Cerebral Cortex

Question 1

What layer of the neocortex give rises to the axons that form corticospinal and corticobulbar tracts?

Answer 1

Internal pyramidal layer

Question 2

What is the presentation of anterior cerebral artery occlusion?

Answer 2

• spastic paralysis and anesthesia of contralateral lower limbs
• urinary incontinence (usually bilateral lesion)
• Transcortical apraxia of the left limbs
• frontal lobe abnormalities

Question 3

Presentation of the middle cerebral artery occlusion

Answer 3

• spastic paralysis of contralateral lower face and upper limb
• anesthesia contralateral face and upper limb
• aphasia (broca, Wernicke, or conduction, Gerstman sx) (left middle cerebral artery branches affected)
• left-sided neglect (right middle cerebral artery branches affected, no dominant hemisphere)
• contralateral superior quadrantanopsia (Meyer’s loop)
• gaze palsy (brodmann 8)

Question 4

Presentation of posterior cerebral artery occlusion

Answer 4

Homonymous hemianopia of contralateral visual field with macular sparing.
*alexia without agraphia may occur if dominant hemisphere involved - splenium involved

Question 5

Most common site of aneurysm

Answer 5

When anterior communicating artery joins an anterior cerebral artery

Question 6

Initial presentation of an aneurism of internal carotid, and first nerve of cavernous sinus involved when expand laterally.

Answer 6

• compression temporal axons or lateral aspect of chiasm ▶️ ipsilateral nasal hemianopia
• VI CN ▶️ internal strabismus

Question 7

Features of a embolic infarct and most vulnerable artery to them

Answer 7

• hemorrhagic/red infarct

- middle cerebral artery

Question 8

What mechanism can cause a “watershed” areas and involvement of deep cortical layers in brain infarct?

Answer 8

Hypotension

Question 9

What sites and type of infarct do you expect in hypertension patients?

Answer 9

• basal ganglia, internal capsule and pons

- lacunar infarct

Question 10

Mention 5 predisposing factors to aneurysm rupture? Presentation

Answer 10

• Marfan syndrome, ehlers-danlos type 4, adult polycystic kidney disease, hypertension, smoking
• subarachnoid hemorrhage

Question 11

What area of brain is possible damage when you have a inability to make voluntary eye movement toward contralateral side?

Answer 11

Lesion of the frontal eye field (brodmann 8)

- result: conjugate slow deviation of the eyes toward the side of the lesion (intact side make it)

Question 12

Signs and symptoms is lesion in prefrontal area

Answer 12

• difficult concentrate, easily distracted, lack of initiative, foresight and perspective
• apathy (severe emotional indifference), abulia
• slow intellectual faculties, slow speech, decreased participation in social interactions
• suckling or grasp reflexes

Question 13

Lesion in Broca area, brodmann 44 and 45. Signs and symptoms.

Answer 13

• Broca (expressive) aphasia
• Agraphia (often affected in all aphasias)
• they can understand but lack of ability to verbalize their thoughts orally or writing

Question 14

Findings in clinical presentation of lesion at left (dominant) hemisphere at Brodmann area 5,7 (posterior parietal association cortex)

Answer 14

• apraxia (bilateral)
• astereognosia (contralateral)
• apraxia results of loss of input to premotor cortex (area 6)

Question 15

Inability to comprehend spoken and reading (alexia) language (base extend of lesion). Patient paraphasic.

Answer 15

Wernicke aphasia (receptive)

Question 16

Clinical presentation of the lesion at angular gyrus (area 39) in dominant hemisphere. Cause

Answer 16

• Gerstman syndrome: alexia, Agraphia, but understand spoken language. Acalculia, finger agnosia, right-left disorientation
• infarction of the left MCA

Question 17

What structure is damage in conduction aphasia? Which are the signs?

Answer 17

• superior longitudinal fasciculus (arcuate fasciculus): connect Wernicke and Bronca areas. Inability to send information between them
• verbal output fluent, but many paraphrases and word-finding pauses, no repeat words or verbal commands, poor object naming, frustration

Question 18

Patient with apraxia, no motor weakness, inability to execute commands to move left arm, understanding it, can execute commands to move right arm. Name of the description and cause.

Answer 18

• Transcortical apraxia (disconnect syndrome)
• infarct of the anterior cerebral artery ▶️ lesion at corpus callosum

*disconnection of Wernicke area (left) from right primary motor cortex. Execute command with right arm because Wernicke area at left hemisphere can communicate with ipsilateral primary motor cortex without corpus callosum

Question 19

What is the result of a wide spread lesion in areas 7, 39, 40 in no dominant right parietal lobe?

Answer 19

• asomatognosia: neglect contralateral half of body ▶️ no dress, undress, wash, etc. deny existence of things at left visual side (they can see)
• anosognosia: deny the deficit

Question 20

Cause of homonymous contralateral hemianopia with macular sparing, what cortical area involve?

Answer 20

• infarct of a branch of posterior cerebral artery

- primary visual cortex, brodmann 17 (striate)

Question 21

What lesion may cause achromatopsia, prosopagnosia and visual agnosia?

Answer 21

• inferior part of temporal lobe (area 20, 21)

* visual association cortex: form and color

Question 22

Lesion at parietal lobe in areas 18, 19 (visual cortex - extrastriate, visual association cortex)

Answer 22

Deficit in perceiving visual motion and depth

*unaffected visual fields, colors, reading.

Question 23

Patient with Alexia without Agraphia, unable to read and to name colors (color anomia, curious), can write, and associated with homonymous hemianopia with macular sparing, where is the lesion? And cause of it.

Answer 23

• left occipital cortex (anterior part) and splenium of corpus callosum
• infarction of left posterior cerebral artery
• impair visual info from intact right occipital cortex (left visual field) to reach language comprehension center in left side ▶️ not understand what you see

Question 24

Symptoms in a lesion of primary auditory cortex

Answer 24

• Little loss auditory sensitivity

- some difficult localizing sounds in contralateral sound field

Question 25

What clinical presentation do you expect in a hypertensive stroke involving lenticulostriate branch of MCA?

Answer 25

• contralateral spastic paralysis, weakness, anesthesia upper, lower limbs, trunk and face
• irrigate genu and posterior limb of internal capsule ▶️ corticospinal, all somatosensory thalamocortical projections and corticobulbar tracts

Question 26

Which are the disconnect syndromes and their damage structures?

Answer 26

• conduction aphasia - superior longitudinal fasciculus (arcuate)
• Transcortical aphasia - corpus callosum
• alexia without agraphia - splenium of corpus callosum

Question 27

When occur a sensory dysphrosodia?

Answer 27

• Wernicke area lesion (22) in no dominant hemisphere (right)
• MCA stroke

Question 28

What happen if premotor cortex (brodmann 6) is damaged?

Answer 28

• apraxia: unable to perform movements in correct sequence
• no weakness and individual movements normal
• planning motor activities (function of premotor cortex)

Question 29

Second most common site of cerebral aneurysm, what sign is frequently associated?

Answer 29

• posterior communicating artery

- III CN palsy