NEUR30004 Study Guide - Final Guide: Skipping Rope, Agenesis, Scientific Reports
5 Oct 2020
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NEUR30004 Sensation, Movement & Complex Functions Split Brain Studies
Student Worksheet 2020-10-05
1
Left Joe, Right Joe
The “skipping rope” mystery is the hardest thing to explain in the video of Vicki. It can be explored further
with another split brainer, Joe. In this video, Joe is tested by simultaneously projecting a different word into
each hemisphere, "bell" into his right hemisphere and "music" into his left. He is asked, "What did you see?"
19. Which word would he say he saw, "bell" (left visual field), or "music" (right visual field)?
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20. What is the significance of the hand Joe uses to point to the matching picture?
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21. What is the significance of the story Joe tells about why he pointed to a picture of bells although other
pictures related more obviously to music? How does this relate to Vicki and the skipping rope mystery?
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If Joe’s right hemisphere is still able to influence the behaviour of the left hemisphere, the ability is very
limited. Watch what he draws when “toad” is flashed to his left visual field and “stool” is shown to his right.
23. What does this video indicate about the language ability of the Joe's right hemisphere?
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Agenesis of the Corpus Callosum
Fortunately, surgically splitting the brain is done only very rarely, but this fact greatly limits the number of
cases that can be studied. All or part of the corpus callosum can be missing in people with the development-
al disorder, agenesis of the corpus callosum (ACC). However, this abnormality generally does not produce
people that show similar outcomes to surgically-made split brainers.
Split Brains: the wrap-up
It would be wrong to conclude that hemispherical specialisation is all or none, that language or some
other neural process is strictly confined to only one side. In reality, while we can find “dominance” by
one side, it is rare that the other side has no capacity or role at all in a particular function.
A further consideration is the differences between individuals with split brains. It is surgically difficult
to cut all of the corpus callosum, sometimes a small part remains intact. In addition, other routes
linking the two hemispheres usually remain. No patient ever really has a completely divided brain, and
each individual is “split” to a different extent. In addition, the people concerned all have severe
epilepsy with possible concomitant changes in brain function.
Finally, textbooks and videos (and scientific reports) always feature the most interesting / extreme
cases, and hardly ever the ambiguous ones.
Document Summary
The skipping rope mystery is the hardest thing to explain in the video of vicki. It can be explored further with another split brainer, joe. In this video, joe is tested by simultaneously projecting a different word into each hemisphere, "bell" into his right hemisphere and "music" into his left. If joe"s right hemisphere is still able to influence the behaviour of the left hemisphere, the ability is very limited. Fortunately, surgically splitting the brain is done only very rarely, but this fact greatly limits the number of cases that can be studied. All or part of the corpus callosum can be missing in people with the development- al disorder, agenesis of the corpus callosum (acc). However, this abnormality generally does not produce people that show similar outcomes to surgically-made split brainers. It would be wrong to conclude that hemispherical specialisation is all or none, that language or some other neural process is strictly confined to only one side.
