Neuro Mod 5 Flashcards
Location of L and R thalami?
Lateral regions of diencephalon
“sit on top of the brainstem”
What is the diencephalon?
Inner portion of the brain surrounded by hemispheres
What structures make up the diencephalon?
Thalamus, hypothalamus, subthalamus, epithalamus (pineal body)
How to locate thalamus from transverse view?
Locate internal capsule –> thalamus & caudate are medial to IC
The thalamus is _____ to the caudate nucleus in transverse view
posterior
How to locate thalamus in frontal view?
Locate internal capsule –> thalamus & caudate nucleus are medial to IC
The thalamus is _____ to the caudate nucleus in frontal view
inferior
Blood supply to the thalamus?
Deep branches of the posterior cerebral artery (PAC) & posterior communicating arteries
Function of the thalamus?
Relays and regulates all sensory info except olfaction (CN1) and sends it to the cortex
All sensory info must reach the _____ before the brain can consciously detect, distinguish, and interpret sensory info (become aware)
Cortex
The thalamus acts as the gateway to what?
Consciousness
Visual pathway in the thalamus?
Eye -> thalamus -> primary visual cortex (area 17) -> secondary/associative visual cortices
Auditory pathway in the thalamus?
Ear -> thalamus -> primary auditory cortex (area 41) -> secondary/associative auditory cortices
Somatosensory pathway in the thalamus?
Body -> thalamus -> primary somatosensory cortex (area 3, 1, 2) -> secondary/associative somatosensory cortices
Basal ganglia (in thalamus) relays what info to the cortex?
Motor information (initiation and execution of movement)
Cerebellum (in thalamus) relays what info to the cortex?
Motor information (coordination of movement)
Limbic system (in thalamus) relays what info to the cortex?
Info related to fear, memory, learning, and other human behaviors/needs
Reticular connections (in thalamus) relays what info to the cortex?
Info that modifies and regulates consciousness, sleep/wake cycles, alertness, pain, etc.
The thalamus has _______ _______ that are responsible for relaying info to different regions of the cortex
Specific nuclei
Damage to one part of the thalamus can result in what?
Dysregulation of the sensory info that passes through that part of the thalamus
Where is the MGN (medial geniculate nucleus/body) located in the thalamus?
Medial bump in posterior thalamus
Where is the LGN (lateral geniculate nucleus/body) located in the thalamus?
Lateral bump in posterior thalamus
Where is the VPL (ventral posterior lateral) nucleus located in the thalamus?
Along lateral thalamus
Where is the VPM (ventral posterior medial) nucleus located in the thalamus?
Along medial thalamus
Where is the VL (ventral lateral) nucleus located in the thalamus?
Along lateral thalamus
Where does the MGN (medial geniculate nucleus/body) in the thalamus project info?
Primary auditory cortex (41)
Where does the LGN (lateral geniculate nucleus/body) in the thalamus project info?
Primary visual cortex (17)
Where does the VPL (ventral posterior lateral nucleus/body) in the thalamus project info?
Primary somatosensory cortex (3, 1, 2)
Where does the VPM (ventral posterior medial nucleus/body) in the thalamus project info?
Primary somatosensory cortex (3, 1, 2)
Where does the VL (ventral lateral nucleus/body) in the thalamus project info?
Primary and premotor cortex (4,6)
The MGN nucleus relays ______ info from _____ to ________
relays auditory info from brainstem to auditory cortex
The LGN nucleus relays ______ info from _____ to ________
relays visual info from eye (retina) to visual cortex
The VPL nucleus relays ______ info from _____ to ________
relays somatosensory info from spinal cord (body) to somatosensory cortex
The VPM nucleus relays ______ info from _____ to ________
relays somatosensory info from cranial nerves (head) to somatosensory cortex
The VL nucleus relays ______ info from _____ to ________
relays motor info from basal ganglia & cerebellum to motor cortices
What produces nociceptive pain/peripheral pain?
Non-neural tissue damage/injury
Process of nociceptive pain/peripheral pain?
Originates from nociceptive stimulation of peripheral nerve endings in injured/damaged non-neural tissue (tendon, muscle, bone) and provokes inflammatory/immune response (releases NT and cytokines that stimulate R’s)
What produces neuropathic pain?
Disease/injury to NS
What is neuropathic pain?
Sensation of pain (nociception) originating from dysfunctional/damaged nociceptive pathways in CNS (spinal cord, brainstem, thalamus, etc) or peripheral nerves
When is neuropathic pain referred to as central pain?
