Nicotine, appetite and the brain

Nicotine is not only very, very addictive, as a central nervous system stimulant it can also affect our motivations and behaviors in a wider sense. One of the behaviors it can modify is appetitive behavior. It's a well-funded fact that smokers tend to have a lower body-mass than non-smokers, and that smokers who quit have a tendency to gain weight, although until now the neurobiological mechanism for this modulation was unknown.

Recent findings from two different publications reveal parts of this mechanism, but while most reports have pin-pointed the results involving appetite suppression through pro-opiomelanocortin neurons, there is evidence that the complete picture is more complicated than that.

Update/A melatonin NGram

March and April disappeared in a daze and didn't lend me much time to spend on blogging. Finishing my teaching and course assistant duties for our undergraduate neurobiology course while re-working and re-submitting a research paper (now accepted in Endocrinology) took up most of March. Then to top things off I contracted a nasty Mycoplasma infection that left me floored with pneumonia for three weeks, including three days of hospitalization, so there went most of April. And the start of the year is a busy time for me as it is! I'm still a bit off-colour, but back to work!

I had started a big post about melatonin sometime in March to coincide with my lecture on biological rhythms on our neurobiology course, but as stuff happened I never actually finished it. As things have it though, I was asked to cover for another teacher lecturing last week about melatonin and the pineal gland for second term medical students, so I got a reason to re-visit melatonin and the blog post. I hope to have it up soon, but I haven't recovered completely and I'm still taking it easy with my work load so blogging is not really a priority right now. But as a short preface to that post, I thought we could take a look at what information we can extract about melatonin and the pineal gland from Google NGrams.



Melatonin is a hormone related to the neurotransmitter serotonin. Most people may have heard about it in the context of jet-lag or insomnia and perhaps different supplements or medications one might take to counteract them. Indeed melatonin is secreted when it's dark by the pineal gland in the brain as a general "night-time signal", although it doesn't stimulate sleep by itself.

We can see very clearly in the ngram above that "melatonin", "pineal gland" as well as the general term "pineal" have had a clear rise since the start of the 1960's. This makes perfect sense since melatonin was first isolated in 1958 from cow pineal glands. It was named and some of its effects were described in a 1960 paper by the same researchers. However, it was already known since the start of the 20th century that pineal gland extracts had some biological effects, before the hormone was isolated. This is detectable in another ngram, but could it also be related to the sharp peak in the term "pineal" that we see in the first decades of the 1900's in the ngram above?

The terms "pineal" and "pineal gland" go back quite far, reflecting the fact that the pineal gland has been known anatomically, and to some extent functionally, for quite a long time. The term "pineal body" is a bit of a curiosity since you often see it in old literature, but it doesn't seem to be as old or to reach the same prominence as "pineal gland" at all, which is surprising, at least to me. I thought that "pineal body" would be the older term and that it was eventually replaced by "pineal gland". Not so apparently.

Oxytocin, ethnocentrism and evolution (pt. 2)

>> Go here for part 1.

I didn't want to risk making my previous post too long, and I wanted to keep it focused on "hormonal determinism", so I set aside a whole branch of my commentary on the link between the hormone oxytocin and ethnocentrism for another post. The findings I comment on were presented by De Dreu and co-workers in the latest edition of PNAS (see reference below).

So, today I want to talk briefly about bad evolutionary arguments.

Oxytocin, ethnocentrism and "hormonal determinism"

>> Go here for part 2.

There is an inordinate readiness, both within scientific circles and in popular scientific understanding, to ascribe direct causation to the actions of hormones, especially when it comes to moods and behaviors. For example, consider how you’d usually interpret the common expression “being hormonal”. I consider the thought that hormones somehow “control” our moods and behaviors a falsehood; a popular misunderstanding or oversimplification that hinders the understanding of what’s actually going on. There is just as little motivation to call a hormone the “love hormone”, the “stress hormone” or the “sleep hormone” as there is calling a gene the “gay gene” or the “god gene” et c. The idea that in fact there is no one gene for property X, Y or Z has become pretty pervasive now, and I think it’s time the same thing happened for the actions of hormones.

