Deck 17: Extension: A - Cortical Networks and Disconnection Syndromes

Question 1

Those areas of the monkey neocortex that receive the densest interhemispheric connections are those that:

A) are phylogenetically oldest.
B) are most commonly damaged by trauma, stroke, etc.
C) represent the lateral portions of the body.
D) represent the midline portions of the body.

Answer 1

represent the midline portions of the body.

Question 2

In cases of agenesis of the corpus callosum, which of the following structures would you expect to be larger than normal?

A) the hippocampal commissure
B) the visual cortex (area 17)
C) the anterior commissure
D) fornix

Answer 2

the anterior commissure

Question 3

Similar to the function of the corpus callosum, the anterior commissure connects parts of various brain regions, including all of the following EXCEPT the:

A) amygdala.
B) hippocampus.
C) anterior temporal lobe.
D) paralimbic cortex.

Answer 3

hippocampus.

Question 4

A study by Steele and colleagues used DTI to examine white - matter organization in early - trained versus late - trained musicians. Results indicated which pattern of connectivity?

A) The size of the posterior corpus callosum increased in early-trained musicians.
B) The size of the anterior corpus callosum increased in late-trained musicians.
C) The size of the posterior corpus callosum decreased in early-trained musicians.
D) The size of the anterior and posterior corpus callosum was equivalent in both groups of musicians.

Question 5

In Liepmann's theory of left - hand apraxia, the MOST likely location of the lesion would be:

A) the posterior corpus callosum.
B) the anterior corpus callosum.
C) Broca's area.
D) the anterior commissure.

Question 6

Compared with individuals commissurotomized in adulthood, subjects with agenesis of the corpus callosum:

A) show virtually the same behavioral patterns.
B) have difficulty with interhemispheric transfer of complex stimuli.
C) show no differences from normal, intact subjects.
D) have more right-hemisphere language localization than the general population.

Question 7

The only sensory system whose afferent fibers do NOT cross is:

A) the olfactory system.
B) the auditory system.
C) the somatosensory system.
D) the vestibular system.

Question 8

Damage to the body (middle region) of the corpus callosum would MOST likely impair a subject's ability to:

A) match left and right limb position with eyes closed.
B) use external cues to control impulsive behavior.
C) read aloud words presented selectively to the right hemisphere.
D) name an odor presented to the right nostril.

Question 9

A subject with damage to the anterior commissure would be impaired on a task examining interhemispheric transfer of:

A) visual stimuli.
B) tactile stimuli.
C) vestibular stimuli.
D) olfactory stimuli.

Question 10

If Downer had sectioned all commissures but left the optic chiasm intact:

A) he would have found exactly the same results as if the optic chiasm had also been sectioned.
B) the animal would have appeared wild regardless of which side the stimulus was presented on.
C) the animal would have appeared tame regardless of which side the stimulus was presented on.
D) the animal would have reacted with aggression but not appeared wild.

Question 11

In those individuals who undergo a callosal transection, which of the following is TRUE?

A) Ipsilateral pathways may become stronger in younger patients.
B) Ipsilateral pathways are enhanced regardless of the age at transection.
C) New contralateral pathways are formed in younger patients.
D) New contralateral pathways can be generated at any age.

Question 12

The surgical severing of interhemispheric fiber pathways is called:

A) hemispherectomy.
B) commissurotomy.
C) leukotomy.
D) colostomy.

Question 13

Mishkin and his colleagues have extended the study of cortical disconnection to:

A) animal models using monkeys.
B) human split-brain subjects.
C) animal models using rats and mice.
D) computer simulations of behavior.

Question 14

The term "disconnection syndrome" is used to describe the behavioral effects of:

A) an interruption of communication between two cerebral regions.
B) the destruction of one or more cortical regions contributing to a neural network.
C) the disruption of communication between the brainstem and cerebrum.
D) psychiatric disorders characterized by out-of-body experiences.

