Tag: neuro

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Goat brains

Most amusing question asked at the BA Festival of Science: “Do people who ate goat brains when they were young get schizophrenia?”

This was at a panel session of top UK psychologists and neuroscientists. After the laughter died down, one of the panel members volunteered, “I ate goat brains when I was young.” A few seconds later, another said, “So the answer would be ‘yes’ then.”

(I hasten to add that people weren’t laughing at the questioner, but at the random and faintly absurd nature of the question, thus I still am a nice guy).

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Kurzweil and AI

Hah, I always knew that AI pundit Ray Kurzweil was up to no good, but this article proves it. Kurzweil is fond of making grand – and vague – predictions about the future of AI, but as far as I can see he his only major achievement that could possibly be related to AI is his voice recognition software – and Kurzweil was hardly the only pioneer in that field.

I was present at the unveiling of the Ramona prototype discussed in the article, and I was extremely underwhelmed by it. This lash-up of motion capture, voice recognition and crude AI was supposed to be a breakthrough? That Kurzweil’s estimate of the ‘virtual personality’ market being $5 billion in a mere three years turned out to be completely wrong is sadly no surprise to me now.

On a more general note, I’m glad that the article pointed out that, “absent multiple major revolutions in both computer science and neuroscience, it’s almost certain that the bold AI prognostications of today will be no more accurate than those of the past,” – the assumption that AI progress will continue to roll on ahead just like Moore’s Law exhibits a fundamental misunderstanding of the problems involved in artifical and human intelligence.

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Change Blindness

Change Blindness is an interesting psychological phenomenon that’s attracting a lot of research these days. There are a number of theories about why it occurs, and from a quick look at the literature I’m inclined to think it’s something to do with the role of attention and something called re-entrant processing.

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Armchairs and onions

One of the great things about being in UCSD right now is that I get to go to any classes I want, free of charge (unlike the poor saps who have to pay hundreds of bucks for the privilege – of course, they need course credit…). So at one of the recent cognitive neuroscience classes I went to (they’re really lectures), a guest speaker was there – a philosopher-turned-neuropsychologist.

During his lecture, one of the most amazing things happened. I didn’t fall asleep. Granted, I did doze off for a few seconds during the previous speaker’s lecture, but even so. Anyway, this ex-philosopher was talking about that old chestnut, the mind body problem, and also of course qualia.

I was expecting that I wouldn’t hear anything that was particularly new to me, since this was essentially an introductory one hour lecture and I’ve read a few books by people like Dennett that cover the same sort of material. Luckily, I was wrong. The first thing that caught my attention was the speaker’s listing of two conceptions of philosophers, the armchair conception and the onion conception.

The armchair conception is what we traditionally think of philosophers as; people who seek to answer questions a priori, that is, without experience of the matters in question. This means that, surprisingly enough, they can do everything from their armchairs. Scientists on the other hand act a posteriori, by conducting experiments and looking at the world.

The problem with this, the speaker argued, is that many philosophers such as Aristotle and William James defied the armchair classification because they did conduct experiments. Aristotle, for example, had a great interest in biology and went around dissecting things to find out more about them. So to accommodate this, there’s the onion conception. In this, the area of knowledge and questions that philosophers address is continually shrinking inwards, and as it shrinks, the layers it sheds become new disciplines that are more capable of addressing those questions that philosophy alone cannot. One of the first layers to be shed would be mathematics, and then subsequently disciplines such as biology, physics and so on.

One of the latest disciplines to be shed is psychology, which didn’t even exist separately until around one hundred and fifty years ago. Psychology and the now related area of neuroscience are now thus capable of better investigating the nature of the mind body problem, qualia, consciousness and all the rest.

Another great thing about being in UCSD is seeing the heavyweights of psychology and neuroscience plan their strategies and arguments. A couple of days ago I was having coffee with Prof. Ramachandran and a few others, and we were discussing how to pin down Damasio’s somatic marker theory, which is a hot topic in psychology and is regularly taught in psychology courses across the world. It struck me then, that, wow, this is how and where science gets made.