Within this context, I want to use as an example a newly published study in PNAS that links the actions of the neurotransmitter and hormone oxytocin to ethnocentrism – the tendency to view one’s own group, the in-group, as more important or superior to other groups.


Molecular structure of human placental mammal, some marsupial, platypus, ratfish and elephant shark oxytocin.

Perhaps more than any other hormone, oxytocin has become the perfect example of the kind of “hormonal determinism” that I mention above: no doubt because the study of oxytocin is a very active field and because it’s been linked to some very fascinating behaviors.

Einstein's brain

Einstein's brain was photographed only hours after his death. Ref: Falk (see reference below)

Einstein's brain pops up quite often in popular science lore about the relation between brain size and intelligence. The most common myth (based solely on my own experience) is that Einstein's brain was smaller than average ergo brain size has nothing to do with intelligence. In actual fact, the size of Einstein's brain (as measured when retrieved shortly after his death at 76) was completely unremarkable for a male specimen of his age. As it turns out brain size is a lousy correlate of intelligence anyway, regardless of Einstein's brain. In my opinion it's probably only a great correlate of skull size. So it's less about how much you have and more about what you do with it. I usually bring this up when I lecture about the anatomy of the brain.

With that in mind, today I came upon a recent commentary on a study of Albert Einstein's brain published in Frontiers in Neuroscience last year. This re-analysis of the surface features of Einstein's cerebral cortex, using tools from the field of paleoanthropology, lead anthropologist Dean Falk to make new observations about Einstein's brain and the relation they might have had to his exceptional capabilities.

Reverse-engineering a brain?

>>I'm at a conference in Hungary, so this post is a little bit delayed from the original date I started to write it

If you've followed the debate that's been going on in the blogosphere, you know that Ray Kurtzweil, computer scientist, inventor,"futurist" and self-proclaimed prophet of "the singularity", recently proposed that it would be possible to reverse engineer a human brain - basically simulate it in a computer - within the next 20 years. Developmental biologist and blogger PZ Myers was not impressed and wrote a harsh and critical evaluation of Kurtzweil's arguments. So did other people: How to build a brain wrong, What Ray Kurzweil and geoengineering have in common, Reverse-Engineering the Human Brain? Really?, Baseless speculation variety hour.

Kurtzweil rebutted and Myers was quick to counter his claims once again.

Book tip in Swedish: Om hjärnan

I'm back from my 5 week vacation, only to be thrown right back into work. What can I say? There are articles to be submitted for review and conferences to prepare for so there is no rest for the wicked. It's all good though. I just wanted to pop in to give you a quick book tip and let you know what I worked on a lot earlier this year.

The publisher Fri Tanke is publishing parts of Oxford University Press' "A Very Short Introduction" series in Swedish translations, starting out with "The Brain: A Very Short Introduction", "Consciousness: A Very Short Introduction" and "Free Will: A Very Short Introduction". Find more info on Fri Tanke's website. I had the pleasure of assisting on the Swedish edition of "The Brain" by fact-checking the translation. See? That's my name on the copyright page below so you know I'm not lying. I even got a little biography blurb at the end of the book, and the opportunity to suggest some further reading.

I spent many an evening and sometimes many a sleepless night back in January and February working on this, and it's the first time I get to do something of this type, so I'm really pleased that the outcome turned out as good as it did. If you're looking for a comprehensive and easy to understand introduction to the brain in Swedish, I really can't recommend anything better. The book is called "Kort om Hjärnan" by Michael O'Shea and that's the very pink book cover at the top of the page. It came out while I was on vacation in June so I haven't had the time to really comment on it until now.



Swedish blog tags: Vetenskap, Neurovetenskap, Hjärnan, Boktips,
Technorati tags: Science, Neuroscience, Brain

"Why do we believe", and are atheists really more intelligent?

ResearchBlogging.org editor Dave Munger has written an article for SEED magazine entitled "Why do we believe". The article summarizes recent blog entries regarding studies on the origins of religiosity. It's really worth reading to get a good overview of the subject, and what do you know he links my entry on god's will and beliefs in it.

Among the studies that are mentioned is a controversial study entitled "Why Liberals and Atheists Are More Intelligent" (link at the end of this post).

