also can't abduct.
337
What is the gate control theory of pain?
Rubbing makes the A beta fibers excite inhibitory neurons and that's louder and drowns out the pain.
338
Where is the Oculomotor nucleus?
In the upper midbrain.
339
What is the Weber's test?
Checks lateralization. Conduction loss is louder in the affected ear, sensorineural loss is louder in the unaffected ear.
340
What are the layers of the olfactory bulb?
Olfactory nerve layer, glomerular layer, external and inner plexiform layers (mitral, tufted, granule cell).
341
What is sacral sparing?
If the most lateral perimeter of the cord is spared by a lesion, the sacral dermatomes (genitals, anal region) remain intact.
342
Describe the maculae.
Thickened epithelium, hair cells, stereocilia (kinocilia) embedded in the otolithic membrane (calcium crystals).
343
What is the difference between an autoreceptor and a heteroreceptor?
Autoreceptors regulate the turnover of the same neurotransmitter that activates them. Heteroreceptors are activated by a different neurotransmitter than the one they regulate the turnover of.
344
What is somatotopy?
The orderly representation of body parts within a cortex.
345
What are the three states of consciousness?
Sleeping, dreaming, awakenness.
346
Where is the main sensory nuleus of V?
In the mid-pons.
347
What effect will an occlusion of the paramedial branches of the basilar arteries have?
Affects corticospinal tract, facial muscles, abducens nucleus, pontine gaze center.
348
What function is generally lateralized to the non-dominant hemisphere?
Attention.
349
What occlusions cause Broca's and Wernicke's aphasia?
Broca's superior MCA, Wernicke's inferior MCA.
350
What is the response for caloric testing for a lower brain / brain stem lesion?
Nothing.
351
Describe the ophthalmic artery.
Travels along CN II to supply eyeball and other things.
352
What nerve roots and nerves do the biceps brachii, brachioradialis, and triceps reflex text?
C5/musculotaneous n., C6/radial n., C7/radial n.
353
What is nystagmus?
Slow phase of movement followed by fast phase in opposite direction.
354
What type of neurotransmission does Felbamate work on and how?
Glutamatergic. NMDA antagonist.
355
Where does the striatum get info from and send info to?
Gets excitatory info from cortex and thalamus. Sends inhibitory signals to GPe, GPi, SNc, SNr. Also gets some dopaminergic feedback from SNc.
356
What type of neurotransmission do Benzodiazepines work on and how?
GABAergic. Allosteric activator. Work on a broad range of receptor subtypes.
357
Which nerves have PNS fibers?
III, VII, IX, X.
358
How many things can you hold in short-term memory without repetition?
7 +/- 2.
359
What is Insomnia? How do you treat it?
Can be primary or secondary (issue of another disorder). Associated with drug/alcohol abuse. Inability to sleep. Tend to have 30% lower GABA. Treat with behavioural therapy, Ramelteon (melatonin receptor agonist).
360
What are the zones of the cerebellum and what do they do?
Lateral/Pontocerebellar/Neocerebellar (coordinates planning of movements). Intermediate/Paleocerebellar/Soinocerebellar (adjusts ongoing lateral motor movements/regulates muscle tone). Vestibulocerebellum/Archicerebellum (controls balance and eye movements).
361
What effect will an occlusion of the short circumferential branches of the basilar arteries have?
Will affect descending sympathetic fibers, spinothalamic, and pontocerebellar fibers.
362
Describe A delta and C fibers.
Muelinated. Pain, sensitive, itch. Lamina II gets from C fibers. Lamina V from A beta, A delta, C.
363
What kind of light stimulates awakenness?
Blue light (460-500nm).
364
What are Watershed zones?
Areas supplied by the branches of 2 major arteries.
365
Where does the corticobulbar tract originate and travel and terminate?
In the primary motor cortex, frontal eye fields (FEF), and primary somatosensory cortex. Travels in the genu (motor cortex), caudal portion of anterior limb (FEF), rostral portion of posterior limb (somatosensory cortex). Terminates in CN nuclei.
366
Describe the anterior corticospinal system.
UMNs in primary motor cortex, axons travel via internal capsule through cerevral peduncle, pons, and pyramidalis. Synapses in ventral horn (some decussate first, so there's bilateral innervation), outputs to voluntary skeletal muscles. Pathway ends in the mid-thoracic region.
367
Describe olfactory coding.
Some neurons responsive to a single odorant, some to multiple, different combinations let us respond. Perception of odour can change with concentrations.
