Do we have a soul?

It is easy to get lost in a discussion about the existence or nonexistence of the soul. However, quite frequently conflicts do not arise because people disagree, but rather because they are using different definitions of the soul. Depending on the definition used I either believe or do not believe in the existence of a soul. A common though not very useful definition of "the soul" is what we really are, the core of our selves, or something like that. I would perhaps be inclined to call this "personality" rather than soul, but if that is what is meant by soul then yes, I think I do have one.

If on the other hand the soul is seen as something which is necessarily immaterial, then I do not believe in it. Hypothetically, should someone make an exact replica of me, with the exact same atoms in the exact same places, nothing more would be required. The replica and I would be impossible to distinguish from each other. The replica would react to any stimuli like me, would have the same childhood memories, be attracted to the same things, and just like me the replica would be disgusted by the smell of an orange.

This would not last long though. If me and my replica would continue our lives, then gradually subtle environmental differences would form us in non-identical ways, resulting in some small differences. These differences would ultimately affect the choices of me and my replica and consequently our preference would diverge. This, in turn, would lead to escalating environmental differences and increasingly different personalities or, if you prefer, souls. The resulting differences between me and my replica would be reflected in the way our atoms are put together, so we would no longer contain the exact same atoms. Nevertheless, there would probably be many striking similarities as well. There are examples of genetically identical twins that have grown up in very different environment, and still similarities have been extremely apparent.

What do I base this belief on? My main piece of evidence is that there does not seem to be any part of the personality that cannot be affected by brain injury. In my neuropsychology course I read about many patients with exotic brain injuries. A famous patient called HM, who is still alive, is unable to form any new memories. As a result he still thinks that he is 25 years old and he does not recognize the researchers who have visited him every day for several decades. Another older case is that of Phineas Gage who got a metal stick shot up through the frontal part of the brain. To everyone's amazement Gage did not die from the injury, however, according to his colleagues he was not the same after the injury. Following the injury he started swearing and behaved inappropriately to the extent that he lost his job. However, the most striking case that I can remember only vaguely is that of a responsible normal woman with three kids. Due to a tumor in her brain she suddenly underwent a radical personality change. Her behavior went from normative to completely reckless, and from being a good and faithful wife, she became extremely uninhibited and promiscuous…

One needs merely to take a look at a severe case of Alzheimer disease to see that material changes in the brain can change a person beyond recognition. Some would say that there is always something left, that even though Anna is now eating her own feces and hitting her children when they come to visit, she is still Anna, somewhere inside. I don't think so. Sure, she is still called Anna, and one can still recognize her appearance, but other than that Anna is not Anna anymore. The soul of Anna is very different from the soul Anna used to have before she got Alzheimer.

In sum, due to the fact that there seems to be no sacred part of the personality, nothing which cannot be affected by changes of a material nature. Due to this I do not believe that we have an immaterial soul. Normally I try to avoid the word altogether because of the confusion that arises, but this is my current thoughts on this issue. The discussion here has many important implications, for instance it should affect how to think about free will vs. determinism. I have written about that here.

Learning described at the cellular level: Finding from our laboratory in Lund

Today I want draw the attention to some very exciting discoveries from our neurophysiology laboratory here in Lund. Because I have just started working in the lab I cannot take any credit for the work, though I have been spending a lot of time lately, trying to develop the experimental setup further. Instead it is Dan Anders Jirenhed, Fredrik Bengtsson, and Germund Hesslow who have worked for several years to achieve the experimental setup that allowed the findings that you can read about here.

The findings have already received quite a lot of attention from places with more readers than my blog. See for instance the article in New Scientist, or if you understand Swedish you can listen or read about the discoveries on Sveriges Radio homepage. If you are interested in the technicalities I recommend that you read the original article which was published in the Journal of Neuroscience.

What has been found is a perfect correlate between behavioral learning and cellular behavior. To explain what this means you first have to know what classical conditioning is. To understand what classical conditioning is, imagine that you sit in a comfy chair (doesn't really matter whether it is comfy or not). Suddenly you hear a loud tone, and immediately after that you get a puff of air in your eye. If you have a normal brain you will blink when your eye is hit by the air. Now imagine that this occurs over and over again, first the tone, then the unpleasant air puff. Again, if you have a normal brain it will eventually realize that "aha, if I blink when I hear the tone, I can avoid that nasty puff of air in my eye, I think I will do that".