Medical writer Tom Rees devotes his blog Epiphenom to the scientific study of religion. Last week he examined a study on the relationship between intelligence and religious belief. Published in Social Psychology Quarterly, this study by Satoshi Kanazawa replicated the results of several earlier studies in showing that strong religious belief was correlated with lower intelligence. In this case, adolescents who scored higher on intelligence tests were less likely to be religious as adults.

But Rees says Kanazawa’s study goes beyond those earlier studies to arrive at a potential explanation of why less-intelligent people are more religious: Intelligence evolved in order for people to adapt to novel situations.

You should go over to Epiphenom to read a summary of the study as well as my commentary on it, posted as a blog comment. In summary: I don't think it's very good. Kanazawa's evolutionary argument is completely based on some pretty wild conjectures and lacks any sort of empiric support. His argument is at most "sorta reasonable", but we must do better than that surely. For evolutionary researchers that have to spend considerable time and effort gathering a solid line of evidence, this sort of jumping to conclusions can be a tad annoying.

Also, let's remember what kind of forces we're dealing with here, how evolution through natural selection actually acts and what it acts on. Even if we assume first, that intelligence tests do measure some sort of good approximation of intelligence, and second, that results gathered today actually reflect a past situation; what difference do a "good few" average points make for survival? Any conclusions made from the correlation between higher intelligence, as measured by intelligence tests, and atheism are only significant within a larger evolutionary and functional neurobiological context. So take claims that atheists are more intelligent (on average) with a considerable pinch of salt.

Read more on the subject on Epiphenom, here and here.

Kanazawa, S. (2010). Why Liberals and Atheists Are More Intelligent Social Psychology Quarterly DOI: 10.1177/0190272510361602

Swedish blog tags: Vetenskap, Biologi, Neurovetenskap, Hjärnan, Religion
Technorati tags: Science, Biology, Neuroscience, Brain, Religion

God's will and beliefs are your own, not god's

I've written before about how religious beliefs probably are grounded in brain mechanisms that we use for other purposes, primarily social interactions. There is no "god spot" in the brain, rather we think of supernatural all-powerful agents much in the same way as we think of the people we interact with. It suggests that religious belief is a secondary effect of basic or general mechanisms that guide social cognition, although it is not definitely proven.

That study dealt with god's perceived involvement in the world and god's perceived emotion among other things - in a newer article published around christmas in PNAS a team of researchers have investigated how believers think when they think about god's will and god's own beliefs. The importance of such an investigation is highlighted already in the opening paragraph of the article.

Religion appears to serve as a moral compass for the vast majority of people around the world. It informs whether same-sex marriage is love or sin, whether war is an act of security or of terror, and whether abortion rights represent personal liberty or permission to murder. Many religions are centered on a god (or gods) that has beliefs and intentions, with adherents encouraged to follow "God’s will" on everything from martyr-dom to career planning to voting. Within these religious systems, how do people know what their god wills?

Since we already readily infer other people's beliefs egocentrically, that is as similar to our own - conservative people tend to gauge positively evaluated people as more conservative than progressive people do - it's justified to ask: How do your own beliefs guide your predictions about god's beliefs? Especially since we seem to think about god as we think about the people we interact with. According to these results believers project their own values and beliefs on their god (or gods) to a great extent, which could certainly help explain not only the great diversity and variability of religious belief and expression, but also the ambiguous nature of religious interpretation.

The paper includes several studies, among them several correlational studies using surveys where people were asked to estimate god's, the "average American's", Bill Gates', George Bush's (among other known figures) beliefs on several controversial subjects such as abortion and same-sex marriage, and an experimental study where the subjects' beliefs were manipulated through exposure to persuasive arguments in order to see if they "changed god's mind" as readily as they changed their own.

Most interestingly for me though, they also conducted a neuroimaging study, and since it's what I'm most familiar with I will focus on that. It consisted of 17 test subjects reporting their own attitudes on controversial subjects as exemplified above, as well as estimating the attitudes of the "average American" and god on the same subjects while in an MRI machine.