368
What type of receptor is M2, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Acetylcholine. Increases K+ conductance. Inhibitory.
369
What type of receptor is the D1-like family (D1, Ds). what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Responds to dopamine. Increases cAMP. Inhibitory.
370
What are the fibers in the posterior limb of the internal capsule?
Mainly corticospinal, some medial lemniscus and spinothalamic fibers, a few corticobulbar fibers.
371
What type of neurotransmission do Barbituates work on and how?
GABAergic. Allosteric activator.
372
What type of neurotransmission does Phenelzin work on and how?
Adrenergic, inhibition of monoamine oxidase.
373
What are the lateral motor pathways?
Corticospinal, rubrospinal.
374
In how many cases of Shingles (herpes Zoster) does it resurface in V1?
10-25%
375
What type of receptors are NMDA/AMPA, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Respond to glutamate. Increase Na+ and Ca++ conductance. Excitatory.
376
What are the nuclei in the tuberal area of the hypothalamus?
Dorsomedial, ventromedial, arcuate.
377
What does the corticospinal tract transmit?
Voluntary motor below the neck.
378
List the subarachnoid cisterns.
Interpeducular (optic chiasm), Pontine, Quadrigeminal, Cerebromedullary (aka cisterna magna).
379
Describe REM slep.
Beta waves on EEG. Muscular atonia, dreaming. 20-25% of sleep.
380
What are the types of sensory axons?
Ia (muscle spindles) and Ib (golgi tendon organs).
381
Describe the DCML pathway.
First neuron comes in through the DRG, then moves up via fasciculus cuneatus/gracilis to synapse in nucleus cuneatus/gracilis in the caudal medulla. The second neuron crosses over and ascends via the medial lemniscus to the VPL in the thalamus. The third neuron goes to the primary somatosensory cortex.
382
What are the ventromedial motor pathways?
Tectospinal, medial/lateral vestibulospinal, medial/lateral reticulospinal.
383
What type of neurotransmission does Phencyclidine work on and how?
Glutamatergic. NMDA antagonist.
384
What type of receptor is 5HT4, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Responds to serotonin. Decreases K+ conductance. Excitatory.
385
Where is the primary gustatory cortex? And what is its Brodmann number?
Most lateral part of postcentral gyrus, lateral sulcus folds over operculum. 43.
386
What is Horner's syndrome?
Ptosis, miosis, anhydrosis.
387
How does referred pain work?
Visceral structure signals pass through Lamina V too.
388
What does the posterior commissure connect?
Prerectal nuclei for the pupillary light reflex.
389
What is the dorsomedial nucleus of the hypothalamus?
Stimulation results in hyperphagia (obesity) and rage. Some neurons make orexin.
390
Describe Rexed's Lamina VII?
Nucleus dorsalis and Clarke's nucleus - non noxious receptors for the manipulatoion of joints. Interomediolateral nuclei respond to noxious and more complex stimuli (sympathetic and proprioception). Only found T1-L2.
391
What are 'right-way' eyes?
Eyes facing away from the motor deficit.
392
What are the branches of the internal carotid?
Opthalmic, Anterior choroidal, Posterior communicating, Middle cerebral (MCA), Anterior cerebral (ACA).
393
What is the association cortex loop?
Association cortex to Caudate to SCN & globus pallidus to Disromedial nucleus of the Thalamus.
394
Describe A alpha fibers.
Large, myelinated, transmit proprioceptive info.
395
What is the sylvian fissure?
AKA the lateral sulcus, separates the temporal lobe from the frontal and parietal lobes.
396
How do neurons migrate?
They start in the ventricular zone, ride radial glia up into cortical plate or stopping in marginal zone at pial border. Younger neurons push up through the older ones.
397
Where is the hypoglossal nucleus?
Medulla.
398
What does the LGN process?
Vision from the contralateral visual field.
399
How does reciprocal inhibition in the deep tendon reflex work?
Ia afferent neuron bifurcates - one branch goes to the alpha motor neuron making the limb flex, the other to a Ia inhibitory interneuron that goes to the opposing muscle.
400
Where do the GPi and SNr get info from and send info to?
Get excitatory from STN, get inhibitory from striatum and GPe. Send inhibitory info to thalamus.
401
Describe the anterior inferior cerebellar artery (AICA).
Supplies anterior inferior cerebellum and part of pons. Has a labyrinthine branch that supplies the inner ear. Occlusion results in Lateral Pontine Syndrome - Affects spinothalamic, descending tract of V, inferior cerebellar peduncle and vestibular nuclei, descending sympathetic fibers (Horner's syndrome), cochlear nuclei, facial nucleus, main sensory and motor nucleus of V.
