Neurological Functions & Lesions

Question 1

lateral nucleus (hypothalamus)

Answer 1

hunger; stimulated by ghrelin

lesion = anorexia, failure to thrive (infants)

Question 2

ventromedial nucleus (hypothalamus)

Answer 2

satiety; stimulated by leptin

lesion = hyperphagia

Question 3

anterior nucleus (hypothalamus)

Answer 3

cooling, parasympathetic

Question 4

posterior nucleus (hypothalamus)

Answer 4

heating, sympathetic

Question 5

suprachiasmatic nucleus (hypothalamus)

Answer 5

circadian rhythm

Question 6

supraoptic and paraventricular nuclei (hypothalamus)

Answer 6

synthesize ADH and oxytocin

Question 7

preoptic nucleus (hypothalamus)

Answer 7

thermoregulation, sexual behavior; releases GnRH

failure of GnRH-producing neurons to migrate from olfactory pit => Kallmann syndrome

Question 8

ventral posterolateral nucleus (thalamus)

Answer 8

vibration, pain, pressure, proprioception (conscious), light touch, temperature

input: spinothalamic and dorsal columns/medial lemniscus

Question 9

ventral posteromedial nucleus (thalamus)

Answer 9

face sensation, taste

input: trigeminal and gustatory pathway

Question 10

lateral geniculate nucleus (thalamus)

Answer 10

vision

input: CNII, optic chiasm, optic tract

Question 11

medial geniculate nucleus (thalamus)

Answer 11

hearing

input: superior olive and inferior colliculus of tectum

Question 12

ventral anterior and ventral lateral nuclei (thalamus)

Answer 12

motor

input: basal ganglia, cerebellum

Question 13

limbic system

Answer 13

structures: hippocampus, amygdalae, mammillary bodies, anterior thalamic nuclei, cingulate gyrus

functions: feeding, fleeing, fighting, feeling, and sex

Question 14

mesocortical dopaminergic pathway

Answer 14

ventral tegmental area => cortex

decreased activity: negative symptoms (anergia, apathy, lack of spontaneity)

Question 15

mesolimbic dopaminergic pathway

Answer 15

ventral tegmental area => nucleus accumbens

increased activity: positive symptoms (delusions, hallucinations)

Question 16

nigrotriatal dopaminergic pathway

Answer 16

substantia nigra => dorsal striatum

decreased activity: extrapyramidal symptoms (dystonia, akathisia, parkinsonism, tardive dyskinesia)

Question 17

tuberoinfundibular dopaminergic pathway

Answer 17

hypothalamus => pituitary gland

decreased activity: increased prolactin (decreased libido, sexual dysfunction, galactorrhea, gynecomastia)

Question 18

lateral cerebellar lesions

Answer 18

affect voluntary movement of extremities; propensity to fall toward injured (ipsilateral) side

Question 19

medial cerebellar lesions

Answer 19

truncal ataxia (wide-based cerebellar gait), nystagmus, head tilting; bilateral motor deficits affecting axial and proximal limb musculature

Question 20

basal ganglia structures

Answer 20

striatum: putamen + caudate nucleus
lentiform: putamen + globus pallidus

Question 21

ACA-MCA watershed infarct

Answer 21

proximal upper and lower extremity weakness

Question 22

PCA-MCA watershed infarct

Answer 22

higher-order visual dysfunction

Question 23

venous sinus thrombosis

Answer 23

increased ICP (headache, seizures, papilledema, focal neurologic deficits)

Question 24

accommodation reflex: afferent and efferent limbs

Answer 24

afferent: II

efferent: III

Question 25

corneal reflex: afferent and efferent limb

Answer 25

afferent: V1 (ophthalmic nasociliary branch) efferent: bilateral VII (temporal branch)

Question 26

cough reflex: afferent and efferent limb

Answer 26

afferent: X efferent: X (also phrenic and spinal nerves)

Question 27

gag reflex: afferent and efferent limb

Answer 27

afferent: IX efferent: X

Question 28

jaw jerk reflex: afferent and efferent limb

Answer 28

afferent: V3 (sensory - muscle spindle from masseter) efferent: V3 (motor - masseter)

Question 29

lacrimation reflex: afferent and efferent limb

Answer 29

afferent: V1 efferent: VII

Question 30

pupillary reflex: afferent and efferent limb

Answer 30

afferent: II efferent: III

Question 31

prefrontal cortex lesion

Answer 31

frontal lobe syndrome: disinhibition, hyperphagia, impulsivity, loss of empathy, impaired executive function, akinetic mutism

Question 32

frontal eye fields lesion

Answer 32

eyes look **toward** brain lesion (away from side of hemiplegia); seen in **MCA** stroke

Question 33

paramedian pontine reticular formation lesion

Answer 33

eyes look **away from** brain lesion (toward side of hemiplegia)

Question 34

dominant parietal cortex lesion

Answer 34

Gerstmann syndrome: agraphia, acalculia, finger agnosia, left-right disorientation

