Anat: Higher Cerebral Function

Question 1

What is a focal brain lesion?

Answer 1

Lesion to an area of the cerebral cortex with only one function.

Question 2

What is the most obvious asymmetry in cerebral function?

Answer 2

Handedness
(left hemisphere is dominant for language in the majority of the population because most are right handed with a left dominant cerebral hemisphere)

Question 3

What are the Peri-Sylvian connections?

Answer 3

Located in the arcuate fasiculus. Fibers that integrate the Broca’s and Wernicke’s areas. Allows us to interpret language and produce language at the same time such as reading out loud.

Question 4

In most people the left side is dominant and is important for language comprehension and formation. Why is integrating signals to the right side of the brain in the areas analogous to Broca’s and Wernicke’s areas important in language.

Answer 4

The right side (in most people) is important for interpreting emotion of language and comprehending tone and expression of language that is heard.

Question 5

What is aphasia?

Answer 5

Defect in language processing due to lesions in the dominant brain hemisphere.

Question 6

Describe Broca’s Aphasia.

Answer 6

• inability to speak
• decreased fluency
• short sentence length
• naming difficulties
• writing and reading aloud is impaired
• usually caused by superior division MCA infarct.

Question 7

Describe Wernicke’s Aphasia.

Answer 7

• inability to comprehend language
• can speak but words are meaningless
• semantic errors (might say ink when they mean pen)
• MCA inferior division infarct

Question 8

Common visual symptom associated with Wernicke’s Aphasia.

Answer 8

Pie in the Sky lesion

-wernicke’s has the same blood supply as meyer’s loop

Question 9

Why is Wernicke’s Aphasia often misdiagnosed?

Answer 9

Patients often become frustrated with an inability to comprehend any kind of language and they become angry. They are often diagnosed and send to psychiatric facilities.

Question 10

What type of lesion leads to a mixed transcortical aphasia?

Answer 10

MCA and ACA watershed infarct
and
MCA and PCA watershed infarct

Question 11

What type of lesion leads to a transcortical motor aphasia?

Answer 11

MCA and ACA watershed infarct

Question 12

What type of lesion leads to a transcortical sensory aphasia?

Answer 12

MCA and PCA watershed infarct

Question 13

What type of lesion leads to a conduction aphasia?

Answer 13

Peri-sylvian lesion

Question 14

Define:

1. Alexia
2. Agraphia
3. Apraxia

Answer 14

1. Inability to read
2. Inability to write
3. Inability to carry out an action or understand tasks even when full motor capability is intact

Question 15

What is Aphemia?

Answer 15

Verbral apraxia. Foreign accent syndrome. Patients are unable to articulate speech muscles.

Question 16

What causes alexia without agraphia?

Answer 16

Infarct in the PCA that creates a lesion in the dominant side visual cortex AND posterior portion of the corpus callosum.

Patients cannot send visual data to Wernicke’s area for interpretation because of the damaged visual cortex on the same side of Wernicke’s and corpus callosum and they also have opposite side hemanopsia.

(if the non-dominant side was damaged, reading would still be intact)

Question 17

Describe Gerstmann’s Syndrome.

Answer 17

Lesion in the inferior pole of the parietal lobe.
Patients present with:
-agraphia
-acalculia (can't do math)
-right/left disorientation
-finger agnosia

Question 18

Patients can hear sounds with cortical deafness, pure word deafness, and non-verbal auditory agnosia. What are the differences between these 3?

Answer 18

1. Cortical Deafness: bilateral primary auditory cortex lesion
   - can’t interpret language or non-verbal sounds

Pure Word Deafness: dominant auditory cortex infarct

• can understand non-verbal sounds but not language
• can read, write, and speak

Non-verbal Auditory Agnosia: non-dominant auditory cortex infarct
-can understand language but not non-verbal sounds

Question 19

Why do non-dominant hemisphere strokes lead to contralateral neglect?

Answer 19

The dominant hemisphere pays attention only to the contralateral “world”. The non-dominant side pays attention to both sides of the “world”. Damage to the non-dominant side often leads to neglect of the opposite side “world”.

Question 20

What are allesthesia and allokinesia?

Answer 20

Both are releated to contralateral neglect.
Allesthesia: touching a patient on the neglected side stimulates sensation on the opposite side (in their mind).
Allokinesia: asking a patient to move the neglected side body and they move the opposite side.

Question 21

What is anosognosia?

Answer 21

Patients with contralateral neglect have no awareness of the illness.

Question 22

What is anosodiaphoria?

Answer 22

Patients with contralateral neglect know that they have the illness but do not care or show concern.

Question 23

What is hemiasomatognosia?

Answer 23

Patients deny that the neglected side of their body belongs to them.

Question 24

Describe Anton’s Syndrome or Cortical Blindness.

Answer 24

Bilateral lesion of the visual cortex. Patients are visually blind but they don’t know that they are blind (anosognosia).

Question 25

Describe Blindsight.

Answer 25

Phenomenon where patients are visually blind but they can still track objects in motion. Some research has even documented patients able to put envelopes in mail slots without being able to see.

Question 26

What is prosopagnosia?

Answer 26

Inability to recognize faces.

Question 27

What is palinopsia?

Answer 27

Memories of past visual information are projected into the visual field of patients when the objects are not really in the visual field.

Question 28

What is erythropsia?

Answer 28

Viewing unnatural colors.

Question 29

Describe Balint’s Syndrome.

Answer 29

Infarct at MCA/PCA region causing bilateral lesion of the dorsolateral-parietoccipital cortex.
Patients present with Simultagnosia (can’t see parts of objects as a whole), optic ataxia, optic apraxia.

Question 30

Region of the brain that is involved with directing attention.

Answer 30

Frontal/Parietal associations cortex

Question 31

Region fo the brain that is invovled in motivation.

Answer 31

Anterior Cingulate Gyrus/Limbic Cortex

Question 32

Region of the brain involved in visual tracking.

Answer 32

Tectum, pre-tectal area, pulvinar, frontal eye field