402
What is the olfactory binding protein?
A protein on the cilia of the primary olfactory receptors, made by the Bowman's glands in the olfactory mucosa, that binds to and concentrates the odorant around the cilia.
403
When do neural areas mature (pruning)?
Primary and unimodal cortical areas mature first at around puberty, prefrontal/parietal multimodal areas end at ~20 years.
404
Describe the olfactory epithelium.
Bipolar neurons with the dendrites terminating in the mucosa as the expanded olfactory knob. Single unmyelinated axons pierce the cribiform plate.
405
Describe the anterior choroidal artery.
Supplies choroid plexus in the lateral ventricle, also optic tract, some of cerebral peduncle, other structures as it passes.
406
Describe the mesolimbic dopaminergic pathway.
In the medial forebrain, it's a pathway where dopaminergic neurons from the ventaral tegmental area synapse with the nucleus accumbens (in front of the hypothalamus).
407
What are the four phases of spinal shock\>
1 (0-1d): areflexia/hyporeflexia, loss of descanding facilitation. 2 (1-3d): initial reflex return, denervation supersensitivity. 3 (1-4w): hyperreflexia, axon-supported synapse growth. 4 (1-12m): hyperreflexia, spasticity, soma-supported synapse growth.
408
What are the components of the pineal gland?
Round pinealocytes (secretory - melatonin and some serotonin), interstitial cells (modified astrocytes), corpora aranaeum (EC mineral deposits).
409
What modalities does CN VI transmit and what nuclei are they associated with?
GSE (Abducens nucleus).
410
Describe sleep apnea.
Interruption of breathing in sleep, mostly men 40-80, often obese. Can be obstructive or central. Treat with weight loss, behaviour conditioning, airway device.
411
What type of receptor is Kainate, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Ionotropic. Responds to glutamate. Increases Na+ conductance. Excitatory.
412
Where is the primary olfactory cortex?
In the uncus in the ventral surface of the temporal love.
413
What are the types of long term memory?
Declarative (episodic or semantic) - virtually unlimited storage capacity. Procedural "how-to". Includes basal ganglia, premotor cortex, cerebellar. Problems seen in Huntington's and Parkinson's.
414
What do you get if you knock out some of both hemispheres?
Severe right neglect.
415
What are the fibers in the anterior limb of the internal capsule.
Frontopontine/corticofugal and thalamocortical fibers.
416
What is the cause of Athetosis? Describe it.
Degeneration of the striatum. Hyperkinetic, irregular, slow movement especially in the fingers.
417
What are the branches of the basilar artery from rostral to caudal?
Anferior inferior cerebellar (AICA), Superior cerebellar, Posterior cerebral, also minor Paramedial branches, long circumferential branches and short circumferential branches.
418
What is an acoustic neuroma?
AKA a vestibular schwannoma, tumour in myelin sheath surrounding CN VIII.
419
How does a lesion in the internal capsule affect the corticospinal tract?
Contralateral deficit in movement.
420
What are granule cells excitatory/inhibitory on?
Excitatory on all cells.
421
Describe the subarachnoid cisterns?
Openings in the space made by the separation of arachnoid and pia mater (also filled with CSF).
422
What modalities does CN III transmit and what nuclei are they associated with?
GSE (Oculomotor nucleus). GVE (Edinger-Westphal nucleus). Goes to ciliary ganglion.
423
What is LIS1?
A gene coding for an MT-associated protein important for proper neuronal migration speed. An autosomal dominant mutation results in Miller-Dicker syndrome, causing type 1 lissencephaly.
424
What is the role of the SNc?
Functions on striatum, inhibits indirect pathway and excites direct pathway - stimulates movement.
425
What are dystonia and dysmetria?
Disordered tonicity of muscle and improper measuring of distance in muscular acts.
426
How does acetaminophen work and what kind of pain does it treat?
Not poorly understood but has central effects - crosses BBB. Analgesic and antipyretic. Treats mild-moderate nociceptive pain and fever (moderate-severe when combined with opioids).
427
What type of receptor are Group II and III, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Respond to glutamate. Decrease cAMP. Inhibitory.
428
What does the corticobulbar tract transmit?
Voluntary motor to the head and neck.
429
What type of neurotransmission does Clonidine work on and how?
Adrenergic. Alpha2 agonist.
430
What are the cortices besides the neocortex and how many layers do they have?
