Hallucination, reveals our mind.

Neurologists and author

Oliver sacks brings our attention to Charles bonett syndrome

We see with the eyes but we see also see with the brain. And seeing with brain is often called imagination. And we are familiar with the landscapes of our imaginations, our inscapes. We have lived with them all our lives. But there are also hallucinations as well, and hallucinations are completely different. They don’t seem to be of our own creations. They don’t seem to be under our control. They seem to be coming from outside and to mimic perception. Here Oliver sacks is going to talk about hallucinations, varoius types of hallucinations.

What are hallucinations? Why do we get hallucinations?

There are many different types of hallucinations. And a particular sort of visual hallucination. An , old lady, Rosalie, a patient of mine, started experiencing visual hallucinations. When she has been completely blind from macular degeneration for last five years.

I went into see her. It was evident straight away that she was perfectly sane and lucid, and of good intelligence, but she has been very startled, because she’d been seeing things. So I said,”What sort of things?” And she said,”People in eastern dress, in drapes walking up and downstairs. A man who turns towards me and smiles. But he had huge teeth on one side of his mouth. Animals too. Then one night the scene changes i see cats and dogs walking towards me and then stop at a certain point. Then changes again, I see a lot of children walikng up and downstairs, they wear bright colours, rose and blue, like eastern dresses”. So I said, “Is this like a dream?”

She said,”No, it’s not like a dream, it’s like a movie, a silent movie and she said it’s rather one of the boring movies.” These hallucinations are completely unrelated to any thing she was feeling or doing, they seem to come on by themselves and disappear. She had no control over them.

On one occasion one saw, a man in a sriped shirt in a restaurant. He turned around and then, he divided into six figures in striped shirts, who started walking towards her. And then the six figures came together again, like a corcentina. Once, when she was driving or rather her husband was driving the road divided into four, she felt herself going up simultaneously up four roads. These are the examples of very mobile hallucinations. Sometimes she sees a teenage boy sitting on the hood of the car. And when they came to a stop, boy would do a sudden vertical take off about 100 feet in the air and then disappear.

This another woman has another different type of hallucinations, she was fine with her sight but, the visual parts of her brain, , little tumor in the occipital cortex. And above all, she would see cartoons. These cartoons would be transparent and would cover half the visual field like a screen. And especially she saw cartoons of Kermit, the frog. She said,”Why Kermit? Kermit, the Frog means nothing to me.”

But what did disturb her was the persistent, continuous images or hallucinations of faces, and the faces were often deformed, of very large eyes or teeth. And these frightened her.

Well what is going on with these people?

The tough part in this is reassuring people, that they aren’t going insane. And about 10 percent of the visually impaired people get these. But not more than 1 percent of the people acknowledge them, because they are afraid that they will be seen as insane or something. And if they do mention to their doctors, they might be misdiagnosed. In particular there’s a notion that if you see things or hear things, you’re going mad. But these psychotic hallucination are quiet different. Psychotic hallucinations whether they are visual or vocal, they address you, they accuse you. They seduce you, they humiliate you. They jeer at you. You interact with them.

There’s a film, you are seeing a film which has nothing to do with you or that’s how people think about it.

Temporal lobe hallucinations

There is also a rare thing called temporal lobe epilepsy, and sometimes if one has this, one may feel oneself transported back to a time and place in the past.

You’re at a particular road junction. Smell chestnuts roasting, hear the traffic, all senses involved, waiting for your girl. And it’s that day, back in 1982. And the temporal lobe hallucinations are all senses hallucinations, full of feeling, full of familiarity, located in the space and time, coherent, dramatic.

Charles bonnet hallucinations

Charles bonnet hallucinations are quiet different. So, in charles bonnet hallucinations, you have all sorts of level, from geometrical hallucinations to pink, blue squares up to quiet elaborate hallucinations with figures and especially faces, and sometimes deformed faces, are the are the single commonest thing in these hallucinations. And the second commonest is cartoons.

So, what’s being going on?

Fascinatingly, in the last few years, it is possible to do functional brain imagery, to do fMRI on the people as they are hallucinating. And, to find the different parts of the brain are activated as they are hallucinating.

When people have this geometric hallucinations, primary visual cortex is activated. This is the part of the brain that perceives edges and patterns. You don’t form images in this part of your brain. When images are formed a higher part of visual cortex is involved in the temporal lobe. And in particular one area of the temporal lobe is called the fusiform gyrus. And it’s known that people have damage in their fusiform gyrus, they may losse the ability to recognize faces. But if there’s abnormal activity in the fusiform gyrus, they may hallucinate faces, and this is exactly what you find in some of these people. There is an anterior part of this gyrus, where teeth and eyes are represented, and that part of the gyrus is activated when people get deformed hallucinations.