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My lab:
lab.png The cliché scientist is often portrayed as the laborious worker slogging away days and nights in the lab. In contrast, the cliché for musicians or artists often comprises a bohemian lifestyle, full of parties, drugs and the occasional spurts of genius and frantic artistic expression. Reality, as always, is somewhere in-between. Artists need to work hard and laboriously to get something finished before the concert, recording or exhibition and scientists need to be creative and invest a lot of thought and effort into devising the new hypothesis or the clincher experiment. In his highly readable autobiography "Physics and Beyond" Werner Heisenberg of uncertainty-principle fame tells us that, when stuck with a complicated problem, he would have to leave the institute and spend time in nature, away from everything, waiting for the creative idea to solve the problem. In today's publish-or-perish scientific culture, such behavior is a young scientist's doom. Heisenberg received his Nobel Prize at the age of 31, an age where today's scientists barely get around towards their first or second postdoc and a tenured faculty position is still about a decade away, on average.

It's been known for a very long time that creativity requires a so-called 'relaxed field', meaning an absence of outside stressor distracting from the thought processes at hand. I've written before about neurobiological research uncovering the biological basis for this requirement. Today I listened to a podcast from Radio National on the "Powerful Biology of Stress", which reminded me of that post. In the podcast, Bruce McEwen, one of the researchers the host, Natasha Mitchell, interviewed, mentioned research of one of his graduate students, Connor Liston. Connor Liston had conducted a series of experiments in rats which showed that
when the animal, the rat, is challenged with a complex task in which it has to shift the meaning of cues that predict where a food reward is, if the task is difficult, having either a lesion of the prefrontal cortex which other people did, or chronic stress, reduces mental flexibility. Their ability to shift is not totally gone, it's just much slower and less efficient.
Confirming much previous work, chronic stress reduces mental flexibility in rats and lesion studies pointed towards the prefrontal cortex. Connor Liston found that in the prefrontal cortex, under chronic stress
these neurons are shrinking, the dendrites are shrinking and they're losing connections. So they are losing a very important input—it's a reversible process, if you stop the stress it will grow back.
Chronic stress leads to dendritic pruning in the medial prefrontal cortex, which probably accounts for the loss in flexibility. So far, this research is interesting, but still on the level of the rat model system. How would this research translate into humans under chronic stress? Just over one year ago, Connor Liston published a study in PNAS about chronic stress in medical students who were preparing for their board exams.
he used something called the perceived stress scale, which actually asks you questions about how much in control of your life you are in and what things are causing you to be stressed out. What he also did was to develop a human task which was very much like what he did with the rats, and they used functional brain imaging to define a circuit that was activated by this task. They could observe this circuit in these stressed students and they found that the more stressed out, the less efficient was the circuit, and they also showed an impairment on this behavioural task.
While dendritic pruning cannot easily be studied in live human beings, it is tempting to speculate that also in humans this process takes place in our prefrontal cortex under chronic stress and causes you to fail in behavioral tests which require mental flexibility.

This kind of research shows that not only were the old reports which connected creativity with what people at the time called 'a relaxed field' correct, we are now finding out what the neurobiological basis of this connection is. This research also demonstrates even more clearly how detrimental a stressful environment is for scientists: lacking the mental flexibility to think out of the box, to distance yourself from the problem at hand to maybe find the ingenious solution, stress postpones the progress of science. Forcing scientists into habits and grunt work, stress pushes science into dead ends and wasteful spending. Today, scientists finish their PhDs when they're just about to turn 30 and receive their first own grant in their 40s. During this decade, they live on short-term contracts and any failure to publish could mean the end of a life in science. For many 40-somethings, having been scientists for all their lives, never seen a company from the inside, a dry spell at any time in their career may mean the end to any middle-class life, with salaries being so low that no large savings would ever accrue. I'm not aware of any study investigating the reversibility of dendritic pruning after a decade of existential stress, but I'm willing to hazard a guess that a scientist's most formative years are not being used to their full potential by our current system and may even be detrimental for the final decades of a scientist's work. It is also conceivable that such existential stress incentivizes fraud and other misconduct in scientists who under normal circumstances would never be prone to such behavior.

Interesting for my own research is the aspect that the critical factor deciding what is considered stress in these neurobiological studies, was whether or not the rats or humans had any control over their circumstances (restraint in rats and the exams in humans). My own research focuses on how the brain learns to control its circumstances and how it detects whether it is in control or not. Maybe one day my own research will contribute to a better understanding of how to contstruct a professional work-environment that fosters science, instead of stifling it.

Liston, C., McEwen, B., & Casey, B. (2009). Psychosocial stress reversibly disrupts prefrontal processing and attentional control Proceedings of the National Academy of Sciences, 106 (3), 912-917 DOI: 10.1073/pnas.0807041106
Radley, J. et al. (2005). Repeated Stress Induces Dendritic Spine Loss in the Rat Medial Prefrontal Cortex Cerebral Cortex, 16 (3), 313-320 DOI: 10.1093/cercor/bhi104
Posted on Monday 15 March 2010 - 11:30:47 comment: 0

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