Below you see three images that highlight the differences in brain region activation (yellow/orange spots) when comparing the measurements done while stating your own attitudes vs. estimation of the "average American" attitude, estimation of God's attitude vs. the "average American" attitude, and most interestingly your own attitude vs. estimation of god's attitude.


Ref: N. Epley et. al. (see reference below)

As you can see, there is no difference between thinking of your own beliefs and thinking about god's beliefs, which stands in contrast with how it looks when you're thinking of another person's beliefs. Of course the image only shows one representative slice of the data, but the results were consistent across the panel. Thinking about god's beliefs seems statistically indistinguishable from thinking about your own beliefs, whatever your beliefs are.

The brain regions that were found to show differences in the self vs. American and god vs. American comparisons, and no differences is the self vs. god comparisons, include regions that are known to be involved in thinking about your own mental state and in the projection of your own mental states onto others. In a follow-up analysis the authors closed in on one of these regions, the medial prefrontal cortex, and observed that it had a significantly lower activity when thinking about the beliefs of the "average American" than when thinking of your own beliefs or those of god, which again were indistinguishable. Compare the three columns in figure B. BOLD is the measurement of blood oxygen level in the brain regions, which is a correlate of brain activity.

There is a growing body of literature showing that religious beliefs seem to emerge from the same neural substrates that produce a more general social cognition. The interesting point in these studies is that while we relate to the entity of god and experience god's involvement in the world much like we would that of another person, our estimations of god's will and beliefs are self-referential and egocentrically biased, more so than our estimation of other people's beliefs. Religiously motivated political, moral or social stances may originate just as much from your self as from others in your surroundings, like your parents or congregation. Indeed it only seems natural to assume that god has the same belief as oneself. God, as the supreme authority, must hold true beliefs and most people naturally presume that their own beliefs are true.

As an atheist one is often confronted with the view that without religion there would be no morality; that without religion humanity would degenerate. As a professed nonbeliever you're either an immoral degenerate or unconsciously religious. These data provide some evidence that morality and personal beliefs are native to human cognition and are largely independent from religious inputs.

People may use religious agents as a moral compass, forming impressions and making decisions based on what they presume God as the ultimate moral authority would believe or want. The central feature of a compass, however, is that it points north no matter what direction a person is facing. This research suggests that, unlike an actual compass, inferences about God's beliefs may instead point people further in whatever direction they are already facing.

PS: Just as a side note I want to mention that in one of the correlational studies they included nonbelievers. However the results were difficult to interpret. Nonbelievers seem to go less according to their own beliefs when estimating god's beliefs... which somehow makes sense but kind of doesn't prove anything. At least, the authors note, it demonstrates that you have to believe in god to make an egocentric estimation of god's beliefs in the first place.


Epley N, Converse BA, Delbosc A, Monteleone GA, & Cacioppo JT (2009). Believers' estimates of God's beliefs are more egocentric than estimates of other people's beliefs. Proceedings of the National Academy of Sciences of the United States of America, 106 (51), 21533-8 PMID: 19955414

Swedish blog tags: Vetenskap, Biologi, Neurovetenskap, Hjärnan, Religion
Technorati tags: Science, Biology, Neuroscience, Brain, Religion

What's up with new year's resolutions?

I've never been one for new-year's resolutions. Making up reachable realistic goals is of course great, as long as they're reasonable, and setting up more short-term goals that lead up to something, breaking down the thing you want to accomplish, seems like a reasonable thing to do. But there's something about new-year's resolutions that I just can't get over. Thinking that the act of making a resolution, preferably in front of others or by getting it down in writing, somehow will affect the outcome of the resolution positively, seems like wishful thinking. In other words: Just because you resolve or promise to do something, does not automatically mean you are going to be successful at it. Yet, this is what the brain is really good at thinking, especially when you link it to some sort of special date or event, like the onset of a new calendar year.

Thankfully, this isn't what most people mean by making new-year's resolutions, but it's the thought that underlies the cultural phenomenon. Most of us set goals throughout the year, not necessarily assigning a special significance to an arbitrarily set date. Even though gyms are never as full as in January, I don't think most people mean very much by making new-year's resolutions, or even expect to be all that successful.

