Thinking Fast and Slow about Thirst

Out of all motivational states, thirst should have been a simple one to understand. One feels thirsty when one is dehydrated, which can be detected from blood volume and osmolarity. Drinking water hydrates one’s body and quenches thirst. This is a homeostatic model. Intuitive, right? Well, the strange thing about thirst is that it is quenched within seconds to minutes after drinking water, which is too fast for any changes in the blood to happen. This is as if the brain gets hydrated before the body, which makes little sense since there is no specialized canal that passes water from mouth to brain (thank goodness). On the other hand, the buildup of the thirst drive is usually rather slow, meaning that thirst state can change on both a fast and slow time scale. How does it work?

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Consider the Fun

Scientists are often portrayed in pop-culture as pedantic types, with personalities as stiff as their starched white lab coats. While they may have a pressing work ethic and incessant care for detail, their work is creative by nature. Scientists must create knowledge by designing and building experiments. In this way, a scientist is closer to a starving artist than to an automaton.

A scientific project might be spawned from reading a paper and finding an unanswered question, or just observing a phenomenon and wondering how it happens. This stage is quite exciting – you imagine yourself doing experiments that will answer your question (or you imagine collecting data using some brand-new technique, and the results would be unlike anything anyone’s ever observed). The prospect of discovering something new is as thrilling as falling in love. Read the full post »

True Beauty

“Beauty is truth, truth beauty,” – that is all
Ye know on earth, and all ye need to know.
– John Keats in ‘Ode on a Grecian Urn’

The scientific field prides itself in its objectivity. Truth is found by a search free of personal biases, personal commitments or emotional involvements. Still, a great many scientists have said beauty guided their way. For example, physicist Paul Dirac stated: “It is more important to have beauty in one’s equations than to have them fit the experiment”.

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As simple as random can be

A few weeks ago I was having a discussion about mathematical models for the prediction of the movements of the stock market. The question was whether there was any use to developing complex algorithms trying to predict these fluctuations. My friend (an economist) argued that while he admits the market value isn’t truly random, incorporating random variables may be the best model we have for it. It turns out that many mathematicians (and quants, economists who analyze market fluctuations using algorithms) have been using “random” models for their predictions. These range from sequences randomly drawn from log-normal distributions, to chaotic systems that may allow for the prediction of market crashes and other rare large movements. I was fascinated by the idea of randomness as a model for complex systems. It seemed particularly interesting to explore this in the context of biological processes, especially when the laws of thermodynamics have described that all physical phenomena drift towards the chaotic state of maximum entropy. Could randomness be a model for circuit wiring and function in the brain?


The Drosophila mushroom body, shown in the MB010B-GAL4 line. Courtesy of Katrin Vogt.

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Keeping your head cool

During these hot summer days, lying in the shadow puffing and sweating, my arms and legs pulling down like bags of sand, it is sometimes difficult to believe that my brain is still functioning fine. How do we manage to keep our head cool, even on hot days like these?

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The deciding brain and the effects of stress

meadow-680607_1920We make decisions every day. Decision-making is a way by which we exert control over our behavior, mood and even the course of our lives. One key element in decision-making is self-control. This is often seen when we have to make that extremely difficult decision between another double cheeseburger and a healthier salad. While that may seem difficult enough on its own, many decisions, such as having to choose which graduate program to join or which answer to circle on an exam, come with substantial amounts of stress. This stress can guide or compromise the decisions we make. So, how do stress and self-control come together during decision-making? What is the neurobiological basis underlying this convergence?

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The touch of a fly

Our sense of touch has an innate connection with our emotions. Gentle touches are soothing for not only us but also other animals. For example, classic experiments by psychologist Harry Harlow in the 1950s found that an infant monkey raised with two robots, one providing food and the other wearing soft cloth, spends more time cuddling with the cloth robot1. When scared, the infant monkey also goes to the cloth robot for protection. Clearly, there is a special pathway that guides touch sensation to the depths of animal instincts. Working out this pathway requires knowledge about the neural circuitry processing touch sensation.

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The secret life of our brains

A peek into the unconscious brain under anesthesia

In our everyday lives we are aware of ourselves, our behavior, and the sensory perception of our environment. This awareness during awake states is known as consciousness. As much as it is central to our brain activity, it has also been one of the greater mysteries of neuroscience. In our lifetimes we all experience changes in our state of consciousness, particularly in the alternation between sleep and wake states. We may also experience changes in consciousness state when fainting, during an epileptic seizure, and through the effects of psychoactive drugs. What is happening in our brains when our conscious selves are not present?


Morton’s ether inhaler, as used in one of the first successful demonstrations of general anaesthesia in October 1846. (6)

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Animal Welfare in Research

I recently had the opportunity to write a post for Nautilus on a subject that is dear to me – the use of crows and other intelligent members of the corvid family for neuroscience research. Corvid intelligence has been noticed by humans for millennia, and more recently by ethologists and psychologists. The fascinating thing about these animals is that like all birds, they do not have a neocortex – the part of the mammalian brain that has countless times been implicated in intelligence. Now, there is just one lab in the world – Andreas Nieder at the University of Tübingen –  that has started peering into the brains of these fascinating creatures to try to understand how crows’ cortex-less brains enable them to perform amazing cognitive feats. You can read the full story on Nautilus.

The post received moderate praise (thanks, mom!), but some of the comments on Nautilus struck me because they focused not on the ideas or experiments I proposed, but on the treatment of animals in research. Ricky, for example, wrote:  Read the full post »

Sharing while caring

Today, let’s throwback to the multiple comparisons problem and relate it to something new: Open Science.

Gold Diggers in Australia (Edwin Stocqueler, 1855)
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