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Rez

Some good news in the lab, amidst all the unending software issues: one of the students may be bringing in Rez tomorrow (the famous self-styled ‘synaesthesia’ computer game) for the interests of ‘research’. Yeah, right. Naturally, I’ll have to demonstrate to the other lab members exactly how much research I’ve done into this important phenomenon…

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Synaesthesia

People might be wondering what it is that I’m doing in San Diego, beyond my rather nebulous description of ‘research’. Right now I’m working in the research labs of V. S. Ramachandran at the University of California, San Diego Center for Human Information Processing on an experiment to investigate an interesting condition called synaesthesia. Synaesthesia is basically what happens when your senses get mixed up and interconnected in strange ways. For example, when some synaesthetes read letters or digits, they’ll see them coloured (even when they don’t originally have colours). Others will associate sounds, music, shapes or even people with colours or smells. Essentially, any combination of the senses is possible, although grapheme-colour synaesthesia (a grapheme is a character) is the most common.

Estimates of the prevalence of synaesthesia vary from 1 in 200 to 1 in 20,000. The people in the lab I’m working at tend towards the former number. If that’s the case, chances are that you know someone personally who has synaesthesia – the only problem is that synaesthetes are either embarrassed about talking about their experiences, or they simply think that everyone is like them. One day the graduate student I’m working with was talking to a friend about a synaesthete who, when listening to speech, would see the words scroll along the bottom field of his vision, like subtitles. The friend said, “But doesn’t everyone have that?”

It’s generally thought that synaesthesia has a significant genetic component, and because it tends to be passed along the female line, it probably resides in the X chromosome. For a long time it was believed this couldn’t be true because Vladimir Nabokov had synaesthesia and so did his son Dmitri – so this meant that it couldn’t be in the X chromosome (sons inherit only the Y chromosome from their fathers). Of course, it turned out that Nabokov’s wife was also a synaesthete.

Why is synaethesia a big deal all of a sudden? Synaesthesia was ignored for a long time by psychologists due to the long-lasting age of behaviourism (‘don’t listen to what the subject says, just measure him’), and in any case many people simply thought synaesthetes were speaking metaphorically, e.g. “This cheese has a pretty sharp taste.” A series of pioneering experiments conducted over the last ten and twenty years have completely reversed this, showing that not only is synaesthesia a genuine phenomenon, but it’s also a perceptual one. By this, I mean that synaesthetes really see (say) colours when they see numbers. It’s not that they have an eidetic memory and can learn the sensory associations, they really experience them.

This has resulted in some interesting findings. Synaesthetes appear to have superior memory, and their ability to associate senses makes for good artists and writers. One of the things we’ll be doing in the lab is to talk to a trilingual synaesthete who experiences colours when she hears words – will the same word in the different languages elicit the same colour? Or will the phonological properties of the word – the sound of the word – matter more than the semantic meaning?

The point behind all of this is not merely to have a look at an interesting new condition. Synaesthesia also promises to shed light on some of the more profound questions about attention, perception, information processing in the brain, and consciousness. As such, it’s a very ‘sexy’ new topic and researchers are flocking towards it. It’s already been featured in a computer game, Rez (which is also very fun) and the other day I saw a mention of it in a Stephen Baxter SF novel. The main thing I’m working on here is a metacontrast experiment that’s aiming to find out exactly when the experience of colour occurs in the processing of visual information in synaesthetes. It’s a useful experience for me, especially given that many key findings about synaesthesia were made by people in the lab I’m in now.

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Probabilities

(Warning: Ramble ahead)

Earlier today, I was listening to a guy describe a project I might do next year for neurobiology, trying to figure out some of the characteristics of Golgi neurones in the cerebellum. The way you can identify these neurones, other than looking at them under a microscope, is to insert a super-thin electrode into them and look at their electrical activity. We’ve all seen what heartbeat readouts look like on TV, like a sharp spike. Well, the electrical output from neurones tends to look like that as well. Different types of neurones exhibit different and unique spike properties, such as spike magnitude, length, and interspike intervals.

So you can identify Golgi neurones by looking at their electrical readouts. This can take a bit of time, having to look back and forth all the time. What many researchers do is to hook up the output signal from the electrode to a loudspeaker, so each spike makes a click. I’m told that in time you can become extremely proficient at identifying different types of neurones very quickly by simply listening to their activity.

