BB physiology Flashcards
Structural changes in epilepsy
Loss of CA2 and 3 cells in the hippocampus
Temporal lobe and hippocampal sclerosis
Causes of secondary epilepsy
Craniotomy Brain injury Stroke Aneurysm Tumour CNS infection
Cellular mechanisms of epilepsy
Abnormal neuronal excitability
Increased excitation
Decreased inhibition
What is the paroxysmal depolarising shift?
Depolarisation of the membrane causes a sustained burst of action potentials involving activation of NMDA receptors
Which drugs are used for tonic clonic seizures?
Carbamazepine
Soldium valporate
Lamotrigine
Which drugs are used for absence seizures?
Ethosuzimide
Sodium valprotate
Which drugs are used for myoclonic seizures?
Sodium valprotate
Clonazepam
Levatiracetam
Which area is used for DBS in epilepsy?
Anterior nucleus of the thalamus
What diet can be used for epilepsy?
Ketogenic diet
What is optic neuritis?
Inflammation of the optic nerve
Seen in MS
What is internuclear ophthalmoplegia?
Damage to the MLF resulting in impaired adduction of the eye during head rotation
Seen in MS
What is Lhermitte’s symptom?
Electric shock sensation down the back of the leg
What is Uhthoff’s phenomenon?
Worsening of neurological symptoms in increased temperature due to increased velocity of nerve conduction
Where are MS lesions commonly found?
Corpus callosum Periventricular Cervical spinal cord Optic nerve Brainstem and cerebellar connections
MS lesions enhance with what?
Gadolinium
What does the McDonald’s criteria state for MS diagnosis?
Presence of neurological symptoms
Dissemination in time
Dissemnination in space
Exclusion of other causes
HLA molecule implicated in MS
HLA-DRB1
No evidence of disease activity in MS
No relapses
No increase in disability
No new or active lesions on MRI
Which artery is most commonly occluded in the posterior circulation?
PCA
3 layers of the cerebellar grey matter?
Outer molecular layer = axons and densrites
Single middle Purkinje cell layer
Inner thick granule layer
What is within the SCPs?
Output fibres to the thalamus and cortex
What is within the MCPs?
Input fibres from the contralateral cerebral cortex and cranial nerve nuclei
What is within the ICPs?
Input fibres from the spinocerebellar tract
Ventral SCT
State of reflexes and interneurones
Decussates twice
Dorsal SCT
Proprioception
No decussation
Where is the fastigial nucleus found?
Vermis
Where is the interpose nucleus found?
Anterior lobe
What males up the interpose nuclei
Globose
Emboliform
Where is the dentate nucleus found?
Posterior lobe
What is the nucleus for the flocculonodular lobe?
Lateral vestibular nucleus
What tracts does the spinocerebellum use?
Lateral vestibulospinal
Reticulospinal
Which lobe is the spinocerebellum?
Anterior lobe
Vermis
Which lobe is the cerebrocerebellum?
Posterior
Which lobe is the vestibulocerebellum?
FN
What are the inputs and outputs of the cerebrocerebellum?
Input = MCP Output = SCP
Medial vs lateral vestibulospinal tracts
Medial = head and neck Lateral = postural muscles
What does medulloblastoma commonly cause?
FN syndrome
Symptoms of FN syndrome
Nystagmus
Ataxic gait
Fall towards side of lesion
Axial hypotonia
Symptoms of anterior lobe syndrome
Incoordination of the limbs Ataxic gait Hypotonia Dysdiadochokinesia Altered reflexes
Neocerebellar syndrome symptoms
Dysmetrria
Intention tremor
Slurred speech
Loss of eye scanning
Which cerebellar syndrome does alcoholism cause?
Anterior lobe syndrome
What does the premotor cortex do?
Integrates information from the more anterior parts of the frontal lobe and forms motor programs that are sent to the primary motor cortex
What does damage to the premotor cortex cause?
Apraxia
What does damage to the FEFs produce?
Problems with cognitive eye movements
Saccades, smooth pursuit, vergence
What does the dorsalprefrontal cortex do?
Planning of movements where we evaluate possible actions
Executive function
What does the orbitofrontal cortex do?
Inhibition of motor responses associated with the limbic system
Where does the CST decussate?
Spino-medullary junction
What does the reticulospinal tract drive?
Sympathetic preganglionic neurones
Phrenic nerve
Where does the rubrospinal tract originate from?
Red nucleus
Where does the tectospinal tract originate from?
Superior colliculus
What does the tectospinal tract control?
