NSC Exam 4 Study Questions with Complete Solutions 2024/2025 What connects the two hemispheres of the brain? - Correct Answer cerebral commissures What is the procedure that separated the two brain hemispheres? - Correct Answer commissurotomy Aphasia - Correct Answer brain damage-induced deficit in the ability to produce or comprehend language What did Broca discover in his research? - Correct Answer He discovered that all the aphasic patients that he saw had damage to their inferior prefrontal cortex. This became known as "Broca's Area" What is apraxia? What causes it? - Correct Answer the inability to perform certain movements when requested our of context (even though they may be physically able to perform them Almost always caused by left-hemisphere damage What is the theory of cerebral dominance? What thinking did it lead to? - Correct Answer One hemisphere (usually the left) assumes a dominant role in controlling complex cognitive and motor functions This was supported by the fact that aphasia and apraxia are both caused by damage to the left hemisphere It led to people referring to the left hemisphere as the "dominant hemisphere" and the right as the "minor hemisphere" What are three tests used to assess the lateralization of the brain besides lesioning the brain? - Correct Answer 1) sodium amytal test 2) the dichotic listening test 3) functional brain imaging 1 / 4
sodium amytal test - Correct Answer injection is given through the carotid artery which anesthetizes that hemisphere of the brain, allowing the function of the other side to be assessed Neurosurgeons will use it to see which side of the brain is responsible to language dichotic listening test - Correct Answer three pairs of spoken digits are played into both ears simultaneously (e.g. 1,3,6 in the right and 2,4,8 in the left) They have found that people report hearing more of the digits played in their right ear What is the difference between dextrals and sinestrals with brain lateralization? How do we know? - Correct Answer Dextrals almost always have language lateralized to the left, and sinestrals usually do, but it is more variable We have conformed this from Na amytal tests Are males' brains more lateralized than females? - Correct Answer The evidence is mixed. Males have been seen to suffer more consequences from unilateral strokes, but functional brain imaging has not been able to show increased lateralization What is the largest cerebral commissure? - Correct Answer corpus callosum What 3 things did Meyers and Sperry do to restrict visual info to only one eye? - Correct Answer 1) they cut the corpus callosum
- this prevents the hemispheres from communicating
- this prevents signals from the nasal hemiretina from crossing over
- this blocked both visual fields in that eye 2 / 4
2) the cut the optic chiasm
3) they blindfolded one eye
What did Meyers and Sperry find was produced in cats when the optic chiasm was cut? - Correct Answer scotoma (an area of blindness) What did Meyers and Sperry find in they experiment with cats? What was their conclusion? - Correct Answer They found that, in the control group, the cats were unaffected when the eye patch was switched to the other eye. However, the cats went back to zero if their optic chiasm and corpus callosum has been severed They concluded from this that they corpus callosum transfers info between the two hemispheres.What is a common treatment for severe seizures? - Correct Answer commissurotomy of the corpus callosum If an apple was shown in the left visual field of a split brain patient, how could they identify it? How could they not identify it? - Correct Answer The patient would be unable to verbally identify the apple because the right hemisphere is not involved in speech. Therefore, they would say that they didn't see anything.However, they could reach under the table and identify a matching object with their left hand, because it is also controlled by the right hemisphere What is cross-cuing? Give an example - Correct Answer Cross-cuing is where the two brain hemispheres can communicate indirectly through an external route.Ex) if a split brain patient is shown either red, or green in their left visual field, they perform no better than chance at guessing the color. However, if they pick the wrong color, their right hemisphere initiates a frown or some other negative response because it knows the verbal response was incorrect, which prompts the left hemisphere to change its response What is the helping-hand phenomenon - Correct Answer In some experiments, split-brain patients are shown two different things in each visual field and told to grab the object that was shown. The patient tries to grab what was seen by the left hemisphere with the right hand, the right hemisphere sees it and thinks a mistake is being made, so the left hand reaches out and tries to stop the other hand. 3 / 4
What is the chimeric figures test? - Correct Answer Split brain patients are shown a picture of two different peoples' faces combined to make one face. The patient is then asked to describe what they see, and they claim to see a normal, complete face based on the half from the right visual field (left hemisphere). Basically, both hemispheres see normal, complete pictures of faces, rather than the combination What is a Z lens? How is it used? - Correct Answer A Z lens is a contact lens that is opaque on one half, so split brain patients can look at visual stimuli for longer than 0.1 seconds and not have signals go into the other visual field.The Z lens can be used to allow patients to assess complex visual stimuli like text, or even auditory stimuli. The latter works because a patient may hear an auditory command like "pick up the green ball" but then they are only able to see the different colors with one visual field due to the Z lens Can the hemispheres of split-brain patients ever communicate? Give evidence for or against - Correct Answer Yes. Patients who are shown an emotional image in their left visual field (right hemisphere) can often verbally respond with the correct emotional response when asked.What is the most lateralized of all brain functions? - Correct Answer Language Language sounds, speech, reading, writing, and verbal memory are all primarily lateralized to the ______ hemisphere - Correct Answer Left hemisphere Facial recognition, geometry, recognizing geometric patterns, and mental rotations of shapes are all primarily lateralized to the _____ hemisphere - Correct Answer Right hemisphere Recognizing emotional facial expressions and expressing emotional content is primarily lateralized to the _____ hemisphere - Correct Answer Right Words, letters, and arithmetic are lateralized to the ______ hemisphere - Correct Answer Left Which hemisphere plays a greater role in ipsilateral movements? - Correct Answer The left hemisphere
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