Block 6 - Neuro

Front 1

Which receptors are associated with with which types of fibres?

Back 1

* Muscle spindles: Ia (Aα)
* Golgi tendon organs: Ib (Aα)
* Most tactile: II (Aβ, Aγ)
* Temp, pain, crude touch: III (Aδ), IV (C)

(A = large myelinated, C = small unmyelinated)

Front 2

What are the 4 types of tactile sensory receptors?

Back 2

* Meissner (touch - hairless skin)
* Pacinian (deep press / vibration)
* Ruffini (stretch)
* Merkel (touch - hair)

(All Aβ (II) fibres)

Front 3

What is the organization of the stretch and flexor reflexes?
Which reflexes involve interneurons?

Back 3

* Flexor reflex: sensory receptor (skin) --> excitatory (flexor) and inhibitory (extensor) interneurons --> α motor cells

* Golgi tendon organ (inverse stretch reflex): Golgi tendon organ --> inhibitory interneurone --> α motor cell

Front 4

What is the function of the γ reflex looop and the Golgi tendon organ reflexes?

Back 4

* γ reflex loop: set muscle tone by modifying stretch reflex

* Golgi tendon organ: muscle lengthening reaction to prevent excessive tension

Front 5

What is the mechanism of glutamate toxicity?

Back 5

* ↓ATP --> loss of Na+ gradient
--> ↑release of glutamate
--> activation of NMDA receptors
--> influx of Ca2+
--> cell damage from excess Ca2+

Front 6

What are the effects of spinal shock?

Back 6

* Loss of reflexes (somatic & autonomic)
* Flaccid paralysis
* Loss of bladder & bowel tone (bladder distension, paralytic ileus)
* Loss of SYMP vascular tone (↓BP and ↓HR)

("Warm & dry" shock)

Front 7

What spinal roots are tested by the common clinical reflex tests?

Back 7

Biceps (C5 / C6)
Brachioradialis (C6)
Triceps (C7)
Patellar (L4)
Achilles (S1)

Front 8

What are the layers of the retina?

Back 8

* Pigment epithelium (posterior)
* Photoreceptors
* Bipolar, horizontal, amacrine cells
* Ganglion cells
- magnocellular (motion)
- parvocellular (color, form)

Front 9

Describe the nerve supply to the lens and zonular apparatus

Back 9

PARA
Ciliary ganglion --> sphincter pupillae and ciliary muscle

SYMP
Cervical symp ganglia --> dilator pupillae

SENSORY
V1 via ciliary ganglion

Front 10

What is the arterial supply to the eye?

Back 10

Opthalmic a.
--> central retinal a. (inner retina)
--> ciliary aa. (choroid / outer retina, ciliary body, iris)

Front 11

Describe the venous drainage of the eye

Back 11

* Superior ophthalmic v. --> cavernous sinus

* Inferior ophthalmic v. --> pterygoid venous plexus

* Central retinal v. --> cavernous sinus

Front 12

What is the main treatment for MS? (2)

Back 12

* IV methylprednisolone (for acute attacks)

* IFN-β (reduce MHC II, T cell proliferation, TNF production)

Front 13

What are the components of active and inactive plaques in MS?

Back 13

Active plaques:
* Macrophages & lymphocytes
* Ongoing myelin breakdown

Inactive plaques:
* No myelin, ↓axons
* ↓oligodendrocytes
* ↑astrocytes

Front 14

What are the two types of nerve degeneration?

Back 14

* Wallerian degeneration (distal end degenerates rapidly after nerve is severed)

* Axonal degeneration (axons die back slowly because of unmet metabolic demands, e.g., diabetes)

Front 15

Which nucleus is involved in the pupillary reflex?

Back 15

Pretectum
(connects bilaterally to E-W nucleus)

Front 16

What is the limbus and what is its significance?

Back 16

* Boundary zone between cornea and sclera
* Contains main outflow pathway for drainage of aqueous humor

Front 17

What do the terms "striatum" and "lenticular nucleus" refer to?

Back 17

Striatum = caudate + putamen

Lenticular nucleus = putamen + GP

Front 18

What are the pathological features of Parkinson's disease?