Reflex head movements in response to auditory and visual stimuli
Arms in decorticate vs decerebrate
Decorticate = arms adducted and flexed Decerebrate = arms adducted and extended
Which lamina is innervated by Ad fibres?
V
Which lamina is innervated by C fibres?
I and some interneurones in II
What substances do peptidergic C fibres release?
Substance P
CGRP
Anterior spinothalamic pathway
Mostly Ad fibres From lamina V and IV Fast pain Discrimination and localisation Projects to VPL, VPM, VPI, CL
Lateral spinothalamic pathway
Mostly C fibres From lamina I Slow pain Emotionally punishing aspects of pain Projects to MDvc, POs, VMpo --> anterior cingulate cortex and insula
Input to BG
Cortex –> striatum
Via glutamate
Output from BG
GPI
SNr
–> VA/VL thalamus
Via GABA
Input to medium spiny neurones
Cortical via spines
SNpc –> spines, dendritic shafts, cell body
Cardinal signs of PD
Tremor at rest
Rigidity
Bradykinesia
Loss of postural reflexes
Cardinal signs of Huntingdon’s
Hyperkinesis
Ballismus = jerky
Athetosis = smooth
APOE in AD
E4 = greatest risk E2 = protective
Amyloidogenic pathway
Beta and gamma secretases
CSF markers of AD
Raised Tau
Decreased beta amyloid
Signs of subfalcine herniation
Leg weakness
Signs of transtentorial herniation
CN III damage
Midbrain damage
Often fatal
Signs of tonsillar herniation
Reduced respiratory drive
Unconscious
Death
Rostral vs caudal ACC
Rostral = actions in response to pain Caudal = registers quality of pain
Posterior cingulate cortex function
Visuo-spatial memory
Orbitofrontal cortex function
What acts to take in response to pain
Symptoms of Wernicke-Korsakoff syndrome
Anterograde amnesia
Some retrograde amnesia
Confabulation
Apathy
Kluver Bucy syndrome
Bilateral removal of amygdala
Psychic blindness
Oral tendancies
Altered sexual behaviour emotional changes
Pre-synaptic changes in LTP
Early = increase in glutamate release in response to anterograde transmitters (NO, CO) Late = increase in number of glutamate release sites
Post-synaptic changes in LTP
Early = increased number and sensitivity of AMPA receptors Late = increased number of synapses
NMDA antagonists
Memantine = near to where Mg binds Ketamine = allosteric site
Persistent vs permanent vegetative state
Persistent = >1 month Permanent = >1 year
DBS for persistent vegetative state
Thalamus
Drugs for reduced consciousness
Amantadine
Zolpidem
Chemicals in the blood affecting sleep
Promote awake - ghrelin - low glucose Promote sleep - CCK - adenosine
Where are sleep chemicals detected?
Preoptic nuclei
Where are diurnal rhythms detected?
Suprachiasmatic nucleus
Where do the preoptic and suprachiasmatic nuclei project?
Tuberomamillary nucleus
What does the tuberomamillary nucleus release?
Histamine
Where are orexins released from?
Posterior thalamus
Which NT system is active during REM sleep/
ACh
Which NT is thought to be involved in remembering dreams?
NA
Time limit for thrombolysis
4.5 hours
Percent of strokes that are ischaemic
70-80%
TOAST stroke classification
1 = large artery atherosclerosis 2 = cardioembolism 3 = small vessel occlusion 4 = other origin 5 = undetermined
ABCD2 score for TIA
Predicts risk of stroke A = age>60 (1) B = BP>140/90 (1) C = clinical features --> hemiparesis (2), speech alone (1) D = duration --> <1h (1) >1h (2) D = diabetes (1) Hospitalise if >4
Utricle
Horizontal tilting
Detect side to side movement and acceleration
High activity lying down
Saccule
Vertical tilting
Detect activity forwards and backwards and up and down
High activity standing up
Endolymph vs perilymph
Endo = high K+, low Na+ Peri = high Na+, low K+
What do the semicircular canals detect?
Angular acceleration
How is each semicircular canal activated?
Lateral = side to side rotation Anterior/superior = neck flexion Posterior/inferior = neck extension
Which was around are the striola directions in the otolithic organs?
Utricle = towards striola Saccula = away from striola
What does the striola divide the otoliths into?
Utricle = medial and lateral halves Saccule = anterior and posterior halves
Which direction will nystagmus occur with warm irrigation?
Same side
Which direction will nystagmus occur with cold irrigation?
Opposite
BPPV
Benign paroxysmal positional vertigo
Otoliths displaced
Can be detected by Hallpike manoeuvre
Meniere’s disease
Dysfunctional production of endolymph
Can lead to rupture