Though you may be conscious of the association between the tone and the air puff, this type of learning does not take place in the cortex of our brain, but rather in the cerebellum. Take away the cerebellum and this type of learning is severely impaired if not entirely abolished. In our laboratory we used tiny winy electrodes to measure the activity of single purkinje cells (see picture) in the cerebellum while presenting tones and air puffs. Purkinje cells are a type of neuron located in the cerebellar cortex (near the surface), which because of their morphology appear to be particularly good candidates for the learning that occurs during classical conditioning.

So in essence we could see what happened to the activity in this single purkinje cell when we were applying a classical conditioning paradigm (presenting tones and air puffs). If you just leave them alone, purkinje cells will fire action potentials at a rate of about 60Hz (60 times every second), however, amazingly during the learning paradigm described above the purkinje cells started to show a very distinct pause just prior to the presentation of the air puff (see picture). Change the time lag between the tone and the air puff, and the timing of the pause in the purkinje cell will change so that it is always perfectly synchronized with the air puff. Eliminate the association between the tone and the air puff by presenting only the tone without the air puff and the pause will disappear. Re-establish the association between the tone and the air puff and the pause in the purkinje cell will rapidly re-appear. In essence there is a perfect agreement between the behavior of the animal and the behavior of the purkinje cell.



So why is this so important? Well first of all it is just super interesting, I mean it appears that we can start to describe learning in terms of patterns of neuronal firing. This also means that we will soon be able to see what happens to learning during different treatments. One question that I find interesting is what would happen to the activity in the purkinje cell if we squirt some narcotics (e.g. Cannabis) onto the cell. Will the learning be damaged in some way. There are probably millions of follow up questions that we can now start to explore. All this because of the work done here in Lund, Sweden.

True cyborgs now a reality!

Muscular movements are controlled by the central nervous system. Right now my brain is actively planning the muscular contractions that will make my fingers exert a force on different buttons on my keyboard, ultimately resulting in the text that you are hopefully enjoying right now. How does this work? Well, there are many unsolved mysteries, but we have also learned quite a lot.
Two areas of the brain, the "supplementary motor area" (SMA) and the "premotor area" (PMA), seems to be involved in planning the exact series of muscle contractions that are required in order to do something such as writing this text. How do we know this? Put a person in an fMRI machine and ask them to imagine doing something, and wallah, SMA and PMA lights up (meaning that more blood is going to these areas, mening that more glucose gets there, meaning more activity in those cells)! In order to actually move you will also have to get your motor cortex involved. It is from this area that axons travel down into the spinal cord and elicits movements. If you stimulate the motor cortex electrically during a surgery (this is sometimes done to see how the body is mapped onto the motor cortex), then the corresponding muscles will contract, perhaps resulting in an arm or a leg flapping out. So when your SMA and PMA have planned the contractions they will communicate with the motor cortex which then sends signals down to the alpha motor neurons in your spinal cord which in turn will release acetylcholine onto the muscles causing them to contract. All this happens within a few milliseconds! (Of course other areas such as the basal ganglia and my own darling, the cerebellum are also involved in movements, this was merely a simplified account.)

Who cares?, where are the applications? Back in 1982 a guy named Georgopoulos measured the activity in the motor cortex of a monkey while it was performing some well defined motor tasks. Georgopoulos found that a certain movement would be associated with a particular pattern of activation in the motor cortex. Thus, merely by looking at the activation in the motor cortex he could predict that the monkey was trying to move say, its left index finger. This could be very useful for people suffering from paralysis. Theoretically it should be possible to measure motor cortex activity and from that see what movements the motor cortex is trying to do. Then, to help a paralysed patient what you need to do is to connect a robotic arm programmed to move in response to neuronal activity. This procedure is no longer science fiction, it is reality. In this article it is described how some surgeons used signals coming from the motor cortex to make a prosthetic arm move, in other words they made a true cyborg out of lucky Mitchell, 24.

Although I am pessimistic about the prospect of creating a brain that is as complex as our own I do think that in the future more and more applications like this one will appear.

Free will and determinism

Do we have free will, or are all our thoughts and actions a result of the physical forces in our universe?

After having taken part in a discussion about consciousness on Furiku's blog I decided to learn a little bit more about the philosophy of the mind which discusses such things as the nature of the mind, consciousness, and free will versus determinism. The audio-course, which I warmly recommend, is from the teaching company (see my previous post about the the teaching company here), and it is called "philosophy of the mind". Teacher is John Searle (see picture) from the University of California, Berkeley.

