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The frontal lobes in your brain are vital for many important functions. This include voluntary movement, speech, attention, reasoning, problem solving,. Health Conditions Discover Plan Connect. Left Brain vs. Medically reviewed by Deborah Weatherspoon, Ph. How the human brain works The human brain is an intricate organ. Share on Pinterest. Tips for keeping your brain sharp.
Tips for boosting creativity. The bottom line. Read this next. What Is a Choroid Plexus Cyst? Medically reviewed by Mia Armstrong, MD. This type of surgery is performed in patients suffering from epilepsy. The corpus callosum is cut to prevent the spread of the "epileptic seizure" from one hemisphere to the other.
Roger Sperry who won the Nobel prize in and Michael Gazzaniga are two neuroscientists who studied patients who had surgery to cut the corpus callosum. These studies are called "Split-Brain Experiments". After surgery, these people appeared quite "normal" - they could walk, read, talk, play sports and do all the everyday things they did before surgery.
Only after careful experiments that isolated information from reaching one hemisphere, could the real effects of the surgery be determined.
Sperry used a tachistoscope to present visual information to one hemisphere or the other. The tachistoscope requires people to focus on a point in the center of their visual field. Because each half of the visual field projects to the opposite site of the brain crossing in the optic chiasm , it is possible to project a picture to either the right hemisphere OR the left hemisphere.
So, say a "typical" language in the LEFT hemisphere split-brain patient is sitting down, looking straight ahead and is focusing on a dot in the middle of a screen.
Then a picture of a spoon is flashed to the right of the dot. When the person is asked what the picture was, the person has no problem identifying the spoon and says "Spoon. Now if the person is asked what the picture was, the person will say that nothing was seen!!
But, when this same person is asked to pick out an object using only the LEFT hand, this person will correctly pick out the spoon. This is because touch information from the left hand crosses over to the right hemisphere - the side that "saw" the spoon. However, if the person is again asked what the object is, even when it is in the person's hand, the person will NOT be able to say what it is because the right hemisphere cannot "talk.
Another type of experiment performed with split brain patients uses chimeric figures , like this one to the right. In this figure, the face on the left is a woman and the face on the right is a man. Therefore, if the patient focuses on the dot in the middle of the forehead, the visual information about the woman's face will go to the right cerebral hemisphere and information about the man's face will go to the left hemisphere.
When a split brain patient is asked to point to a whole, normal picture of the face that was just seen, the patient will usually pick out the woman's picture remember, the information about the woman's face went to the RIGHT cerebral hemisphere. However, if the patient is required to say whether the picture was a man or a woman, the patient will SAY that the picture was of a man.
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