Allocortex (archicortex (hippocampus) and paleocortex (olfactory), 3 layers) Juxtallo/periallocortex (4-5 layers, entorhinal, parahippocampal, cingulate, orbitofrontal) Subcortical (amygdala, basal forebrain).
431
What is filamin? What do mutations in it result in?
An actin-binding protein that is important for the initiation of neuronal migration. X-linked dominant FLNA mutation results in periventricular heterotopia. Seen in females, main symptom is late-onset epilepsy.
432
Where is the dorsal motor nucleus of X?
Medulla.
433
What are the types of hemineglect?
Sensory, motor-intentional, conceptual. Or combinations.
434
What type of receptor is the alpha2 receptor, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic. Responds to adrenaline. Decrease of presynaptic Ca++ conductance, postsynaptic decrease of cAMP and inrease of K+ conductance. Inhibitory.
435
What is the cause of Huntington's? Describe it.
Degeneration in Caudate, striatum, medium spiny neurons. A CAG repeat on C4. Onset of symptoms between 20 and 50 years old. Chorea, athetosis, aggression, depression dementia.
436
What muscle, nerve root, and nerve does the patellar/knee jerk reflex test.
Quadriceps femoris, L4, femoral n.
437
What effect will an occlusion of the long circumferential branches of the basilar arteries have?
Will affect spinothalamic gaze centers.
438
What modalities does CN V transmit and what nuclei are they associated with?
BE (Motor nucleus of V). GSA (Main sensory nucleus of V for touch, spinal nucleus of V for pain, mesencephalic nucleus for proprioception).
439
What type of receptor is Group I, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Metabotropic Responds to glutamate. Increases IP3/DAG. Excitatory.
440
What sensation does the spinothalamic pathway transmit?
Pain and temperature in the lateral tract. The anterior tract also carries some light (crude) touch.
441
What is the withdrawal reflex often accompanied by?
The crossed-extensor reflex. Sensory neuron signals the CNS which signals many interneurons, which go either to the alpha motor neuron to flex the hurt leg or to more interneurons that extend the other leg.
442
How much of the human cerebral cortex does the neocortex comprise?
95%
443
A lesion to the motor cortex / FEF causes which way eyes?
Right way eyes.
444
What is the Brodmann's number for the primary auditory cortex and where is it?
Under sylvian fissure, 41,42.
445
What type of neurotransmission does Methylphenidate work on and how?
Adrenergic, inhibition of NorE reuptake.
446
Why does hydrocephaly sometimes develop in spina bifida?
The cord is tethered to the column, brainstem may be pulled and therefore the CSF flow cut off.
447
What are the types of motor axons?
Alpha (innervates extrafusal muscle fibers) and gamma (innervates intrafusal muscle fibers).
448
What do you get if you knock out the right hemisphere (in most people)?
Severe left neglect.
449
How is the middle ear connected by the nasopharynx?
Eustacian tube. Can cause otitis media.
450
Describe the middle cerebral artery (MCA).
Travels in the lateral sulcus. Supplies insula and most of the lateral aspect of the brain. Has some lenticulostriate branches which come off and supply the deeper structures like the internal capsule and the basal ganglia. Occlusion causes restricted (face+UL) contralateral and somatosensory deficits.
451
What are the secondary vesicles of brain embryological development and when do they develop?
5th week. Telencephalon and Diencephalon (from Prosencephalon), Mesencephalon, Metencephalon and Myencephalon (from Rhombencephalon).
452
Where in the brain are face pain and touch tracts mixed and where are they separate?
Above pons mixed, below pons just pain.
453
What is the axon reflex?
No intergration center or synapses, not a 'true' reflex. Signalling starts in the middle of the sensory axon at the stimulation site and transmits signals antidromically directly to the effector.
454
What type of neurotransmission does Metyrosin work on and how?
Adrenergic, inhibition of tyrosine hydroxylase.
455
Where does the corticospinal tract originate, travel, and decussate?
Originates in the primary motor cortex, primary sensory cortex, premotor and supplemental motor areas (40% from 3,1,2, 30% each from 4 and 6). Travels in posterior limb of the internal capsule. 90% decussates in medullary pyramids, other 10% decussate at spinal cord.
456
Which nerves receive GSA fibers from the epithelium?
Ant 2/3 of tongue - V Post 1/3 of tongue - IX Epiglottis - X
457
Do adult cochlear cells have kinocilium?
No
458
Where is there an intermediate zone between the dorsal and ventral horn?
T1-L2.
459
What sort of effects do aspirin and ibuprofen have?