Back 18

* Loss of dopaminergic neurons in SN and LC (--> depigmentation)

* Lewy bodies composed of α-synuclein filaments

Front 19

In Parkinson's, which areas of the brain are responsible for "shakes" vs. "statues"?

Back 19

Shakes: thalamus

Statues: pedunculopontine nucleus

Front 20

What are the categories of positive movement disorders ranked by increasing speed?

Back 20

* Dystonia (distorted contractures)
* Athetosis (slow, irregular writhing)
* Chorea (unpredictable, fluid)
* Ballismus (flinging, large-amplitude, often due to subthal. lesion)
* Tics (sudden, brief)
* Myoclonus (shock-like, jerk)
* Tremor

Front 21

What are pharmacological treatments for Parkinson's? (6)

Back 21

* L-Dopa + decarboxylase inhibitor
* MAOB inhibitors (e.g., Selegeline)
* COMT inhibitors
* DA agonists (e.g., bromocriptine)
* Anticholinergics (for tremor)
* Amantadine

Front 22

What is the pathology of chorea?

Back 22

↓GABA (Enk) cells in CPu

--> ↑indirect pathway (↑DA, ↓ACh)

--> dyskinesia, hypotonia

Front 23

What are the causes of chorea?

Back 23

* Huntington's
* Sydenham (post-rheumatic fever, pregnancy)
* Autoimmune (e.g., SLE)
* Blood disorders
* L-dopa induced

Front 24

What are the location, connections, and functions of the archicerebellum / vestibulocerebellum?

Back 24

* Location: flocculonodular lobe

* Input: cortex via pontine nuclei
* Output: vestibular nuclei

* Function: vestibulo-ocular control

Front 25

What are the location, connections, and functions of the neocerebellum / cerebrocerebellum?

Back 25

* Location: lateral hemispheres

* Input: cortex via pontine nuclei
* Output: dentate n. --> thalamus, red n. --> cortex

* Function: motor planning

Front 26

What are the location, connections, and functions of the paleocerebellum / spinocerebellum?

Back 26

* Location: vermis & paravermal zone

* Input: spinocerebellar tract
* Output: (1) thalamus & red n. --> limb muscles (2) reticulospinal & vestibulospinal tracts --> axial muscles

* Function: continuous control of posture & movement

Front 27

What types of cells are in the cerebellum?

Back 27

* MOSSY FIBRES and CLIMBING FIBRES activate PURKINJE CELLS, which carry all outputs from the cerebellum

* GRANULE CELLS between climbing fibres and Purkinje cells

* BASKET, STELLATE, and GOLGI CELLS are inhibitory local cells

Front 28

What are the mesolimbic and mesocortical pathways?

Back 28

* VTA -->+ PFC
* VTA -->- LS
* PFC negatively inhibits VTA and LS

* Overactivity of LS --> +ve symptoms
* Underactivity of PFC --> -ve symptoms

Front 29

What are the symptoms of psychosis?

Back 29

* POSITIVE SX: hallucinations, delusions, disorganization, loss of insight
NEGATIVE SX: alogia, affective blunting, amotivation, asociality
* COGNITIVE IMPAIRMENT esp. verbal
* EXCITEMENT / AGGRESSION
* ANXIETY / DEPRESSION

Front 30

Describe the different types of dopamine receptors

Back 30

D1, D5: post-synaptic excitatory

D2, D3, D4: inhibitory
(D2: presynaptic)

Mechanism: GCPR --> adenylate cyclase --> ↑cAMP

Front 31

What pathways account for the side effects of antipsychotic medications that antagonize D2 receptors?

Back 31

* Nigrostriatal pathway
- SNC --> CPu
- movement side effects (e.g., dyskinesia)

* Tuberoinfundibular pathway
- hypothalamus --> pituitary
- endocrine side effects (e.g., ↑prolactin)

Front 32

What are the side effects of antipsychotics?

Back 32

* Movement disorders (parkinsonism, TD)
* ↑prolactin --> gynaecomastia
* Hypotension (α-block)
* Sedation (H1-block)
* ↑weight
* Jaundice (1st gen)
* Agranulocytosis (esp. clozapine)
* Cardiotoxicity

Front 33

What are the stages of differentiation of the neural tube?

