Stare at a Dot as He Flashed He Art on a Screen

ii.2 The story of the split brain patients

A surgical procedure that cuts through the corpus callosum has provided evidence to support the different specialisations of the left and right hemispheres of the encephalon. This procedure is used very rarely and always as a final resort when someone has frequent and major epileptic seizures that do not reply to drug handling. The frequency and severity of their epileptic fits is very disabling and their quality of life is poor. The attacks can even exist life threatening. In these patients epileptic activity would kickoff in ane area of the brain and then spread beyond the corpus callosum to all areas of the brain. By cutting these connections between the two hemispheres epileptic activity is independent in i hemisphere but. The operation usually leads to a significant subtract in the frequency and severity of the seizures without any apparent interference in normal functioning.

Early researchers were puzzled by the fact that people who had undergone this performance did not testify any noticeable changes in behaviour, personality or their scores on intelligence tests despite such extensive surgery. In fact they wondered what the purpose of the corpus callosum was if you could cutting through it with so piddling effect. However conscientious testing by Roger Sperry (1968) and colleagues did uncover behaviour that was far from normal. This work was to proceeds him a Nobel Prize for Medicine in 1981.

Sperry et al, devised a number of split brain experiments using people who had had split brain surgery every bit participants and comparing their responses to people who had non had this surgery. In one experiment the divide brain participant was blindfolded and given objects to explore with their left mitt. Information from the left paw goes to the right hemisphere simply spoken language is generally controlled by the left hemisphere.

Participants were unable to tell the experimenter the name of the object they were belongings in their left hand fifty-fifty though they could obviously recognise the object because they would make appropriate gestures with it. For case, if the object was a key they would hold it out as though putting it in a lock and turn it. Because the right hemisphere does non talk and could not transfer information to the left hemisphere the object cannot be named. However every bit soon as the participant touched the object with the right hand they were able to name information technology instantly.

In another experiment the participant would sit at a table with a screen in front of them. They would be asked to place their easily round the sides of the screen then that their hands were hidden from view. They would then be asked to set their eyes on a spot in the centre of the screen.

Figure 3 A split brain study

A word is then flashed onto one side of the screen very briefly (approximately one tenth of a second). The word has to exist flashed very quickly so that the participant does not accept fourth dimension to motility their eyes and the data volition but go to 1 of the brain hemispheres.

When a give-and-take is flashed on to the left-hand side of the screen the information volition become to the correct hemisphere of the brain. The information cannot exist passed to the talkative left hemisphere so the participant cannot tell the experimenter what the give-and-take was.

However the participant can employ their left hand to explore a pile of objects behind the screen and hands pick out the object that corresponds to the give-and-take that has been flashed upwards. They still won't be able to tell the experimenter what the left hand is doing as sensory data from the left hand is going to the silent correct hemisphere only. Also they can't find the right object with their correct mitt as the right paw is controlled by the left hemisphere and the left hemisphere did not run across the flashed word.

Activity ii: Sorting out right from left

Timing: 0 hours 10 minutes

Reading most split up encephalon experiments can be a fiddling disruptive every bit you effort and sort out right and left hands, hemispheres and sides of the screen. Taking some time to do this activeness should help to make things clearer.

1 If a give-and-take is flashed on the correct mitt of the screen will a person with a carve up brain be able to:

	Yeah	No
(a) name the word	To use this interactive functionality a free OU account is required. Sign in or register.	To apply this interactive functionality a free OU account is required. Sign in or register.
(b) pick out the respective object from backside the screen with their right hand	To use this interactive functionality a free OU account is required. Sign in or annals.	To use this interactive functionality a free OU account is required. Sign in or register.
(c) pick out the respective object from behind the screen with their left paw	To utilise this interactive functionality a free OU account is required. Sign in or register.	To use this interactive functionality a free OU account is required. Sign in or register.

Interactive characteristic non available in unmarried page view (see information technology in standard view).

Discussion

Don't worry if you constitute this activity difficult. Many people find following a path from a word on the right side of the screen to the left hemisphere of the brain and then to the right hand far from easy.

In question 1 the word was flashed on the right side of the screen so the information will go to the left hemisphere of the brain. As speech is ordinarily controlled by the left hemisphere the person should be able to proper name the word. As the left hemisphere besides controls the right side of the trunk the person will be able to pick out a hidden corresponding with their right hand but not with their left hand.

So the answers to question i are

• (a) yep

• (b) yes

• (c) no

Activeness 2b

ii If a word is flashed on the left hand of the screen will a person with a split up brain exist able to:

	Yes	No
(a) name the word	To use this interactive functionality a free OU account is required. Sign in or annals.	To use this interactive functionality a free OU business relationship is required. Sign in or register.
(b) pick out the corresponding object from behind the screen with their right hand	To use this interactive functionality a free OU business relationship is required. Sign in or register.	To apply this interactive functionality a free OU account is required. Sign in or register.
(c) pick out the corresponding object from backside the screen with their left manus	To apply this interactive functionality a costless OU account is required. Sign in or register.	To use this interactive functionality a free OU account is required. Sign in or register.

Interactive feature not available in unmarried page view (come across it in standard view).

Answer

The word is flashed to the left side of the screen so the information will get to the right hemisphere. The person will not be able to proper noun the word and volition not be able to pick out a corresponding hidden object with their right hand. This is considering the right hemisphere does not control speech or the correct side of the body. The right hemisphere controls the left side of the body so the left hand will exist able to select a corresponding object.

Then the answers to question 2 are the opposite to those for question i:

• (a) no

• (b) no

• (c) yes

In split brain experiments the techniques used will limit information to i hemisphere only and the person behaves as if they have two separate brains with each hemisphere appearing to operate with no conscious awareness of what is happening in the other hemisphere.

Of course in everyday activities split brain people can operate normally because they can move their optics and make sure that incoming information is available to both hemispheres. Occasionally odd behaviours do occur, especially in the early days later on surgery. A patient might detect that they are buttoning up a shirt with one manus and unbuttoning information technology with the other paw or that their left mitt suddenly closes a book that they were engrossed in.

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Source: https://www.open.edu/openlearn/health-sports-psychology/psychology/starting-psychology/content-section-2.2

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