If the dysfunction to nociceptive pathways is in the CNS
What syndrome is an example of central neuropathic pain?
Thalamic pain syndrome (Dejerine-Roussy syndrome)
When does Thalamic pain syndrome occur?
After infarction of VPL of the thalamus or any of the CNS somatosensory pathways (internal capsule, brainstem)
Thalamic pain syndrome is considered what kind of stroke?
Lacunar or small vessel stroke
Symptoms of Thalamic pain syndrome?
Contralateral neuropathic pain/loss of sensation
*pain (shooting, burning, squeezing, stabbing, lacerating, freezing, cutting, throbbing)
With Thalamic pain syndrome, pain is abnormally provoked by what?
Normal stimuli/light touch, normal movement, temperature changes, stress
Where are basal ganglia structures located?
Diencephalon and midbrain (mesencephalon)
Anterior association areas in the brain receive sensory input from _____ _____ areas
posterior association areas
Anterior association areas in the brain receive physiological/emotional input from ______ _____ areas/ _____ system
Other prefrontal areas/limbic system
Which part of the brain makes the decision to act/sends decision to the premotor cortex?
Anterior association area
Which part of the brain assembles a motor plan for action?
Premotor cortices
The motor plan from the premotor cortices is sent to the primary cortex for what? What needs to be done before it reaches the primary motor cortex?
To activate muscles needed for execution of movement
**Needs to be modified and streamlined before getting here
Which structures modify/streamline final motor plans before primary motor cortex can activate muscles for voluntary motor movement?
Basal ganglia, cerebellum, thalamus
Basal ganglia pathway?
Anterior assoc. area –> premotor/primary motor cortices –> basal ganglia –> thalamus –> premotor/primary motor cortices –> brainstem/spinal cord
Lesions in the basal ganglia and cerebellum _____ motor function
Impair
Are basal ganglia movement impairments the same as cerebellar motor impairments?
No, very different
What kind of motor impairments w/ basal ganglia lesions?
Initiation & execution impaired, too much or too little movement (hyper or hypokinetic)
What kind of motor impairments w/ cerebellar lesions?
Motor tone, balance/posture, coordination (synergy)
The basal ganglia is a cluster of different _______ scattered throughout the _________?
Nuclei, diencephalon/midbrain
Which nuclei make up the basal ganglia?
Caudate nucleus, Nucleus accumbens, Putamen, Globus pallidus (external/internal), Subthalamic nuclei, Substantia nigra
Where is the substantia nigra nucleus located?
Midbrain of brainstem
The globus pallidus is located _____ to the putamen
Deep
The nucleus accumbens is the junction between which two nuclei?
Caudate and putamen
Caudate nucleus (basal ganglia) features?
Horn shaped, wraps around other basal ganglia structures (amygdala located near one end)
Putamen (basal ganglia) features?
Oval shaped structure that caudate wraps around, lateral to most other basal ganglia nuclei
Nucleus accumbens (basal ganglia) features?
Located at junction of caudate/putamen, difficult to identify and individual structure, **Role in pleasure/reward processing
Globus pallidus (basal ganglia) features?
External & internal, medial to putamen, triangular shape in frontal view
Subthalamic nuclei (basal ganglia) features?
Inferior to thalamus
Substantia nigra (basal ganglia) features?
Located in midbrain of brainstem
What basal ganglia structures can be seen in a vertical slice of the brain?
Top to bottom: Caudate -> Putamen -> Globus pallidus -> Subthalamic -> Substantia nigra
What basal ganglia structures can be seen in a horizontal slice of the brain?
Front to back: Caudate -> Putamen -> Globus pallidus (external -> internal) -> thalamus
In transverse and frontal views, the caudate nucleus is ____ to the internal capsule
Medial
In transverse and frontal views, the thalamus is ____ to the ____ internal capsule
Medial to posterior internal capsule
In transverse and frontal views, putamen/globus pallidus are located _____ to the IC and _____ to putamen in the “triangle” on frontal view
Lateral, medial
What two structures are referred to as the striatum?
Caudate and putamen
What two structures are referred to as the lenticular nucleus?
Globus pallidus and putamen
Majority of the basal ganglia structures are supplied by small penetrating branches of which artery?
MCA (middle cerebral artery)
*known as lenticulostriate arteries
A smaller potion of the basal ganglia is supplied by small penetrating branches of which artery?