Ibuprofen - analgesic, antipyretic, antiinflammatory. Aspirin - low doses antiplatelet and antipyretic, high doses analgesic and antiinflammatory.
460
What type of neurotransmission does Danezepil work on and how?
Cholinergic. Cholinesterase inhibitor.
461
Describe the lateral corticospinal/pyramidal system.
UMNs in primary motor cortex, axons travel via internal capsule through cerevral peduncle, pons, and pyramidalis. 85% of fibers cross in pyramidal decussation in the caudal medulla. Synapses in Ventral horn, putputs to voluntary skeletal muscles.muscles.
462
What are the trigeminal nerve reflexes?
Corneal, sicking, sneeze, jaw-jerk.
463
How does lidocaine work and what kind of pain does it treat? Also, how is it administered?
Blocks VG Na+ channels. Can treat nociceptive and neuropathic pain and can also treat V-tach. Cream or injection.
464
How much CSF is normally made?
400-500mL produces and reabsorbed daily. In an adult there is normally 150mL of CSF.
465
What are dysosmia and phantosmia?
Dysosmia is distorted odour perception, phantosmia is perception of odour where there isn't one.
466
What are the derivatives of the myencephalon?
Medulla and lower fourth ventricle.
467
What are the derivatives of the mesencephalon?
Midbrain and cerebral aqueduct.
468
Which is faster, the effect of ionotropic receptors or metabotropic receptors?
Ionotropic.
469
What do the dorsal and ventral horns of the spinal column do in general?
Dorsal - receives sensory input, Ventral - outputs motor.
470
How does coffee work to make you awake?
Blocks adenosine receptors - adenosine buildup associated with a need to make up sleep.
471
What are the arachnoid trabeculae and villi?
Trabeculae extend to pia (helps keep brain suspended), and villi pass out into the dural venous sinuses.
472
What do the optic radiations divide into?
The Parietal stream (carries from superior VF/inferior retinal quadrant) terminates in the cuneus. The Meyer's Loop/Temporal stream (carries from inferior VF/superior retinal quadrant) terminates in the lungual gyrus.
473
Describe Broca's area.
Pars opercularis + pars triangularis. Brodmann number 44/45.
474
What type of receptor is the alpha1 receptor, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Adrenergic. Metabotropic, Increase of IP3/DAG, decrease in K+ conductance. Excitatory.
475
What kind of chemical stimuli do olfaction and gustation detect?
Airborne and water-soluble respectively.
476
What is drug addiction?
Compulsive use of a substance despite harmful consequences.
477
What do the parts of the corpus callosum connect?
Genu - frontal lobes Body - posterior frontal lobes, parietal lobes, superior temporal lobes Splenium - occipital lobes
478
What nerves are involved in the corneal 'blink' reflex?
Afferent is CN V, efferent is CN VI.
479
What type of neurotransmission does Cocaine work on and how?
Dopaminergic. Inhibits dopamine reuptake.
480
What does vascular damage to one occipital lobe by way of the posterior cerebral a. do?
Hemi or quad anopia but with macular sparing.
481
Describe the posterior communicating artery.
Joins the posterior cerebral artery to the internal carotid.
482
What are the dura septa?
Falx cerebri, falx cerebelli, tentorium cerebelli, tentorial notch.
483
Where is the spinal nucleus of V?
Starts in the mid-pons, extends down to the medulla and the spinal cord.
484
How is a direction change processed in the vestibular system?
Endolymph shifts, direction shifts toward kinocilia increases signalling by SSA efferent axon. When rotation is stopped, axons fire again but with opposite patterns of excitation and inhibition. Long lasting rotation can cause adaptation.
485
Describe N2 of non-REM sleep.
K-complexes/sleep spindles on EEG. Light sleep. Decreased muscle activity, no conscious awareness of external environment, can grind teeth. 40-55% of sleep.
486
What type of receptor is 5HT3, what does it respond to, and by what mechanism does it work and is it excitatory of inhibitory?
Ionotropic. Responds to serotonin. Increases Na+ and Ca++ conductance. Excitatory.
487
Where do signals go from the emboliform and globose nucleus?
Through the SCP, across the midline, goes to the red nucleus.
488
Which nerves have BE modality?
V3, VII, IX, X.
489
What do Rexed's Laminae VIII, IX, X do?
Voluntary motor.
490
What is a golgi tendon organ?
A proprioceptive sensory organ made up of collagen fibers in a CT capsule, with sensory Ib axons winding arounf the collagen.
