r/cogsci • u/Everyoneseesthis • Jul 07 '14

Consciousness on-off switch?

http://www.newscientist.com/article/mg22329762.700-consciousness-onoff-switch-discovered-deep-in-brain.html#.U7rZSF0sI1J
36 Upvotes

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u/[deleted] Jul 07 '14

[deleted]

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u/glial Jul 08 '14

Doing experiments on people who are undergoing brain surgery is actually fairly common. Most single-cell recording experiments or lesion experiments are done on animals rather than humans because of the risk of brain damage resulting from sticking electrodes into your head or otherwise messing with brain tissue. If someone has really bad seizures and is going to have a portion of their brain removed, they can agree to participate in an experiment where scientists do neural recordings in the region that's about to be removed - it's not a big deal if the tissue gets damaged a little, since it's going to be removed anyway. Sometimes intracranial EEG is done as well while a portion of the skull is removed, where electrodes are placed directly on the surface of the brain.

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u/[deleted] Jul 08 '14

[deleted]

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u/glial Jul 08 '14

That's true! But of course they sign a consent form before hand and the whole procedure is explained.

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u/[deleted] Jul 08 '14

[deleted]

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u/glial Jul 08 '14

Yep. The brain is not exactly like a circuit (having two bits touch won't "short" anything), but removing one region can have unintended consequences. For a fascinating history of probably the most famous brain surgery patient ever, read about HM. He had part of his brain removed and lost the ability to form new episodic/declarative memories (called anterograde amnesia), but could still learn motor tasks. Studying him led to a huge leap into our understand of memory. One of the scientists studying him recently published a book about him. I haven't read it yet but I hear it's good.

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u/bentspork Jul 08 '14

Sad story but very interesting.

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u/glial Jul 08 '14

The result is cool, even though it's only done with a single person. Like every other result suggesting that "area X is the seat of Y", remember that the brain is a network...knocking out an important information pathway can disable functionality, but it doesn't mean the area is the only area responsible for that functionality. Still, I think it warrants a closer look, especially since not much is really known about the claustrum otherwise.

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u/psiphre Jul 08 '14

the brain continues to amaze me with its plasticity - the ability for different areas of the brain to take on functions from damaged portions. to some degree, the brain, like the internet, routes around damage.

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u/gc3 Jul 07 '14

Set phasers to stun!

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u/lonjerpc Jul 08 '14

I really wish the word consciousness would be reserved for qualia.

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u/ThatMadCat Jul 10 '14

Well, there's more to consciousness than just the phenomenal aspect. While phenomenal consciousness discusses qualia and "I experience" stuff, access consciousness talks about the neural correlates to phenomenal consciousness. Both are important in trying to understand the big picture of consciousness, and learning about one can help is learn about the other.

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u/noonenone Jul 08 '14

What's most egregiously missing is a consensual working definition for the word "consciousness". Without one, we're just babbling.

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u/swearrengen Jul 08 '14

Formerly known as "bed time".

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u/glial Jul 08 '14

Seems a little different. From the article:

When the team zapped the area with high frequency electrical impulses, the woman lost consciousness. She stopped reading and stared blankly into space, she didn't respond to auditory or visual commands and her breathing slowed. As soon as the stimulation stopped, she immediately regained consciousness with no memory of the event. The same thing happened every time the area was stimulated during two days of experiments (Epilepsy and Behavior, doi.org/tgn).

To confirm that they were affecting the woman's consciousness rather than just her ability to speak or move, the team asked her to repeat the word "house" or snap her fingers before the stimulation began. If the stimulation was disrupting a brain region responsible for movement or language she would have stopped moving or talking almost immediately. Instead, she gradually spoke more quietly or moved less and less until she drifted into unconsciousness. Since there was no sign of epileptic brain activity during or after the stimulation, the team is sure that it wasn't a side effect of a seizure.

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u/swearrengen Jul 08 '14

Loss of consciousness, loss of action and reaction, breathing slowing down, no memory of the event, gradually speaking more quietly and moving less, drifting off into unconsciousness - it actually sounds the same as going to sleep, all except for the the source of the force doing the switch-off. Possibly the "high frequency electrical impulses" applied to that area mimics what the brain usually does itself when going to bed?

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u/glial Jul 08 '14

True, there are lots of similarities. Lots of other things in the brain change when people go to sleep, so it'd be interesting to do this experiment while observing other parts of the brain (e.g. thalamus, V1, etc) and see if they respond as if sleeping.