Then there's the argument of willpower. How intelligent is it to bunch together all your goals for the year in one bundle? Especially when so many of our typical resolutions involve resisting those instantly gratifying things we love so much. This is the subject of an article by Jonah Lehrer (in keeping with my previous post) called Blame It on the Brain: The Science Behind Failed Resolutions.

Willpower, like a bicep, can only exert itself so long before it gives out; it's an extremely limited mental resource.

Given its limitations, New Year's resolutions are exactly the wrong way to change our behavior. It makes no sense to try to quit smoking and lose weight at the same time, or to clean the apartment and give up wine in the same month. Instead, we should respect the feebleness of self-control, and spread our resolutions out over the entire year. Human routines are stubborn things, which helps explain why 88% of all resolutions end in failure, according to a 2007 survey of over 3,000 people conducted by the British psychologist Richard Wiseman. Bad habits are hard to break—and they're impossible to break if we try to break them all at once.

The brain area largely responsible for willpower, the prefrontal cortex, is located just behind the forehead. While this bit of tissue has greatly expanded during human evolution, it probably hasn't expanded enough. That's because the prefrontal cortex has many other things to worry about besides New Year's resolutions. For instance, scientists have discovered that this chunk of cortex is also in charge of keeping us focused, handling short-term memory and solving abstract problems. Asking it to lose weight is often asking it to do one thing too many.

In one experiment, led by Baba Shiv at Stanford University, several dozen undergraduates were divided into two groups. One group was given a two-digit number to remember, while the second group was given a seven-digit number. Then they were told to walk down the hall, where they were presented with two different snack options: a slice of chocolate cake or a bowl of fruit salad.

Here's where the results get weird. The students with seven digits to remember were nearly twice as likely to choose the cake as students given two digits. The reason, according to Prof. Shiv, is that those extra numbers took up valuable space in the brain—they were a "cognitive load"—making it that much harder to resist a decadent dessert. In other words, willpower is so weak, and the prefrontal cortex is so overtaxed, that all it takes is five extra bits of information before the brain starts to give in to temptation.

Swedish blog tags: Vetenskap, Nyårslöften
Technorati tags: Science, Mind, Resolutions

Kim Peek died

I guess everybody found out today that megasavant Kim Peek died of a heart attack this past Saturday. Although he may have been mostly known for being the "original Rain Man", and from diverse TV documentaries, he should be remembered for how he managed the many adversities of his condition, with great help from his father Fran, and helped us to understand how the brain works.

Fellow savant Daniel Tammet says it best:

Kim was a remarkable human being, blessed with astonishing mental gifts; he also battled numerous handicaps throughout his life. At the same time, he was funny, provocative, and down-to-earth. I remember fondly how he regaled me (and the documentary’s film crew) with all manner of facts and jokes, tunes and anecdotes. When I interviewed his father Fran, he was unsurprisingly extremely proud of his son, and vividly described Kim’s history and current life, which included much travel across the States with the important message that difference needn’t be a disability, because everyone’s different.

Read the entire post at Daniel Tammet's blog.

Kim Peek's mind was truly remarkable. He had memorized thousands of books, reading the right page with the right eye and the left page with the left eye, and could recount innumerable facts and trivia from them. He also enjoyed impressing an audience by accurately calculating the weekday of their birth, or indeed of any of their future birthdays. The most striking anatomical feature of his brain was the complete lack of the major lines of communication between the two hemispheres, the corpus callosum and the anterior commissure.

You can read all about Kim Peek and watch several excerpts from his many media appearances on the website of Dr. Darold Treffert at the Wisconsin Medical Society. Dr. Treffert is the savant researcher with whom father and son Peek collaborated for many years.

Kim Peek was 58 years old.

Swedish blog tags: Vetenskap, Neurovetenskap, Kim Peek
Technorati tags: Science, Neuroscience, Kim Peek

'Why we believe in gods' lecture

From the Richard Dawkins YouTube channel: Psychologist Andy Thomson talks about why we believe in gods at the American Atheists 2009 convention. He talks briefly about the brain imaging study I wrote about in a previous post.



Of course he's an atheist speaking to a (I would assume) largely atheist audience and it comes through, but I think the main point, at least to me, is general enough to be appreciated and understood by everyone. At the very least he provides a hypothesis for how belief is generated in our brains, although he does focus too much on adaptations, and at the very most he demonstrates how unlikely gods are. There's plenty there to discuss.