Question 15

Analysis of cerebral "hub networks" shows a differential pattern of connectivity among brain regions such that the:

A) posterior cingulate exhibits among the highest level of connectivity.
B) anterior cingulate exhibits among the highest level of connectivity.
C) middle temporal gyrus exhibits among the highest level of connectivity.
D) insular cortex exhibits among the highest level of connectivity.

Question 16

Commissurotomy is performed in humans primarily as a treatment for:

A) schizophrenia.
B) severe migraine headaches.
C) Parkinson's disease.
D) epilepsy.

Question 17

Most projections of the corpus callosum are:

A) organized topographically and project ipsilaterally.
B) diffusely distributed and project contralaterally.
C) organized topographically and project contralaterally.
D) organized homotopically and project subcortically.

Question 18

The MOST posterior portion of the corpus callosum is called the:

A) splenium.
B) genu.
C) uncinate.
D) rostrum.

Question 19

Olfactory information crosses from one hemisphere to the other via the:

A) corpus callosum.
B) olfactory commissure.
C) anterior commissure.
D) hippocampal commissure

Question 20

The single region of the rhesus monkey brain that does NOT have many interhemispheric connections is the:

A) insular cortex.
B) dorsolateral prefrontal cortex.
C) primary visual cortex.
D) Wernicke's area.

Question 21

A patient with a complete transection of the corpus callosum would have particular difficulty proficiently:

A) writing a letter using a pencil or pen.
B) using a canoe paddle.
C) using a gaming console.
D) pouring coffee into a cup.

Question 22

Damage to the splenium of the corpus callosum would MOST probably result in:

A) loss of bimanual coordination.
B) nonfluent aphasia.
C) visual agnosia.
D) acopia.

Question 23

The 1965 monograph, "Disconnexion Syndromes in Animals and Man," reintroduces a concept introduced many years before by:

A) Geschwind.
B) Sperry and Gazzaniga.
C) Kimura and Hampson.
D) Dejerine and Liepmann.

Question 24

According to Geschwind's disconnection theory, bilateral apraxia occurs when there is a disconnection of:

A) auditory and speech areas in the left hemisphere.
B) motor and speech areas in the left hemisphere.
C) motor and auditory areas in the right hemisphere.
D) motor and speech areas in the right hemisphere.

Question 25

Functionally, the visual system is entirely crossed, such that stimuli in the left - visual field are initially processed by the right - visual cortical areas and vice versa. Which of the following systems is MOST similar to vision in this regard?

A) audition
B) somatosensory
C) olfaction
D) taste

Question 26

If a familiar object were placed out of sight in the left hand of a commissurotomy patient, that person:

A) would fail to recognize the object.
B) could identify it verbally, if prompted.
C) could point to a matching object only with his or her right hand.
D) could point to a matching object only with his or her left hand.

Question 27

On which of the following tasks would you expect to see the LEAST impairment following hemispheric disconnection?

A) puzzle assembly
B) dichotic listening
C) tactile apperception
D) chimeric face perception

Question 28

Imaging studies of subject M.C. have shown that, following callosotomy, there is _____ to the site of sensory stimulation.

A) increased neural activity ipsilateral
B) increased neural activity contralateral
C) decreased neural activity ipsilateral
D) decreased neural activity contralateral

Question 29

Impairments in bimanual coordination following hemispheric disconnection appeared to be reduced when subjects performed actions that required:

A) a high degree of conscious control.
B) a minimal degree of conscious control.
C) manipulation of household objects.
D) new stimulus-response learning.

Question 30

Hub disconnection provides a possible explanation for severe chronic deficits exhibited by which patient population?

A) contralateral neglect
B) Huntington's disease
C) epilepsy
D) traumatic brain injury

Question 31

Visual agnosia and alexia are each probably due to damage to white matter in the _____ hemisphere.

A) anterior left
B) posterior left
C) anterior right
D) posterior right

Question 32

The lesion MOST associated with hemispatial neglect is the:

A) gray matter of the right posterior parietal cortex.
B) gray matter of the left posterior parietal cortex.
C) white matter of the right posterior parietal cortex
D) white matter of the left posterior parietal cortex.