Post

Split-brain

The very physical manner in which certain regions of the brain dominate certain functions is completely new to me. One especially interesting example from my enlightening Introductory Psychology course is about the “split-brain” theory.

A split-brain results from the severing of the corpus callosum – a connection between the two hemispheres of the cerebral cortex – in response to severe seizures or injury.

Each hemisphere of the brain controls the muscles on the opposing side of the body along with other specialized functions. Generally, the left-hemisphere is specialized for language and the right-hemisphere for complex visuospatial tasks. For those with an intact corpus callosum, it would be simple to talk about something that was felt in the left hand because the information would easily pass across the large pathway onto the other hemisphere.

However, those with a severed corpus callosum would be feel something with their left hand, but would not be able to describe it because the information would be “trapped” in the right hemisphere (remember that each hemisphere controls the opposite side of the body) which does not focus on speech or language. However, the person would be able to point at the object correctly only with their left hand (Kalat).

Similarly, if a word is flashed quickly on a screen in front of a split-brain patient, they would be forced to interpret what they saw while the information was still separated because they would not have the time to move their eye across the word and establish the information in both hemispheres. If the word flashed is a combination of two words such as “hatband”, the split-brain patient would report only what the left hemisphere saw and would write the word “band” with their right hand. Likewise, their left hand would point to a hat because that is what the right hemisphere saw (Ibid).

It is a somewhat difficult concept to understand because we usually do not think of the physical movement of information within our brains. We really are amazing little creatures.


(Image from www.wwnorton.com)

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At
01:30:00 PM
On
February 24
In
By
Tom Fadial

Comments

  1. I took a Psychology course last year that was truly my favorite class I have ever taken. The teacher was great, and the material we covered was amazing- It’s fascinating how our body and mind work, even though some of what we ‘know’ is theoretical. I really wish that psychology was a general requirement like English, it’s just incredible stuff.

    Kyle Jones

    Feb 26, 11:26 AM #

  2. Yeah, I’m loving the course and am in the process of applying for a research grant that is related to psychology & perception…

    Thame

    Feb 26, 02:25 PM #

  3. That is fascinating. I had never thought about the brain functioning like that.

    Richard

    Feb 27, 04:01 AM #

  4. I know! Isn’t it amazing?

    Enough to make me seriously consider psychology as a major…

    Thame

    Feb 27, 10:45 AM #

  5. I’m in the same boat as you. I’m in the process of completing my Psych 101 course, and i’ve just decided recently to take the plunge and major in Psych.

    Behavioural Neuroscience is what i’m aiming for in the end since i’m primarily interested in the biological.

    There’s lots of this kind of stuff: ever hear of alien hand syndrome?

    Eric. I

    Mar 2, 10:08 PM #

  6. Good luck Eric. If I were to switch to psychology (and I’m definitely considering it), I would probably focus on something similar because I’m pretty sure that I want to study biology too.

    For those who are interested, the Wikipedia entry for the Alien Hand Syndrome can be found here.

    Thame

    Mar 3, 03:57 AM #

  7. Thame,

    I recently graduated from BU, where I majored in Psychology. It’s a great subject, one that I’m still very passionate about, particularly in the areas of cogniton and perception. I could talk your ear off if you really, really wanted.

    re: split-brain patients. I believe it was found that after a long period of time, the two halves of the patient’s brain would differentiate, to a certain extent. In a couple of cases the “mute” hemisphere even picked up some rudimentary language.

    Jonathan Dobres

    Mar 4, 09:45 PM #

  8. That sounds great, we should have a little talk then. My contact information is listed here.

    I’m really getting excited (psyched) about psychology too and am in the process of applying for a research grant for a psychology-related project I’m going to do. I can’t wait.

    About the split-brains and the language acquisition of the mute hemisphere, is that a result of some kind of a new connection that is reconstructed or is it a learning process with the hemispheres still split?

    Thame

    Mar 4, 10:10 PM #

  9. Reconnection of the corpus collosum is, as far as I know, impossible. Some evidence suggests that the split hemispheres “learn” some of their missing functions, though “learn” isn’t exactly the right word.

    Jonathan Dobres

    Mar 4, 11:21 PM #

  10. That’s really interesting, I’ll have to look into it.
    Any review articles you would suggest?

    Thame

    Mar 5, 06:55 AM #

  11. None that I can remember off the top of my head, though I think Sperry and Gazzaniga did a lot of research into it.

    Jonathan Dobres

    Mar 5, 07:17 AM #

  12. Thanks, I’ll take a look.

    Thame

    Mar 5, 04:41 PM #

  13. It would make a good deal of sense that the hemispheres have built in plasticity to some extent, and therefore they regain their lost information (and yes, the corpus collosum split is not able to grow back to the best of my knowledge).

    I say this because children that have an entire cerebral hemisphere removed early on regain much, nearly all, of the functions a full brain would have. So if the right hemisphere were to be removed they would still learn how to recognize faces and spatial information.

    In adults it’s a little trickier since the brain does not recover nearly as nicely, but the brain reacts to the information it recieves and therefore it makes some sense that each hemisphere regains some lost information.

    Eric. I

    Mar 5, 05:16 PM #

  14. I figured that the callosum would not be able to grow back, but perhaps the brain could find another linking route.

    I have also read some pretty amazing case studies concerning what you described with children. This is definitely something I’ll be looking into.

    Thame

    Mar 6, 06:34 AM #

  15. Hey, I thought i’d point out this to you: http://www.fordham.edu/halsall/ancient/suetonius-julius.html

    Now, that’s interesting!

    Eric. I

    Mar 16, 01:45 PM #

  16. OOPS, wrong link. That would be for a caesar project i’m working on.

    http://scienceblogs.com/.../_see_col.php

    There we go.

    Eric. I

    Mar 16, 01:47 PM #

  17. Cool, thanks. I shortened up your link text, hope you don’t mind.

    Thame

    Mar 17, 10:25 AM #

  18. Mi hai schiacciato forte abbastanza
    da vedere cosa ne esce. Una passione esonde.
    Pericolosa come un fuoco senza cerchio.
    Provai a domarla implodendomi i sensi.

    PER CLAUDIA

    May 30, 11:01 AM #

  19. hello im working a case study for some patient who undergo in split brain

    essa

    Jul 1, 03:47 AM #

  20. essa:
    Wow, that’s incredible! Have you learned anything interesting that I haven’t covered?

    Thame

    Jul 1, 07:51 PM #

  21. hello, i’m looking for the answer of this question; what do split brain studies tell us about language?
    this is my question. i forward to ur replying as soon as possible.
    thank you

    muneer

    Apr 30, 01:29 AM #

  22. dear sir
    could u answer the following question for me.
    is language the product of learning (nature,innate ) or nurture

    rashad

    May 5, 10:34 AM #

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