But there are also hallucinations as well, and hallucinations are completely different.

His grandfather had these hallucinations.

So in the Charles Bonnet hallucinations, you have all sorts of levels, from the geometrical hallucinations the pink and blue squares the woman had up to quite elaborate hallucinations with figures and especially faces.

And I see the geometrical hallucinations.

And the temporal lobe hallucinations are all sense hallucinations, full of feeling, full of familiarity, located in space and time, coherent, dramatic.

She had very mobile hallucinations as well.

They are visual, auditory, reading and writing and kinesthetic.

She wasn't on any medications which could produce hallucinations.

Now you might think, ah, there s a solution hallucinations.

This is a block diagram of a model and simulation of the human auditory cortex that actually works quite well in applying psychoacoustic tests, gets very similar results to human auditory perception.

We are not passive exhibitors of visual or auditory or tactile images.

About 10 percent of the hearing impaired people get musical hallucinations.

And about 10 percent of the visually impaired people get visual hallucinations.

Faces, and sometimes deformed faces, are the single commonest thing in these hallucinations.

When people have these simple geometrical hallucinations, the primary visual cortex is activated.

So for whatever reason, this implant is not successfully stimulating auditory cortices during melody perception.

She said she didn't recognize any of the people or places in the hallucinations.

Psychotic hallucinations, whether they are visual or vocal, they address you. They accuse you.

There is none of this quality of being addressed with these Charles Bonnet hallucinations.

And then I'm going to finish up with another example of this with audio auditory illusions.

You have the green for example, that corresponds to tactile information, or the blue that corresponds to auditory information.

It's typical of these hallucinations that they may come in a flash and disappear in a flash.

Now, I'll prime your auditory part of your brain to tell you what you're supposed to hear, and then hear it again.

This is the area where primary auditory processing so you're hearing my words, you're sending it up into higher language processing centers.

In fact, neuroleptic drugs that are used to eliminate psychotic behavior, things like paranoia, delusions and hallucinations, these are patternicities.

There must be hundreds of thousands of blind people who have these hallucinations, but are too scared to mention them.

There's sensory evidence you can use visual information auditory information, and that might tell you it's going to land in that red spot.

We have a very small amount of bandwidth for processing auditory input, which is why noise like this is extremely damaging for productivity.

So I am going to be talking about hallucinations, and a particular sort of visual hallucination which I see among my patients.

But sometimes he wasn't sure whether he was hallucinating or not, because the hallucinations would fit in the context of the visions.

In particular, the notion is that if you see things or hear things, you're going mad, but the psychotic hallucinations are quite different.

She said that the hallucinations were unrelated to anything she was thinking or feeling or doing, that they seemed to come on by themselves, or disappear.

Dr. Hemingstam, a psychiatrist, stated that his symptoms were characterized by difficulties in concentrating lack of appetite feelings of agony restlessness nightmares and hallucinations with impulses to commit suicide.

There is an area in the anterior part of this gyrus where teeth and eyes are represented, and that part of the gyrus is activated when people get the deformed hallucinations.

Charles Bonnet said, 250 years ago he wondered how, thinking these hallucinations, how, as he put it, the theater of the mind could be generated by the machinery of the brain.

But what did disturb her was she got very persistent images or hallucinations of faces and as with Rosalie, the faces were often deformed, with very large teeth or very large eyes.

And of course consider images that can be sensory patterns, visual, such as you're having right now in relation to the stage and me, or auditory images, as you are having now in relation to my words.

And he said, Yep. We accept that Tony faked madness to get out of a prison sentence because his hallucinations that had seemed quite cliché to begin with just vanished the minute he got to Broadmoor.

It's because you're all doing a cross model synesthetic abstraction, meaning you're saying that that sharp inflection ki ki, in your auditory cortex, the hair cells being excited Kiki, mimics the visual inflection, sudden inflection of that jagged shape.

There is about 20 regions of the brain that have been modeled, simulated and tested the auditory cortex, regions of the visual cortex cerebellum, where we do our skill formation slices of the cerebral cortex, where we do our rational thinking.

So the same strategy that we used to find the code for the retina we can also use to find the code for other areas, for example, the auditory system and the motor system, so for treating deafness and for motor disorders.

Neurologist and author Oliver Sacks brings our attention to Charles Bonnet syndrome when visually impaired people experience lucid hallucinations. He describes the experiences of his patients in heartwarming detail and walks us through the biology of this under reported phenomenon.

As the baby hears a word in her language the auditory areas light up, and then subsequently areas surrounding it that we think are related to coherence, getting the brain coordinated with its different areas, and causality, one brain area causing another to activate.

This, of course, is a visual map that I'm showing you, but this applies to any kind of map auditory, for example, in relation to sound frequencies, or to the maps that we construct with our skin in relation to an object that we palpate.

Now if you look at the brain of an individual who has a cochlear implant and you have them listen to speech, have them listen to rhythm and have them listen to melody, what you find is that the auditory cortex is the most active during speech.