7 Fascinating Brain Disorders

I’ve come across some very interesting brain disorders as part of my uni reading (as well from blogs etc). Just as examples of poor design form the best evidence for evolution, so too do the brain’s imperfections tell us more than a “normal” brain. Here’s a list of the disorders I found most bizare and interesting. All dialogue is for illustrative purposes and was made up by me in its entirety.

1. Pain Asymbolia:
   Doctor: Are you experiencing any aches or pains?
   Patient: Yes, there’s an extremely strong pain in my leg — the strongest I’ve ever felt in my life.
   Doctor: Would you like some pain-killers then?
   Patient: No. I feel the pain, but it doesn’t bother me.
   It seems the notion that you have a pain and the distress that accompanies the pain are not identical, and you can keep the first whilst losing the latter. Maybe it’s a bit like having a throbbing pain while you’re asleep, where it just registers but doesn’t actually bother you? (Of course for most people once the pain becomes strong enough it probably spills into distress even if they’re asleep.)
2. Split brain patients:
   Doctor (showing the patient a bottle so that it’s only visible to their left-side vision): Have a good look at this object. (Takes away bottle.) Now tell me what you saw.
   Patient: I didn’t see anything. You never showed me an object.
   Doctor (moments later, taking out a ball, a bottle and a phone): Can you please choose an object out of these three?
   Patient silently points to the bottle.
   Doctor: Why did you choose the bottle?
   Patient: Because I haven’t had any water for so long. Would it be ok for me to have a drink?
   It’s a bit of an urban myth that the left brain is logical/mathematical and the right brain is creative: reality’s more complicated than that. But the left brain is the one that is most associated with language namely producing speech. Some sufferers of epilepsy have had their corpus callosum severed to restrict siezures to one hemisphere only. The result is 2 completely independent hemispheres, and you might even say 2 persons sharing the same body. In an extreme situation, a patient’s left hand was putting on pants while the right hand was trying to stop it because the relevant hemisphere thought that was a bad idea.In this case, the right brain (which gets info from the left side of the visual field) sees the bottle but has no language to respond. The “speaker” (which is the left brain) has no access to info about the bottle and can’t say “bottle”. But once there are 3 objects, the right brain remembers the bottle and points to it. At this point, the left brain sees that the bottle has been pointed at and confabulates, ie. concocts a plausible story to justify the person’s action. An even more interesting thing is that the 2 hemispheres often find backdoor ways of communicating. Here, the left hand (ie. the right brain) might draw a bottle and then the left brain might look at it and say “you showed me a bottle”.
3. Capgras Delusion:Too weird even for a fake dialogue, this is the delusion that a loved one is an impostor who looks and behaves exactly like the “real” loved one, but isn’t. People suffering from this condition have even killed their spouses, believing them to be robots. The explanation seems to be that when you see a person there are 2 systems at work: the first recognises someone’s physical/facial features while the second generates the emotional response to the person (ie. your liking/antipathy to them). For Capgras patients the two systems aren’t communicating properly. So you recognise that someone looks like your spouse (or pet!) but you don’t feel the familiar emotional response. The brain draws the only conclusion it can: it confabulates that this person really does look like the loved one but is not — hence an impostor, possibly a craftily-made robot.
4. Korsakoff’s syndrome (amnesic-confabulatory syndrome):
   Doctor: Can you please fill out this form so I can organise your medication?
   Patient: Sure! (Fills out form for a few minutes). Hey John, what do you think mum will think once the loan application is approved?
   Doctor: I’m sorry?
   Patient: She’ll finally get a place of her own!
   This tragic condition was very well-described in the chapter called The Lost Mariner [EDIT: A Matter of Identity — The Lost Mariner described a slightly less tragic version of the case with no confabulation] in The Man Who Mistook His Wife For A Hat by Oliver Sacks. The condition is caused by extremely severe alcoholism and results in the inability to form any medium-to-long term memories. You remember things from your childhood and onward (possibly up to the onset of the condition?) and you remember what happened 30 seconds ago. That’s it. Losing your memory in such a drastic way is like losing your very self, it is losing your narrative centre. This is not something you can do without, so the brain constructs a narrative, again by confabulating to explain what’s happening in front of you. In my made-up example, the patient did not remember why he was filling out a form and so “realised” it must have been him talking to his loan consultant about a mortgage. The real-life story had an even more tragic monologue with several confabulations in every sentence, and no seeming regard for consistency of the narrative, all while the patient remained perfectly jolly. And this is something we will all do if placed in the same situation of such severe amnesia.
5. Anton-Babinski Syndrome (blindness denial):
   Doctor: I’m afraid the medical results are certain. Your visual area is completely impaired. You are blind.
   Patient: What are you talking about? I can see perfectly well. Oh, is that you sis? Let me give you a hug. (Stands up and walks across the room stretching out her arms to nobody and bumps into a table.) Ouch! I guess I had a bit too much to drink at lunch. Okay, I’ll see you later then. (To doctor) I guess I better talk to her a bit later, when I’ve sobered up.
   Here the patient is blind but vehemently denies it. It seems that the parts of cognition that are affected aren’t just the ones that process visual imagery, it’s those parts that are expecting visual imagery in the first place! Any inconsistencies between the patient’s insistence they can see and behaviour are again confabulated away. The alternative is that the whole thing is a confabulation by the brain to avoid dealing with the idea that the patient is blind. In this case our patient may be making up an entire visual scene and believing she is seeing it. Bumping into objects while denying blindness and seeing people that aren’t present are normal reactions for this disorder.
6. Conversion Disorder (hysterical blindness):
   Doctor: I’m afraid the medical results are certain. Your visual area is completely normal. You’re not blind.
   Patient: What are you talking about? I can’t see anything. Can’t you run further tests?
   Doctor: Well, let me show you a pack of cards one by one. I want you to try tell whether each card is red or black.
   Patient: But what’s the point? I’m blind!
   Doctor: Humour me.
   Patient scores significantly worse than chance, getting say only 30% of the card colours wrong.
   This is the reverse of the previous condition: people who aren’t blind but are convinced they are. Doing worse than chance shows that at least some system in the brain is processing the visual information. It’s just that the information is then reversed — so as to make sure the wrong answer is given and the delusion allowed to persist.
7. Blindsight: A similar condition to the previous one. In this case, the patient really does have cortical blindness, so their ability to process image has been destroyed. However, other brain systems still make some use of visual information. When asked to “guess” the colour of a card they will get it right almost all the time — all the while claiming to be going off hunches whilst having no visual experience! (They aren’t in denial so there is no reversal to generate a wrong answer.) Some people have even been trained to use these “hunches” to basically get along much as a seeing person would. So imagine you have no experience of seeing anything but just get a feeling that the person you are talking to has just extended his or her hand for you to shake. You reach out and the real handshake occurs. Bizarre…

Truly our minds aren’t unified selves having a conscious experience but mazes of systems which sometimes talk to each other but sometimes don’t. When they don’t, confabulation, shortcuts, rewiring or denial are the standard solution for the evolutionary hacks that our brains are.