Question 35

nondominant parietal cortex lesion

Answer 35

hemispatial neglect syndrome: agnosia of the contralateral side of the world

Question 36

basal ganglia lesion

Answer 36

tremor at rest, chorea, athetosis Parkinson disease, Huntington disease

Question 37

subthalamic nucleus lesion

Answer 37

contralateral hemiballismus

Question 38

amygdala lesion

Answer 38

bilateral lesions = Kluver-Bucy syndrome: disinhibition (hyperphagia, hypersexuality, hyperorality) seen in HSV-1 encephalitis

Question 39

mammillary bodies lesion

Answer 39

bilateral lesions = Wenicke-Korsakoff syndrome due to thiamine deficiency

Question 40

hippocampus lesion

Answer 40

bilateral lesions = anterograde amnesia seen in Alzheimer disease

Question 41

dorsal midbrain lesion

Answer 41

Parinaud syndrome: paralysis of upwards gaze, pseudo-Argyll Robertson pupils, convergence-retraction nystagmus, eyelid retraction often due to pineal gland tumors

Question 42

reticular activating system lesion

Answer 42

reduced levels of arousal and wakefulness, coma

Question 43

medial longitudinal fasciculus lesion

Answer 43

internuclear ophthalmoplegia (impaired adduction of ipsilateral eye, nystagmus of contralateral eye with abduction) seen in multiple sclerosis

Question 44

cerebellar hemisphere lesion

Answer 44

intention tremor, limb ataxia, loss of balance; ipsilateral deficits; fall toward side of lesion

Question 45

cerebellar vermis lesion

Answer 45

truncal ataxia (wide-based gait), nystagmus, dysarthria

Question 46

decorticate (flexor) posturing

Answer 46

upper limb flexion, lower limb extension lesion above red nucleus (often cerebral cortex) => overactive rubrospinal and vestibulospinal tracts

Question 47

decerebrate (extensor) posturing

Answer 47

upper and lower limb extension lesion between red and vestibular nuclei (brainstem) => overactive vestibulospinal tract worse prognosis than decorticate posturing

Question 48

ACA stroke

Answer 48

area affected: motor and sensory cortices (lower limb) contralateral paralysis and sensory loss (lower limb, urinary incontinence)

Question 49

MCA stroke

Answer 49

area affected: motor and sensory cortices (upper limb and face), temporal lobe (Wernicke area), frontal lobe (Broca area) contralateral paralysis and sensory loss (lower face and upper limb); aphasia (dominant hemisphere) or hemineglect (nondominant hemisphere)

Question 50

lenticulostriate artery stroke

Answer 50

area affected: striatum, internal capsule contralateral paralysis; **absence of cortical signs** (pure motor stroke)

Question 51

PCA stroke

Answer 51

area affected: occipital lobe contralateral hemianopia with macular sparing; alexia without agraphia (dominant hemisphere), prosopagnosia (nondominant hemisphere)

Question 52

basilar artery stroke

Answer 52

area affected: pons, medulla, lower midbrain, corticospinal and corticobulbar tracts, ocular cranial nerve nuclei, paramedian pontine reticular formation **locked in syndrome:** consciousness preserved if RAS spared; quadriplegia, loss of voluntary facial mouth, and tongue movements; loss of horizontal, **but not vertical** eye movements

Question 53

AICA stroke

Answer 53

area affected: **facial nerve nuclei** => paralysis of face, decreased lacrimation and salivation, decreased taste from anterior 2/3 of tongue area affected: **vestibular nuclei** => vomiting, vertigo, nystagmus area affected: **spinothalamic tract, spinal trigeminal nucleus** => decreased pain and temperature sensation from **contralateral body, ipsilateral face** area affected: **sympathetic fibers** => **ipsilateral** Horner syndrome area affected: **middle and inferior cerebellar peduncles** => **ipsilateral** ataxia, dysmetria area affected: **inner ear** => **ipsilateral** sensorineural deafness, vertigo

Question 54

PICA stroke

Answer 54

**lateral medullary (Wallenberg) syndrome** area affected: **nucleus ambiguus (CN IX, X, XI)** => dysphagia, hoarseness, decreased gag reflex, hiccups area affected: **vestibular nuclei** => vomiting, vertigo, nystagmus area affected: **lateral STT, spinal trigeminal nucleus** => decreased pain and temperature sensation from **contralateral body, ipsilateral face** area affected: **sympathetic fibers** => **ipsilateral** Horner syndrome area affected: **inferior cerebellar peduncle** => **ipsilateral** ataxia, dysmetria

Question 55

anterior spinal artery stroke

Answer 55

**medial medullary syndrome** area affected: **corticospinal tract** => **contralateral** paralysis (upper and lower limbs) area affected: **medial lemniscus** => decreased **contralateral** proprioception area affected: caudal medulla **(hypoglossal nerve)** => **ipsilateral** hypoglossal dysfunction (tongue deviates ipsilaterally)

Question 56

CN V motor lesion

Answer 56

jaw deviates toward side of lesion (unopposed force from opposite pterygoid muscle)

Question 57

CN X lesion

Answer 57

uvula deviates away from side of lesion (weak side collapses and uvula points away)

Question 58

CN XI lesion

Answer 58

weakness turning head to contralateral side of lesion, shoulder droop on side of lesion

Question 59

CN XII lesion

Answer 59

LMN lesion; tongue deviates toward side of lesion (weakened tongue muscles on affected side)