Antidepressants and neurogenesis / plasticity

It is relatively less well known that much of the anti-depressant effect of medications like Prozac may be due to them leading to better neurogenesis in the brain/ hippocampus. It is more well known that depression may itself be caused due to reduced neurogenesis. What is most well known is the scientifically unproved 'serotonin' theory of depression and how SSRIs work by increasing the level of serotonin in the brain.

Now a new research paper shows that Prozac has a non-specific effect on plasticity ion the brain and can even be used to treat Ambylopia, a defect of visual system, by rewiring the brain. Here is the abstract:

We investigated whether fluoxetine, a widely prescribed medication for treatment of depression, restores neuronal plasticity in the adult visual system of the rat. We found that chronic administration of fluoxetine reinstates ocular dominance plasticity in adulthood and promotes the recovery of visual functions in adult amblyopic animals, as tested electrophysiologically and behaviorally. These effects were accompanied by reduced intracortical inhibition and increased expression of brain-derived neurotrophic factor in the visual cortex. Cortical administration of diazepam prevented the effects induced by fluoxetine, indicating that the reduction of intracortical inhibition promotes visual cortical plasticity in the adult. Our results suggest a potential clinical application for fluoxetine in amblyopia as well as new mechanisms for the therapeutic effects of antidepressants and for the pathophysiology of mood disorders.

Now this brings me to an important conclusion. We have shown earlier that depression is associated with a bland sense of taste and a bland sense of smell. I have also heard of anecdotal evidence (including from readers of this blog) that depression leads to loss of fine sensation capabilities in other realms too including loss of an ability to discern pitch. Thus, to me it seems that the reason one has bland sensations in depressive states may have to do with reduced neurogeneisis and loss of neurons in the sensory areas. Anti-depressants also restore the sense acuity back, so apparently they are able to induce neurogenisis and plasticity in other barin regions than the hippocampus and their anti-depressant effects may largely be due to this factor. I had hypothesized earlier that depressed people should have diminished sense in other areas too - like that of vision and it will be interesting to see if data exists to support this view. Are there disorders similar to the 'lazy eye' that are more common in depressed people than in normal controls ; if so they would definitely be cured by prozac and one reason why people may be getting better due to medication may be because they can feel the world as vivid again. I theorize that while everything seems more vivid in mania, the reverse is true for depression and the underlying reason may be the anomalous neurogenesis. If so, there is hope for people who get their senses diminished as a result of depression- with an insight into how anti-depressants work - by improving neurogenisis and plasticity- we may be able to make better drugs that benefit them.

I'll be watching this anti-depressant as a general enhancer of plasticity theory very keenly in the future and would love any pointers to research on the same lines from my readers.

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The facebook persuasion methods

There is a  recent article  on BBC that covers The Psychology Of Facebook course of professor B J Fogg a persuasion psychologist from Stanford. This is a bold attempt to teach psychology of persuasion by taking a real world of Facebook and its viral growth as well as the growth of applications on Facebook.

He says: "When Facebook came along I was one of the developers at the
launch and what struck me was how there was this new form of
persuasion. This mass interpersonal persuasion."

Professor Fogg says the pivotal moment came when he watched an
application on the site go from "literally zero to more than a million
users in a week".

"Where on earth could you get a million customers in a week? That was
when I said 'I want to learn more about this' and I thought the best
way was to teach a class and look at how persuasion happens."

There is an interesting case study of why people upload their profile photos:

Today the focus is on the use of profile pictures, the photograph on the front page of every Facebook entry.

The discussion is lead by Psychology Senior Richard Barton, who
maintains Facebook's high strike rate in this area has to do with the
default picture it puts up if you don't post your own.

"Who wants a question mark in place of their face and what questions
does that raise about you? Like, why are you on Facebook? And so
basically Facebook sets up an environment where your friends do the
persuading to get you to post a picture."

This is interesting. Others before Facebook have tried various measures for persuading users to reveal their true identities. A case in point is the tongue-in-cheek 'anonymous coward' that is displayed as your user name on slashdot if you do not sign in and give your real user name. I don't know whether it was the question mark, or because I normally do not value anonymity, but I posted my photo on Facebook as soon as I joined.

BTW, for those of you who want to connect: here is my Facebook profile page and I'll love to get connected with my readers. Also in case someone is interested my twitter id is sandygautam and you can also follow me there.

 

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Art and Insanity: is there risk involved in artistic creation?

William Schultz has just posted a blog entry regarding how artistic creation may have an associated risk of suicide/ depression/ psychosis and how exploring the depths of one's psyche may lead one to the downward spiral that ends with taking one;s own life. He gives Sylvia Plath and Diane Arbus as examples and I agree with his basic premise that writers/ artists are especially vulnerable to extreme mental states as they try to explore the depths of human experience by imagining the extremes that are possible.

I ,myself, consider myself to have moderately good writing talent, and have found that when I write literature , be it poems or short stroies or novellas, the theme of the creation starts taking its hold. this is most apparent when for example I recently added a few sonnets to my epic-in-making The Fools Quest. The initial sonnets depict a person who is on a brink of new journey, somewhat facing an existential angst and in general questioning both his past and his future. now, though, I myself am very well adjusted and happy with my life as it is going, just creating in myself the protagonists mindset led to a state where I myself started feeling restless, unsatisfied and in general more eager for change and willing to rock the boat. This may seem anecdotal evidence, but there is good statistics showing prevalence of mental health disorders in artists in general and writers in particular.

