Lecture 43 - Cortex

Question 1

The _______ sulcus divides the Occipital lobe into an Upper and lower cortex (One gyrus above and One gyrus below the Calcarane sulcus.

What are the names of each of those Gyri, and how do they correspond to the visual field?

Answer 1

Calcarane sulcus

Upper Gyrus –> Cuneus

Lower –> Lingual

The Upper (Cuneus) corresponds to the Lower visual field, while the Lower (Lingual) corresponds to the Upper visual field.

Question 2

Why don’t patients with BI lose hearing?

Answer 2

Each ear projects BILATERALLY to the Auditory cortices.

Question 3

Cerebral Lateralization refers to the different processes that occur in either the dominant or non-dominant hemisphere.

Language, Praxis, and Detailed Analytical Abilities –> ________ (dominant or non-dominant?)

Spatial Attention, Complex visual-spatial abilities, Appreciation of overall gestalt (big picture) –> ________ (dominant or non-dominant?).

Answer 3

Dominant

Non-dominant

Question 4

In General, the ______ hemisphere is dominant in most people. With that in mind, a good way to think about which hemisphere is responsible for which processes is

Literal and Representative, where the L = Left and R = Right.

Answer 4

Left hemisphere (Literal)

Question 5

_______ area is in the Superior 2/3 of the Temporal lobe, and it is responsible for Language sensory input and Lexicon (association of word sounds and spelling with meaning).

_______ area is in the Inferior Frontal Gyrus is responsible for the Motor aspects of Language AND Syntax (sentence structure, tense, and grammar.)

These areas are connected by the ________ Fasciculus.

Answer 5

Wernicke’s area

Broca’s area

Arcuate Fasciculus

Question 6

The Arcuate Fasciculus is a _____ matter tract, deep to the cortex, and it is responsible for _______. When ONLY this area is affected –> _______ Aphasia.

Answer 6

White matter

Repetition

Conduction Aphasia

Question 7

The _____ ______ allows the Dominant and Non-dominant Hemispheres to “talk,” so damage here will result in misalignment of Emotional aspects of Speach (Non-dominant side) and the Comprehension and Production of speach (Dominant side)

Answer 7

Corpus Collosum

Question 8

Damage to the _____ _____, resulting in impaired ______, is necessary for TRUE Wernicke’s and Broca’s Apashia.

Answer 8

Arcuate Fasciculus

Repetition

Question 9

Anomia is typically a chartacteristic of _______ aphasia.

Answer 9

Broca’s

Question 10

When Wernicke’s area is affected but Arcuate Fasciculus is NOT affected –> ________ Sensory Aphasia.

When Broca’s Area is affected but Arcuate Fasciculus is NOT affected –> ________ Motor Aphasia.

When Both areas are affected but Arcuate Fasciculus is NOT affected –> ________ Mixed Aphasia.

What presentation will be true for all of these?

Answer 10

Transcortical Sensory

Transcortical Motor

Transcortical Mixed

Repetition will be Intact for all, since Arcuate Fasciculus is intact!

Question 11

What would stroke in the following vessels result in:

ACA

MCA

PCA

Answer 11

ACA –> Transcortical Motor APhasia (Broca affected but NOT Arcuate)

MCA –> Superior MCA = True Broca’s (Arcuate included); Inferior MCA = True Wernicke’s (Arcuate included); Somewhere inbetween –> Global Aphasia

PCA –> Transcortical Sensory (Wernicke affected but NOT Arcuate)

Question 12

Agraphia is an impairment in writing. This can occur WITHOUT ______.

If the patient cannot write with either hand –> lesion in the Dominant (Left) inferior _____ lobe.

If the patient can’t write with the LEFT hand –> lesion in the ______ ______ (can’t coordinate language from Left side of brain with motor functon from Right side of brain).

Answer 12

Aphasia

Left Inferior Parietal Lobe

Corpus Collosum

Question 13

How could Alexia occur WITHOUT Agraphia?

Answer 13

With a LEFT PCA infarct –> the Left Occipital lobe AND Left aspect of the posterior Corpus Collosum will be affected –> The right Occipital lobe wil process info coming in, but it will not be able to cross the Corpus Collosum to communicate with Wernicke’s area on the Left.

Essentially, a L-PCA infarct breaks communication between the Occipital lobe (visual cortex) and Wernicke’s area.

Question 14

Gerstmann’s syndrome results from a lesion in the Left Inferior Parietal lobe (cuts communication between Occipital and Wernicke’s). Look for a tetrad of symptoms including:

1. _____
2. _____
3. _____
4. _____

Answer 14

1. Agraphia
2. Acalculia
3. Right-left disorientation
4. Finger agnosia

Question 15

Both Ideomotor and Ideational Apraxia result from Left Hemisphere Lesions.

How do they present differently?

Answer 15

Ideomotor –> can’t perfor the motor activity (often substitute their body for an item they were asked to demonstrate using - like fingers for scissors).

Ideational –> summational (can’t put a bunch of movememnts together but CAN perform individual motor demonstrations).

Question 16

Verbal Apraxia (aka Aphemia) results from a lesion near ______ area, so Left Inferior _____ gyrus. This is also called Foreign accent syndrome, bc people have trouble making the proper sounds for words.

Answer 16

Broca’s area

Left Inferior Frontal Gyrus

Question 17

Balint’s Syndrome results from a Bilateral ______ ______ watershed infarcts that cause damage bilaterally to the Dorsolateral Parietal-occipital areas. Patient’s present with a tetrad of symptoms including:

1. Occulumotor apraxia (can’t voluntarily control gaze)
2. Optic ataxia (inability to move hand to a visualized object)
3. Simultagnosia (inabliity to recognize two objects at same time)
4. Problems with Depth Perception

Answer 17

Bilateral MCA-PCA Watershed infarcts

Question 18

Patients with Neglect may express _______, which describes associating sensory input from one side of space with the other (e.g. touch patient’s left shoulder, and they say you touched the right).

Answer 18

Allesthesia

Question 19

_______ is similar to Allesthesia, but refers to motor function (e.g. patient is asked to move left arm but moves the right).

Answer 19

Allokinesia

Question 20

Spatial ______ is when a patient is unable to move a body part when it is on the neglected side (e.g. patient with Left neglect can’t move right arm when it’s on the left).

Answer 20

Spatial Akinesia

Question 21

Akinetic Mutism destroys ____ lobe function, so patients will appear to be in a vegetative state, but will have normal sleep-wake cycles and such (they just don’t do or respond to anything).

Answer 21

Frontal lobe

Question 22

Illusions differ from Hallucinations in that Illusions are distortions of what is real, while Hallucinations are perceptions of things that are not there at all.

Which brain areas are these associated with?

Answer 22

Illusions –> primary visual cortex

Hallucinations –> Inferior Temporal-occipital visaul association cortex.

Question 23

Anton’s syndrome is when a patient has complete cortical blindness but does not recognize they can’t see. Their pupils are reactive (should make sense since it’s cortical blindness). This results from Bilateral ______ infarcrts damaging the Primary Visual Cortices bilaterally.

Answer 23

Bilateral PCA infarcts

Question 24

Prosapognosia occurs from damage Bilaterally to the _______-______ cortices (Fusiform gyrus)

Answer 24

Bilateral Occipitotemporal cortices

Question 25

______ ______ syndrome results from a lesion anywhere along the optic tract (from optic nerve to Occipital lobe). Patients have hallucinations of Lilliput (lilliputian - small size) objects in the lost visual field.

Answer 25

Charles Bonnet Syndrome