ACA (anterior cerebral artery)
Function of the basal ganglia?
Initiate/execute movement
What are the 3 functional loops of the basal ganglia?
Motor (modifies motor plan), Association/cognitive (learning/choosing best way to initiate/execute), Limbic (emotional input that influences movement)
Motor loop pathway of basal ganglia?
premotor/motor cortex –> sends motor plan to putamen –> putamen sends plan to other nuclei to analyze/modify –> copy of plan is sent through direct (promotes movement) and indirect pathways (suppress movement) in basal ganglia –> globus pallidus internus packages final plan –> sends to thalamus –> relays final plan to motor cortex/appropriate muscles acitvated
Purpose of direct pathway supporting movement in basal ganglia motor pathway?
make sure final plan includes instructions to promote muscle movement needed to execute movement in best possible way
Purpose of indirect pathway suppressing movement in basal ganglia motor pathway?
make sure final plan includes instructions to suppress muscle movement NOT needed to execute specific movement in best possible way
Direct pathway of basal ganglia? Which NT affect this?
Putamen connects directly to globus pallidus internus (GPi) –> stimulates direct pathway
*dopamine & glutamate: stimulate direct pathway/movement
*Ach inhibits pathway/suppress movement
Indirect pathway of basal ganglia? Which NT affect this?
Putamen connects indirectly to globus pallidus internus (GPi):
Putamen –> GPe –> STN –> GPi
*dopamine: inhibits indirect pathway/promotes movement
*Ach and glutamate: stimulate indirect pathway/suppress movement
Role of substantia nigra in motor loop pathway/modifying movement?
Releases dopamine in putamen w/ net effect to promote movement
Role of putamen in motor loop pathway/modifying movement?
Cells release Ach w/ net effect to suppress movement
Basal ganglia motor loop pathway in healthy individual?
Balance of NT, appropriate signaling in putamen for initiation/execution in best possible way
Basal ganglia motor loop pathway in disease/pathology that decreases dopamine?
Hypokinetic disorder, allows Ach to dominate in putamen, suppresses movement
*difficulty initiating/executing movement
Basal ganglia motor loop pathway in disease/pathology that decreases Ach?
Hyperkinetic disorder, allows dopamine to dominate in putamen, promotes too much movement
*constant initiation/execution of abnormal movements
Movement disorders of the basal ganglia are characterized by what?
Movement speed
Most movement disorders of the basal ganglia cease during ____
Sleep
Bradykinesia/hypokinesia characteristics?
Slowed movement
Rigidity characteristics?
Inc. resistance, passive ROM, bi-directional, non-velocity or amplitude dependent
Lead pipe: resistance persists throughout ROM
Cogwheel: periodic resistance at different points throughout ROM
Rigidity vs. spasticity?
Rigidity not speed (velocity) dependent but spasticity is
Dystonia characteristics?
Involuntary (sustained or intermittent) muscle contraction that cause: twisting and repetitive movements, abnormal postures (or both)
*slower than athetosis
*can affect one muscle, group, or entire body (ex. cervical dystonia)
Athetosis characteristics?
Slow, continuous, involuntary writhing movement, prevents maintenance of stable posture
*Writhing twisting of limbs (hands/feet), trunk, or face
Chorea characteristics?
Ongoing, random appearing sequence of one or more involuntary movements/movement fragments
*continuous dance-like involuntary movement
*quality may vary (jerky to fluid)
Choreathetosis characteristics?
Athetosis movements combine w/ chorea type movement
Ballismus (hemi-ballismus) characteristics? Hemi-ballismus is associated w/ lesion of which nuclei?
Flailing, flinging, or rotary movements of proximal limbs
*hemi-ballismus assoc. w/ subthalamic nuclei lesion (STN, part of indirect pathway)
Tic characteristics? (motor vs vocal?)
Repeated, individually recognizable, intermittent movements
*fragments are briefly suppressable but usually assoc. w/ urge to perform movement
*motor: face/neck MC, less frequent w/ extremities
*vocal: sounds or words (commonly obscene)
Tremor characteristics? (resting vs intention?)
Rhythmic back and forth or oscillating involuntary movement about a joint axis
*resting: occurs at rest in postural position, once movement starts tremor diminishes
*intention: occurs as arm approaches object, stops when arm at rest in postural position
Myoclonus characteristics?
Sequence of repeated, often not rhythmic, brief shock-like jerks d/t sudden involuntary contraction/relaxation of one or group of muscles
*sudden, short circuit or shock like, vary in intensity/frequency
Clonus characteristics?