This kind of process is of course pattern recognition, and it struck me how skilled humans were at doing this and recognising and distinguishing new types of patterns. To do a similar thing on a computer right now would require a fair bit of coding – it wouldn’t be impossible by any means, and it might not be that difficult. But it would probably take longer than learning it yourself. That’s not to say that doing it on a computer is a waste of time, clearly if you want to automate the neurone-finding procedure and link the electrode position controls to the computer it’s worth it.

Even a computer wouldn’t be able to identify the type of a neurone with perfect accuracy though – neurones aren’t perfect things. It could give you probabilities though. And this set me onto a completely different train of thought. Usually probabilities of events or identification are shown in a numerical or percentage quantity, e.g. it’s 80% likely that it will rain tomorrow. Unfortunately, it seems that humans aren’t all too good at assessing probabilities – for example, it’s been shown that we ignore Bayes theorem while calculation probabilities ourselves.

We don’t say to each other, I think there’s an 80% probability of it raining tomorrow. We say, it’s a fairly good chance that it’ll rain tomorrow. And I think that people would respond to this type of framing probabilities better than numerical ways, in various circumstances. It just makes it more familiar.

And then I realised that we aren’t too hot on judging probabilities that way either, since according to human signal detection theories we can alter our criterion for the probability of events depending on, basically, how we’re feeling. And then I started writing this, and unfortunately I don’t have anything more to say at the moment.

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Emotions

While I have some issues with neurobiology lectures, I definitely don’t with our supervisions. They’re usually a great mixture of brainstorming and learning of interesting facts.

Take, for example, today, when I learned that when cats are hostile to each other and their hair stands on end, it’s because their hair makes them look much bigger than they really are.

Also, our supervision posed the interesting question – if squirrels didn’t have to forage and store hundreds or thousands of nuts over the winter and instead could get them from the supermarket, as we do, how would that impact on how closely their functions of consummation and apetite were entwined?

And why do foxes, when entering a barnhouse full of hens, kill every single one but only take one (or none!) off with them to eat?

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Neuro and Psych

There were two things that caught my attention today in lectures. The first was a list of symptoms of mania (an abnormal emotional state, the opposite of depression):

i. Unfounded elation
ii. Hyperactivity
iii. Talkativeness and “flight of ideas”
iv. Distractivility
v. Impractical, grandiose plans
vi. Inflated self-esteem
vii. Reduced sleep

…and I thought, ‘I wonder if I know anyone who has those symptoms…’

The other thing that caught my eye was this passage from a lecture handout:

If the brain was organised logically and economically, then the neural systems responsible for the control and initiation of writing should be located close to the primary langauge systems. Therefore hand dominance (left or right handedness) and language laterality (whether your language centres are located in your brain’s right or left hemisphere) should eb tightly correlated, with the dominant hand being contralateral to the language dominant hemisphere.

If you got all of that, good. But I have some real problems with that passage. Firstly, we only started writing a few thousand years ago, and indeed literacy only became widely prevalent in the last couple of millenia, so frankly writing could not have had any realistic impact on human evolution. Note that I’m only talking about writing, I’m not talking about hand dominance (e.g. which hand you throw with, which hand you use for complex tasks) which incidentally would make much more sense.

Secondly, what’s all this talk about the brain being organised logically and economically? Evolution is a powerful thing, to be sure, but it’s not perfect and it’s entirely possible that there are many good reasons why the language systems would not have to be next to the writing (or dominant hand control) centres. In fact, as far as I can tell, there are only two reasons for why people believe this. The first is that there is a significant correlation between language system lateralisation and dominant hand control lateralisation.

The second is that some people thing, ‘Well, language is a complex task and so is hand control. They both need lots of processing power, so obviously they should be put in the same place.’ This argument is so terrible that I need not discuss it further.

Anyway, I suspect that all of this is down to the lecture handout being rushed, but I do wonder if lecturers realise that making even the smallest typo or factual error in their handouts can cause unlimited amounts of grief to all revising students.