KEY CONCEPTS
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Split Brains: A House Divided [p.134]
INTRODUCTION
The hemispheres are in constant communication. This section covers what happens if the communication was cut off by severing the corpus callosum.
KEY CONCEPTS EXPLAINED
Cat Lovers Don't Read this Section!
Split Brain Surgery on Cats
| Severing the corpus callosum and parts of the nerves to the eyes resulted in the
left eye sending information to one isolated hemisphere and the right eye sending
information to the other isolated hemisphere. Tricks the cats learned with their left eye open could not be performed when tested with their right eye open. One side of the brain did not know what the other side was doing! |
Cat Lovers Revenge:
Split Brain Surgery on Humans
| Used a a last resort to control epilepsy. No apparent change in functioning under normal circumstances. Under laboratory conditions, however, strange things did occur. |
- The laboratory setting could control for eye movement and took advantage of the
fact that the left visual field sends information to the right hemisphere and the
right visual field goes to the left hemisphere.
- Photos that were cut and paste combinations of other photos were then presented to the split brain surgery patients.
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Results to the Question: "What do you See?"
Verbal Answer "The boy" Why? Because the language center is in the left hemisphere, and the left hemisphere only saw the Boy
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Results to the Question: "Point with your LEFT hand to what you saw."
Pointed to: "The Man with the mustache" Why? Because the left hand is controlled by the right hemisphere and it guided the hand to the image it had seen, the Man with the mustache
Would you like to review the figure from the text?
GLOSSARY
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corpus callosum |
LINKS About Split Brain Surgery
- weblink: Overview of the split brain procedure.
- weblink: Overview of the effects of the split brain operation.
- weblink: The personal journal of a person who had the operation.
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A Question of Dominance [p.136]
INTRODUCTION
Does the left hemisphere dominate the right hemisphere?
KEY CONCEPTS EXPLAINED
The left hemisphere got its title as dominant because:
- Usually contains the language center.
- More active in logical, symbolic, and sequential tasks (rational and analytic
mode) -- as in math tests.
- May contain a mental "module" that tries to explain actions/emotions of nonverbal or nonconscious brain parts.
In defense of the right hemisphere:
- Superior in spatial-visual ability, facial recognition, and ability to read facial
expressions.
- Artistic and musical creativity and appreciation.
- Cognitive style that might be more intuitive and holistic.
Popular Misconception: "Right Brain, Left
Brain Learning Programs?"
The difference between the hemispheres are a matter of degree (not absolute) and they work cooperatively with each other to produce our behavior.
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| Next Topic - Two Stubborn Issues in Brain Research.....................Chapter Contents |