I would now quote a bit from Schultz' post (italics mine):

What's going on here? It's more than a little uncanny. As Wendell Berry once said: "To go in the dark with a light is to know the light. To know the dark, go dark." Both Plath and Arbus knew the dark, but this knowing came at a massive price. The dark stayed dark. Forever. Some artists--not all--do not survive the hero's quest. Maybe, when the moment comes, they lack the requisite "ego strength" to re-compose after the decompensation that a certain category of art requires. Or else: once they achieve genius, the question becomes: Where do I go from here? Having reached the top of the mountain, there is nothing left but the descent, and the idea of descending is simply intolerable, ultimately depressing.

I don't know, whether my quest is a hero's quest or a fool's quest , but I definitely know that I have slowed down as I saw that the quest was affecting my mood. Hopefully, as the quest moves to more adventurous phases and away from the initial dilemmas , it would have more uplifting effects. Hopefully, I wont fall from the cliff like my Fool is planning to!

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Nature via Nurture : aggressiveness in Dorsophilia

As per a recent PNAS article , Dorsophilia have a gene called Cyp6a20 which is expressed more in the head when the flies are not socially isolated but have social experience. This increase in gene expression is correlated with a decrease in aggression. Thus, this gene codes for not only the genetic component of the inheritableness of aggressiveness in the Dorsophilia, but also the environmental effect of social stimulus on aggressiveness and how that environmental influence is itself dependent on genes. To make it clear, Dorsophilia that had this gene mutated showed a change in aggressiveness only for flies that were reared in social groups and had no effect when they were reared as socially isolated.

To me, this seems another case where nature and nurture do not necessarily have to work exclusively, but work in concord to give observable phenotypes. It is interesting to note that this same gene is also expressed in olfactory sensilla and this suggest that aggressiveness - socialization effect may be mediated by pheromone effects.

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Psychology Today blogs

I had blogged earlier regarding the Magical Thinking article in Psychology Today. It seems that Psychology today also has a blog by its editors called Brainstorm and in it there are a couple of blogs regarding the same article by the same author and readers may find them wroth checking out.

While we are at it, Psychology Today also has many other blogs of note there and authors include people like Satoshi Kanazawa, Peter Crammer , William Todd Schultz etc. So have a look!

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Genocide and Mortality Saliance

There is an interesting article at We're Only Human, that argues that being exposed to people who have a different philosophy or world-view form our own can lead to feelings of Mortality Salience or awareness of our own Mortality. We all know that humans are aware of their own mortality and yet, can go about their daily business, nonchalantly , as they find solace in their cultural world-view , of being part of a religion or group with shared philosophy/ world-view. This is the basis for the Terror Management theory.

Now the article further argues, that if we witness the annihilation of people whose philisophy / world-view is different from ours , and who by their mere presence have induced a Mortality salience in us; then we can , by witnessing their annihilation, overcome the terror of death and manage its impact. thus, our propensity for genocide. all this is not based on mere speculation, but there is experimental evidence, that thinking about people with a different philosophy does lead to thoughts of personal death and fear of ones mortality; that witnessing or being told about the death of members holding that alternate philosophical view does lead to proper management of that terror and thus theoretically the rationale of hidden reasons behind genocide.

All that is fine; but the research was conducted using a religious paradigm. what if the other group exposed to was that of atheists; or a capitalist group was pitted against communist ideologies; would the results still hold. Historically, there has been much bloodshed between religious factions, and memories of that may color the results as people realistically feel threatened due to the checkered history of mankind. If we can be user that the terror is due to mortality salience induced by exposure to different philosophy ; and not just due to memories flooding back; than the results could have a greater implication.

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Brain Feminization of males with schizophrenia?

I don't really know what to make of Mendrek's results as discussed in this article that claim to have discovered “masculinization” of females and “feminization” of males with schizophrenia (at least at the neuroanatomical level).

The study, that used emotive film clips and fMRI to find the pattern of activation on watching emotional stimulation in a schizophrenic population, did not have any normal controls. Thus, while the fact that their results showed greater activation in Males as compared to females may be true, they do not tell us how this is related to the activation in normal population? Are schizophrenic in general more emotional than baseline normal people or less emotional is not clear. It is presumed that the baseline normal activity falls midway from what was observed in males and females and thus males more feminized while females more masculanized.


I also do not know how to integrate this finding with my framework that sees Autism and Schizophrenia/ psychosis as opposite ends of spectrum. If we juts limit our discussion to Males, then everything seems fine. Autism is the 'extreme male brain' theory while schizophrenia in males is 'feminization' of Masculine brain. but what when we extend the ambit to cover females. should one posit that schizophrenia is characterized by movement away from gender based brain development; while Autism is characterized by movement towards gender specific brain development. In this case one would conclude that female autistics were an extreme female brain. I don't like this argument as there seems scarce evidence for that. I would instead argue that even females in Schizophrenia are more feminized and this may have to do with the imprinting genes that we have discussed earlier. If the evidence was there that both males and females are more feminized in schizophrenia, life would be simple. Let me know what you think in comments and of any evidence you may be aware of.

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A Schizophrenia quiz

I always believe that questions and quizzes are an integral part of learning and retaining new information. So from now on , I'll be regularly posting some quiz questions on a particular topic on the left had side bar of The Mouse Trap. You have to click on the 'next question' button to get at the first question. Then you have to click the buttons on the top of each alternative for the correct answer. The tool keeps track of your number of tries and correct responses and also provides explanations for the correct answers.

I intend to use this tool extensively in the future. do let me know, whether you find the tool useful and would love to see similar quizzes hosted on the Mouse Trap.

I know that many of you read the Mouse trap as part of an RSS blog reader. However, I would request you to visit The Mouse Trap and give this a shot.

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