Back 33

(1) Prosencephalon
* Telencephalon --> cerebrum
* Diencephalon --> thalamus

(2) Mesencephalon --> midbrain

(3) Rhombencephalon
* Metencephalon --> pons & cerebellum
* Myelencephalon --> medulla

Front 34

What is the mechanism of the following antiepileptic drugs:
* carbamazepine?
* valproate?
* phenytoin?

Back 34

* Carbamazepin: activate adenosine receptors (--> ↓glutamate), ↓nerve impulse conduction (via Na+ channels)

* Valproate: ↓GABA metabolism

* Phenytoin: ↓nerve impulse conduction by blocking Na+ channels

Front 35

What are the signs of an AICA stroke?

Back 35

(dorsal pons)
* Vertigo, vomiting, falling to one side (internal auditory a.)
* Nystagmus (Ves)
* Loss of sensation ipsi face (Vp, Vsp, Vmes)
* Paralysis ipsi face (VII)
* Hearing loss ipsi (VIII)

Front 36

What are the signs of a PICA stroke?

Back 36

(Dorsal lateral open medulla)
* Loss of pain/temp ipsi face (Vsp) and contra body (STt)
* Dysphagia, dysarthria (NAm)
* Vertigo & nystagmus (Ves)
* Ipsi ataxia (cerebellum)
* Ipsi Horner's syndrome (SYMP)

Front 37

What structures in the brainstem control respiration?

Back 37

* Retrotrapezoid nucleus (central [H+] chemoreceptors in rostral medulla / caudal pons)

* Dorsolateral pons (regulate inspiratory neurons)

* Medullary resp. center (inspiratory & expiratory neurons)

Front 38

What structures are affectged by strokes to the following arteries?
* Anterior spinal a.
* Vertebral a.
* SCA
* Paramedian/basal arteries of midbrain

Back 38

* ASA: pyramids, ML, XII

* Vertebral a: similar to PICA stroke

* SCA: cerebellum

* Paramedian/basal arteries in midbrain: corticospinal tracts, corticobulbar tracts, III

Front 39

What are the functions of the following brainstem nuclei?

Back 39

* DMX: PARA to thorax, gut

* SolT: rostral taste, caudal visceral sensory

* NAm: visceral motor, motor to pharynx / larynx / palate

Front 40

How is BP controlled in the brainstem?

Back 40

* Baroreceptors via IX,X --> SolT
--> CVLM
--> RVLM (tonically active)
--> SYMP neurons in spinal cord

Front 41

What are the effects of COX1 and COX2 on platelet aggregation?

Back 41

Platelets: COX1 --> thromboxane A2 (pro-aggregatory)

Endothelium: COX2 --> prostacyclin (anti-aggregatory)

Front 42

What is the role of MRIs in acute stroke management?

Back 42

* Diffusion-weighted MRI to detect & localize acute ischaemic brain lesions

* Perfusion MRI to demonstrate ischaemic penumbra

Front 43

What investigations should be ordered to diagnose meningitis?

Back 43

* FBC (↑Neut vs. ↑Lymph)

* CT Head (purulence in subarachnoid space, no intracranial displacement)

* LP
- Bacterial: ↑Neut, ↓Gluc, ↑Protein
- Viral: ↑Lymph, N Gluc, Protein may be ↑

Front 44

What are the contraindications for lumbar puncture?

Back 44

* ↑ICP (headache, vomiting, papilloedema)

* Focal neurological signs

Front 45

What are the common microbial causes of meningitis and the corresponding choice of antibiotics?

Back 45

0-3 MONTHS
* E. Coli, Listeria, Group B Strep
* Gen 3 cephalosporin + ampicillin (for Listeria)

> 3 MONTHS
* HIb (kids), S. Pneumoniae, N. Meningitidis
* Gen 3 cephalosporin + Vancomycin if penicillin-resistant strep

Front 46

Compare the clinical presentations of meningitis and encephalitis / abscess

Back 46

* Meningitis: fever, headache, neck stiffness

* Encephalitis + abscess: fever, headache, focal neurological signs

Front 47

For which antibiotics are therapeutic CSF levels not achievable?