My experience is that the question of free will versus determinism is a question that many people ask themselves occasionally. Are we free agents in the world or does everything, and I mean everything have a preceding cause. I cannot speak for anyone else of course, but for me it sure feels like I have free will. When I write these words I feel as if I am deciding to write these words, and I can even erase them again if I want to! On the other hand, dwelling further into this I can think of situations in which I have felt as if I had no free will, where I acted contrary to the way I wanted to act. One of my stepchildren exemplifies this point well. In the process of doing something violent to her younger sibling she sometimes says "I just could not control myself", which effectively eliminates the possibility of telling her that "that was wrong!".

I should state here what I believe; I believe that we live in a determined universe, that free will is an illusion (that we are determined to have), and I will now explain why.

We have physical laws which can, with some small exceptions, explain more or less everything that goes on around us. In most chemical and physical systems we can, if we know the current state of the molecules in the system, predict how the same system will look in the future. Our brain is a chemical/physical system (a very complex one), and therefore it should be theoretically possible to predict what our brain will look like in the future, and if we had more knowledge about the relation between the physical and mental state of the brain we would be able to predict exactly, the mental states and behaviors of the individual.

Some people will object to my view by saying that, if I don't have free will, then everything is determined and it doesn't matter what I do. I could go out and rape and kill people and that would have been inevitable. However, if the deterministic hypothesis is true, then you could obviously not decide to go out and kill and rape. If you did go out to kill and rape, it would be because of something, maybe these words (caused by processes in my brain) have had an influence of your brain which makes you go and do this, or maybe you have gotten a tumor in your amygdala, messing up your emotions. A similar objection that I sometimes hear is the following. "How can you (referring to me), believe in such a depressing thing?" Life is meaningless without free will! Of course the answer is the same, if the deterministic hypothesis is true I cannot decide to believe or not believe in free will, my beliefs were determined by the state of the universe when it began. Besides, I don't really feel sad when I think that I have no free will, rather, I think, I am a little bit amused by this thought.

Another objection is that research in quantum mechanics have shown that there is uncertainty in the universe. We cannot tell the exact location of the electron when it is orbiting the nucleus of the atom, hence free will. To me this argument sounds rather far fetched and desperate. There is no plausible reason to suggest that we would be able to control, through our mental activity, where the electron is located, and there is also no good reason (as I see it), why the location of an electron in the orbital cloud should give rise to different actions.

Summing up, I just cannot see anyway around the conclusion that there is no such thing as free will. It free will did exist it would be a big problem for science which rests on the assumption that every process in the universe have a cause. I would love to hear comments on this post, especially from people who do believe in free will...

N400 and the beautiful is good stereotype continued, results from my current research

In a previous post I described my current research in which I tried to measure the beautiful is good stereotype using EEG. The idea is that when we are presented with something that contradicts our stereotypes, our brain says "wait a minute, those just don't go together, that is odd". It just so happens that there is an ERP component, called the N400, which is sensitive to mismatching stimuli.

So in my experiment, participants were presented with faces rated as either attractive or unattractive, followed by words rated as either positive or negative. Their EEG (their brain activity), was measured throughout the experiment. We expected to find that the magnitude of the N400 wave/component would be larger when presenting incongruous face-word pairs. Pairs that are incongruous contradict the stereotype, so in this experiment it would be attractive faces followed by negative words or unattractive faces followed by positive words.

So what did we find? Do our brains object when they see an attractive person followed by a negative trait or when an unattractive face is followed by a positive trait. In our experiment we found no N400 for attractive faces, however, we did find a clear effect for the unattractive faces. This supports the view that rather than having a "beautiful is good" stereotype we have an "ugly is bad" stereotype. Just to spell it out, our data showed that when the average participant was presented with an unattractive face followed by a positive word, the brain responded with a larger N400 component, indicating that there was a mismatch between the two stimuli, they did not go together. According to our data, it is much harder to imagine an unattractive person with positive traits than an attractive person with negative traits...

Another discovery that we made during the study is that there was a difference in the EEG that depended only on the type of face presented, that is the EEG activity following presentation of an attractive face is different from the EEG activity that follows the presentation of an unattractive face. Interestingly, the difference in EEG activity following presentation of either attractive or unattractive faces is highly similar to the difference that you see when you present pleasant or unpleasant stimuli. So it would seem that perceiving an attractive face will "reward" your brain. This is also supported by fMRI studies in which it has been shown that perception of attractive faces leads to activity in parts of our brain normally associated with reward.