Swedish blog tags: Neurovetenskap, Hjärnan, Religion, Ateism
Technorati tags: Neuroscience, Brain, Religion, Atheism

Religious belief in the brain

I've often wondered what's going on in the religious brain that is so different from what's going on in mine. How can religious people so determinedly "get it" while I just as determinedly don't. Turns out that, in a sense, not that much is different. Religious belief works through brain networks that have regular non-religious functions, suggesting that religion is nothing but a secondary effect of regular cognitive processes.

A study published in PNAS last week (ahead of print) set out to examine which psychological "dimensions" make up religious belief and how the brain processes them, largely through the use of functional magnetic resonance imaging, fMRI - a technique that allows researchers to get images of brain activity in awake test subjects performing different tasks. In this case the task was agreeing or disagreeing with statements such as "God is removed from the world", God is punishing", "God is forgiving", "A source of creation exists", "Religion provides moral guiding" and so on.

Some interesting conclusions:

The practice of religious belief involves the assessment of god's perceived involvement in the world and god's perceived emotion. So when we ponder god, we use the same brain networks that are used for understanding the intent of people around us, understanding their emotional state, predicting their actions and generating an appropriate emotional response to give back. This is a central mechanism behind our social interactions. This study demonstrates that we think of gods just as we think of anyone around us. There are no particular parts of the brain that are dedicated explicitly to understanding god, instead our brains try to "read" god just as we read the people we interact with.

It also seems like the reason some people adopt religious beliefs while other don't is largely emotional, with the effect being larger for those who are believers. When religious test subjects were asked to actively deny a series of religious statements they showed much larger involvement of brain networks involved in the communication between emotions and cognitive processes than non-religious test subjects. You can see these brain regions in the lower row of the figure below. This finding will be familiar to any non-believers who have discussed religion with believers. Their final arguments are often emotional instead of logical, they often claim to "just know" and their position is motivated by the negative emotional response of considering a world without god.


Ref: D. Kapogiannis et. al. (see reference below)

I'll take the opportunity to recommend the blog where I first found this study: Epiphenom. It's updated frequently with a lot of very nice information from studies on the neuroscience and psychology behind religious belief. You can read more there. But while the author of that blog states that this study doesn't do anything to prove that religious belief is a by-product of evolution, I see that it absolutely does. The authors even conclude with:

The evolution of these networks was likely driven by their primary roles in social cognition, language, and logical reasoning. Religious cognition likely emerged as a unique combination of these several evolutionarily important cognitive processes.

To me it's pretty clear that any supernatural belief is an "overshoot" of mental capacities that we use for other purposes, that we relate to supernatural entities just as we relate to those entities we interact with. Whether this is adaptive or not, whether it's been to our advantage or not, is another question altogether. I'm inclined to believe that given the complexity of the brain and the complexity of phenomena it can generate, it's unlikely that all of them, at any point in evolution, are the result of adaptation. The brain simply does too much. I'm open to the thought that cultural phenomena could have "abducted" some of our cognitive abilities more or less "by accident" to generate some of the more colorful phenomena of our cognition and behavior.

Kapogiannis, D., Barbey, A., Su, M., Zamboni, G., Krueger, F., & Grafman, J. (2009). Cognitive and neural foundations of religious belief Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0811717106

Swedish blog tags: Vetenskap, Biologi, Neurovetenskap, Hjärnan, Religion
Technorati tags: Science, Biology, Neuroscience, Brain, Religion

A little attention

To my amazement, I find that my entry on FOXP2 evolution gets a mention on the Public Library of Science (PLoS) blog in an entry highlighting bat research: At PLoS ONE we're batty about Bats. I didn't actually have that much to say about the article in question, Accelerated FoxP2 Evolution in Echolocating Bats, but thanks so much to PLoS for the wink anyway.

This is what little I wrote regarding FOXP2 in bats.