Back 47

* Aminoglycosides (e.g., gentamycin)

* Gen1 & Gen2 cephalosporins

(Penicillins, Gen3 cephalosporins, carbapenems, vancomycin OK in high IV doses)

Front 48

How do the semicircular canal structures detect angular forces?

Back 48

Movement of endolymph detected by hair cells of *crista* of ampulla

Front 49

How are linear forces detected by the otolith structure?

Back 49

Movement of otolith particles stimulate hair cells in *maculae* in utricle and saccule

Front 50

How are horizontal eye movements coordinated?

Back 50

Cortex + tectum + cerebellum
--> pontine reticular formation
--> VIn
--> MLF
--> IIIn, IVn, Ves

Front 51

What structures specifically coordinate saccades and pursuit movements?

Back 51

* Saccades: frontal eye fields (premotor cortex)

* Pursuit: Retina & visual cortex --> superior colliculus, pretectum

(Both pathways --> PRF --> VIn)

Front 52

What type of molecules readily cross the BBB?

Back 52

* Lipid-soluble molecules
e.g., O2, CO2, ethanol, nicotine, diazepam, caffeine (NOT penicillin)

(glucose requires GLUT1 transporter)

Front 53

In lesions of cerebral hemisphere, in which direction is gaze preference typically?

Back 53

* Cerebral hemisphere lesion --> impair eye movements in C/L direction

--> gaze preference toward the side of the lesion

Front 54

How do Vp and Vsp inputs project to the thalamus?

Back 54

Vp --> C/L trigeminal lemniscus --> VPM of thalamus

Vsp inputs descend in spinal tract --> synapse in Vsp --> ascend in C/L trigemino-thalamic tract --> VPM of thalamus

Front 55

How is the spinal tract of V organized?

Back 55

* V1 ventral, V3 dorsal

* Nose region synapses first, crown of head and dura last

(damage to Vsp --> ring-shaped sensory loss)

Front 56

What territories are supplied by the anterior choroidal artery?

Back 56

* Choroid plexus of inferior horn of lateral ventricle
* Part of hippocampal formation
* Amygdala
* Part of basal ganglia
* Internal capsule behind lentiform nucleus

Front 57

What groups of vessels supply the basal ganglia and thalamus?

Back 57

(anterior to posterior, roughly)
* ACA -- perforating aa.
* MCA -- lenticulostriate aa.
* AChA
* PCA -- thalamoperforating aa.
* PCA -- thalamogeniculate aa.

Front 58

What are the features of a tension headache?

Back 58

* Common
* Triggered by stress
* Slow onset, persistent
* Band-like, non-pulsating
* Temples, back of head & neck, bilateral
* No nausea, vomiting, photophobia

Front 59

Which layers of the cortex communicate with the thalamus?

Back 59

* Layer IV: input from thalamus

* Layer VI: output to thalamus

Front 60

In what populations are low-grade astrocytomas and glioblastoma multiforme typically found?

Back 60

* Low-grade astrocytoma: young adults

* GBM: 50-70 year olds,

Front 61

What is a common site for Schwannomas?

Back 61

* Between cerebellum & pons

(Sx: tinnitus, hearing difficulties, abnormal facial sensation)

Front 62

What are the specific attentional centers?

Back 62

* Superior colliculus (shift attention to site of action in visual fields)
* Thalamus (filters input to cortex)
* Parietal association cortex
* Dorsolateral prefrontal cortex and anterior cingulate cortex (suppress distractors, focus attention)

Front 63

What is the Papez circuit?

Back 63

Entorhinal cortex
--> hippocampal formation
--> (via fornix) mammillary bodies
--> anterior thalamus
--> cingulate cortex
--> back to entorhinal cortex

Front 64

What are the pathological features of Alzheimer's disease?

Back 64

* Cortical atrophy

* Neuritic plaques (Aβ core) (Aβ cleaved from APP by γ-secretase)

* Neurofibrillary tangles (hyperphosphorylated tau protein -- best correlation with dementia)

Front 65

Which genes are associated with Alzheimer's disease?