Muscular spasm involving repeated, often rhythmic, rapid contraction/relaxation
*often unidirectional
*quick stretch or deep tendon reflex may stimulate clonus in upper motor neuron (UMN) lesion
Common findings of hypokinetic movement disorders?
Bradykinesia, freezing, rigidity, postural instability
*Parkinson’s
Parkinson’s is a neurodegenerative disease that results in what?
Hypokinetic motor dysfunction: bradykinesia, difficulty initiating movement, freezing, increased muscle tone/rigidity, resting tremor, decreased voluntary movement (micrographia, dec. facial expression, monotone speech)
Non-motor symptoms of parkinsons?
Dementia/cognitive dysfunction, psychosis, hallucinations, mood disorders, sleep disturbances, fatigue, pain/sensory dysfunction, olfactory, GI, ANS dysfunction, derm findings (Seborrhea)
Pathophys of Parkinson’s?
Depigmentation, neuronal loss, proteinopathy, gliosis *particularly in substantia nigra pars compact
Proteinopathy of Parkinsons?
a-synuclein (aSyn) found in neurons, progressive accumulation causes neuron death/gliosis in substantia nigra/other regions of cortex
*form Lewy bodies
Lewy bodies from parkinsons in the substantia nigra respresent _____ of neurons and lead to ______ deficiency in the putamen
Death/atrophy, dopamine defiency
Lewy bodies from parkinsons found in the cortex can cause ______ symptoms
Non-motor
What is Lewy body dementia?
Accumulation of aSyn lewy bodies in cortex but spare the substantia nigra (dementia sx w/o hypokinetic motor sx)
Posture with Parkinson’s?
Stooped w/ head/neck forward, knees flexed, UE flexed w/ fingers extended
Gait with Parkinsons?
Rigidity, bradykinesia
difficulty initiating steps, decreased stride length (Marche a petit pas), festination (involuntary inclination to take accelerating steps), freezing
Common findings of hyperkinesia movement disorders of the basal ganglia?
Dystonia, athetosis, chorea, ballismus, myoclonus, tics, tremor
What it Huntington’s disease?
Inherited degenerative neurological dz causing: choreiform movement, dementia, behavioral changes
Prognosis of Huntingtons?
Progressive neurodegeneration leads to death w/in 10-30 yrs post sx onset
Proteinopathy of Huntingtons?
Huntington protein normally found in neurons throughout brain/body
*aggregates formed from mutated huntington protein accumulates w/in neuron (from abnormal huntington gene) and causes neuronal death in caudate & putamen (and other areas of CNS)
Pathophys of caudate and putamen in huntingtons?
Atrophy, ventricles enlarge, loss of neurons decrease Ach in putamen
WHO ICF classification for pre-manifest/prodermal huntingtons & physiotherapy aim?
Pathology, aim: advise appropriate physical activities
WHO ICF classification for early stage huntingtons & physiotherapy aim?
Impairments, aim: delay onset of mobility restriction
WHO ICF classification for mid stage huntingtons & physiotherapy aim?
Activity restriction, aim: maintain function and delay further degeneration
WHO ICF classification for late stage huntingtons & physiotherapy aim?
Participation restriction, aim: limit impact of complications
Posture of huntingtons?
Asymmetric, distorted, choreiform sit/stand postures
Gait of huntingtons?
Irregular, jerky, involuntary movement in all extremities
*ambulating can accentuate involuntary movements
*choreiform gait
What is tardive dyskinesia?
Delayed onset of sx of hyperkinetic dyskinesia characterized by involuntary/uncontrolled movement especially of the mouth, tongue, trunk, limbs
(tics, writhing movement, etc)
How does tardive dyskinesia develop?
S/E of prolonged use of antipsychotics, schizophrenia meds, depression meds, parkinsons meds, antiseizure meds, etc
*pt may be put on drug holiday to prevent/tx (3-6 mos), effect of drugs can be “tardive” (dyskinesia may appear or continue after drugs no longer taken)
What is tourettes syndrome?
Motor and vocal tics (pathology not completely understood, but elevated dopamine considered significant role)
Clinical criteria for dx of tourettes?
-Presence of both motor/vocal tics
-Tics every day for >1yr
-No remission of tics for >3mos
-Sx cause distress/impairment of function
-Age of onset <18
-Sx not d/t drugs or other condition