If you are still curious and want a more complete description of the experiment you can download the entire article here.

The next step in our research is to investigate further what types of positive traits are associated with attractive and unattractive faces. A previous meta-analysis have shown that we associated attractiveness more with social competence than with intellectual competence. We are going to see whether this pattern we will also see this pattern when we measure the stereotype using N400. Furthermore, we are going to see if there is a link to memory. One could speculate that it is easier to remember face-word pairs that agree with our stereotype because we already have a developed network to store such information (or something like that). Or, alternatively, perhaps we remember incongruous information better because when we see something that does not agree with our stereotype we use lots of resources to reconcile it with what we know, and since the level of processing of a stimuli is correlated with how well we remember it, it is possible that we will remember incongruous pairs better. We will see...

Some interesting discoveries about pheromones

In order to prepare for my soon to start PhD studies, I have been reading a lot of neuroscience lately. I am currently reading a book called Neuroscience: Exploring the Brain by Bear et. al. (2006), a textbook that I warmly recommend to everyone interested in the field.

In this book there is a section about human pheromones which I found so fascinating that I thought I would share it with those few people who occasionally read this blog. Pheromones are basically small molecules that fall off us and are sometimes picked up by the nose of other people or (more likely) animals. Our pheromones tells our genotype and can work as a fingerprint even more accurate than the fingertip fingerprint. A bloodhound which has perhaps the most developed sense of smell of all animals has great difficulty in distinguishing between two identical twins. Fraternal twins on the other hand is piece of cake. An ewe will establish a life long memory of her lamb when it is born. Pregnant female mice will automatically trigger an abortion if they feel the smell of a male other than the one that impregnated her.

What about humans then. One rather well known, yet astonishing, effect of pheromones is the synchronization of women's menstrual period. When females are allowed to smell pads which have been under the arm of another female, their menstrual period will converge with the other females period. This happens even though the women do not feel any smell at all! Pheromones are also very much involved in our sex life, believe it or not. Evidence indicates, that by picking up pheromones we can sense whether the potential mate is a good match or not (in terms of genes). Napoleon (see picture) was probably one of the first people to realise what smells can do to your lust. He once wrote and asked Josephine not to bathe for two weeks(!), so that he could enjoy her aromas...

My current research project (fall 06) - Electrophysiology and stereotypes...

Since I am doing the "C-course" in psychology at Lund University, I am expected to carry out a research project. I was lucky to be allowed to use the rather new EEG lab that has been set up. This allowed me to do an experiment that I have been thinking about since the spring but which I have not had the chance to do until now

So what is my project about? I am actually trying to do something as sexy as measuring peoples' stereotypes using EEG. An EEG (see picture) measures the electrical activity that the brain generates. This electrical activity differs depending on what the brain is doing. If you are sleepy the brain will start to generate what is referred to as alpha waves (a funny consequence of this is that you can actually see when your subjects are starting to get fed up with your experiment), if you are dead there will be a straight line, an epileptic seizure is characterized by wild activity etc etc. In fact, the brain also generates characteristic wave patterns in response to certain events, these patterns are called event-related potentials or ERPs.

In my experiment I am looking at a specific wave called the N400, N because it is a negative deflection, and 400 because it occurs 400 milliseconds after the stimuli was presented. The N400 appears when our brain perceives something unexpected. For example, when the brain hears a sentence such as "Jack took the bus to town to meet some of his boxershorts", the brain says, wrooong!! (an N400 wave appears). Similarly, if famous faces from different occupations e.g. Robert De Niro and Billy the clown, are presented serially, the N400 also appears, thus suggesting that our brain has recognized that these two stimuli did not belong to the same category.

I am reasoning that stereotype incongruency, that is, things that go against your stereotype, will also elicit this N400 component. To test this prediction I have obtained a collection of attractive and unattractive faces as well as a collection of negative and positive words. Presumably the N400 component will appear when I present to my participants an attractive face followed by a negative word, or conversely an unattracitve face followed by a positive word. The reason I believe so is that there is a lot of evidence suggesting that we associate attractive faces with positive characteristics and unattractive faces with negative characteristics. To be continued...