Back 65

* Amyloid protein precursor (APP)
* Presenilin
* (Trisomy 21)
* Apolipoprotein allele E4

Front 66

What are the 2 main pharmacological treatments for dementia?

Back 66

* Cholinesterase inhibitors
* NMDA antagonists

Front 67

What are common types of dementia apart from Alzheimer's?

Back 67

* Vascular dementia
* Dementia with Lewy bodies (fluctuating, Parkinsonism, visual hallucinations)
* Frontotemporal dementia (behavioral changes, aphasia, rel. younger populations, tau / TDP43)
* Alcohol-related dementia

Front 68

What are the main types of primary muscle disease?

Back 68

* Muscular dystrophy
* Myotonic dystrophy (ptosis, frontal balding)
* Polymyositis (autoimmune)
* Dermatomyositis (rash over eyelids)
* Inclusion body myositis (Alzheimer-like)
* Mitochondrial mypothies (statins)

Front 69

What are the signs of a stroke to the MCA superior division vs. MCA inferior division?

Back 69

MCA SUPERIOR:
* C/L face & upper limb weakness +/- sensory loss
* Broca's aphasia (L)
* C/L hemineglect (R)

MCA INFERIOR:
* C/L visual field defect
* Wernicke's aphasia (L)
* Profound hemineglect (R)

(i.e., MCA inf. hemineglect not as bad if stroke on language side of brain)

Front 70

What are the features of delirium?

Back 70

* Impairment of attention
* Cognitive / behavioral deficits
* Acute / subacute time course
* Fluctuations in clinical state (freq. worse at night)

Front 71

What are the ascending dopamine pathways in the CNS?

Back 71

* Mesolimbic: VTA --> N. Accumbens, amygdala, limbic areas
(overactive in schizo.)

* Mesocortical: VTA --> DLPF cortex
(underactive in PD, schizo.)

Front 72

Describe the BDNF theory of mental disease

Back 72

Chronic stress --> ↑corticosteroids
--> ↑Glut responsiveness, ↑NMDA activity
--> Ca toxicity, ↓cAMP-CREB-BDNF
--> loss of neurotrophin support
--> neuron damage, cell death, dendritic loss

Front 73

What is the mechanism of action of the following antidepressants:
* TCAs?
* Monoamine oxidase inhibitors?
* SSRIs?

Back 73

* TCAs: inhibit NA & 5HT reuptake

* MAOIs: ↓metaboilsm of free NA & 5HT in nerve terminals

* SSRIs: inhibit 5HT reuptake via 5HT transporter

Front 74

What areas of the cortex form part of the limbic system, and what is the role of each of these areas?

Back 74

* ANTERIOR CINGULATE: visceral premotor, emotionally-charged tasks, ventral affective, dorsal cognitive
* ORBITAL PREFONTAL: emotional decision-making
* VENTRAL PREFONTAL: activity ↑in happiness, ↓in depression
* INSULA: visceral sensory & taste, maps emotions --> visceral state ("gut feeling")

Front 75

What is the role of the amygdala in the limbic system?

Back 75

* Input: sensory, cortical, hippocampal

* Function:
- emotion-related learning
- emotional response to stimuli (esp. fear)

Front 76

What are the main functional areas of the thalamus?

Back 76

* VP: somatosensory (VPM = head, VPL = body)
* VA: cerebellum & basal ganglia input, output to motor cortex
* ANTERIOR: input from mamillary bodies, emotional processing
* MEDIAL: prefrontal cortex & amygdala, pain processing, personality, memory
* PULVINAR: attention

Front 77

What brain areas are affected by Alzheimer's disease?

Back 77

* Medial temporal lobe initially
* Followed by limbic and neocortical areas (esp. association cortex)

Front 78

What are general (non-toxic) side effects of TCAs?

Back 78

* Muscarinic antagonism: dry mouth, blurred vision, constipation, sinus tachycardia
* alpha-1 antagonism: postural hypotension
* Histamine antagonism: sedation
* 5-HT antagonism: sexual dysfunction, weight gain