FOXP2 has diverged more in echolocating bats than any other group of vertebrates. This further implicates FOXP2 in sensorimotor coordination and vocal learning, which are requirements for echolocation. The same pattern could not be seen for echolocating whales, presumably because their echolocation is mediated through their foreheads and would not require sensorimotor coordination of their mouth and face.

I think the entries by Language Evolution and Neurophilosophy are a lot better, so if you're interested in the subject you should go and read those.

Swedish blog tags: Vetenskap, Biologi, Neurovetenskap, Språk
Technorati tags: Science, Biology, Neuroscience, Language, FOXP2

Brain anatomy and a re-post: Scientific image database and Descartes' brain

Today I had a human brain anatomy demonstration for the undergrad students in the neurobiology course that my group is in charge of. It wasn't a long time ago that I was an undergrad myself and as I remember, this demonstration was one of the best parts. To get to hold and study an actual human brain that once belonged to someone and contained that person's personality and thoughts, to see in an actual brain how well structured and organized the brain is... it's a great thing. Since it's my first time I was a bit insecure in the beginning but I think it went great and I got the impression that the students left with the same feeling I did when I took the course some two-odd years ago.

When I was preparing for the demonstration yesterday I got some images from the Wellcome-images database and I remembered that I had blogged about it some time ago. It's a really great resource and an excellent source of procrastination. Here's a re-post of that:

>>Re-post from July 10, 2007.


Ref: Wellcome Images

The Wellcome Trust has launched a really great image database with all kinds of historical and scientific pictures. Just do a simple search on the word "brain" and bask in it's awesomeness. I was stuck for hours just looking up stuff. It's a really great resource. You can find it at http://images.wellcome.ac.uk/.

The old anatomical drawings fascinate me most of all. Like these ones; neuroanatomical drawings from the early 19th century, just astounding. History, science and art, all in one.

The above picture is one of my favorites. It's from Descartes' Treatise on Man and shows his peculiar view of the brain. He thought that the human being was two separate entities, body and soul, and that the two were connected through the pineal gland (the small bulbous-y thing in the center of the image, marked with an H). Descartes wanted to discuss the relationship between the body and the mind through sensory input and motoric output and involved the pineal gland as some sort of intermediary. He was wrong about that but the pineal gland does have a connection to the eye. It's involved in the control of biological rhythms and as such it receives light cues from the environment through the retina. This essential for "setting the clock", so to speak, but it happens through completely different pathways than vision. So that he included the eye so predominantly in the image makes it extra cool, even though he was completely out to lunch. A very nice image.

Swedish blog tags: Vetenskap, Neurovetenskap, Biologi, Hjärnan, Anatomi
Technorati tags: Science, Neuroscience, Biology, Brain, Anatomy

Brainbow

Ref: http://olympusbioscapes.com/gallery/2007/index.html

Beautiful isn't it? This award winning picture shows the brain stem of a transgenic mouse that has been modified using an exciting new technique called Brainbow. The mouse has been modified to express 4 different fluorescent proteins randomly in different neurons.

Much like pixels make many different colors possible on your screen, the different random combinations of green, red, cyan and orange fluorescent proteins make it possible to color individual neurons in nearly 100 different hues. You never know from the beginning which color every individual neuron is going to get, but with a choice of nearly 100 different possibilities chances are you're going to observe every individual neuron glow in a different hue, making it possible to chart complex neuronal pathways.


Ref: J. Livet et. al (see reference below)

The use of fluorescent proteins is an important technique to visualize for instance where different genes are being expressed. The gene that encodes the fluorescent protein, first found in jellyfish, can be introduced next to the gene of interest in the transgenic animal. Then both genes are going to be expressed at the same time and you can get a marker of what organ or what part of the brain your gene of interest is being expressed. It's simply going to glow in the dark.

Livet, J., Weissman, T.A., Kang, H., Draft, R.W., Lu, J., Bennis, R.A., Sanes, J.R., Lichtman, J.W. (2007). Transgenic strategies for combinatorial expression of fluorescent proteins in the nervous system. Nature, 450(7166), 56-62. DOI: 10.1038/nature06293

Swedish blog tags: Vetenskap, Neurovetenskap, Biologi, Hjärnan, Brainbow
Technorati tags: Science, Neuroscience, Biology, Brain, Brainbow