Read more: 鈥�Mind maths: Five laws that rule the brain鈥�
As your mind flits from thought to thought, it may seem as if dozens of sensations and ideas are constantly fighting for your attention. In fact, that鈥檚 surprisingly close to the mark; the way different neural networks compete for dominance echoes the battle for survival between a predator species and its prey, and the result may be your wandering mind.
at the University of California in San Diego and Gilles Laurent at the California Institute of Technology in Pasadena were the first to notice this strange dynamic. They were studying the neuronal activity in the antennal lobe 鈥� the insect equivalent of the olfactory bulb in the mammalian brain 鈥� as locusts experienced different odours. Rabinovich expected the activity to flatline when they got used to each smell, but he was wrong. 鈥淓ven when the scent stimulus was constant, the activity of the principal neurons in the antennal lobe changed with time,鈥� he says.
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Looking closely, Rabinovich noticed that the pattern of activity was not random, but similar to the form described by mathematicians Alfred Lotka and Vito Volterra in the early 20th century. The Lotka-Volterra equations, also known as predator-prey equations, are a key ecological tool for predicting fluctuations in populations of interacting species. A predator near-exhausts its supply of prey, and so starves while its prey recovers, and the cycle starts again.
Rabinovich dubs such perpetual fights 鈥渨innerless competitions鈥� and he says they occur in the brain as well. Here, though, the fight is not between just two competitors, but between multitudes of cognitive patterns. None ever manages to gain more than a fleeting supremacy, which Rabinovich thinks might explain the familiar experience of the wandering mind. 鈥淲e can all recognise that thinking is a process,鈥� he says. 鈥淵ou are always shifting your attention, step-by-step, from one thought to another through these temporary stable states.鈥�
鈥淭he competing activity between brain regions resembles the perpetual fight between predator and prey鈥�
People with psychiatric conditions might benefit from the work. In the past, conditions like attention-deficit hyperactivity disorder were studied by looking at the quick snapshots of neural activity. But Rabinovich鈥檚 work gives neuroscientists a tool to make sense of the brain鈥檚 responses as they evolve with time, potentially explaining why the attention drifts in unusual ways. Working with Alexander Bystritsky at the University of California in Los Angeles, Rabinovich has already shown that his equations can accurately describe the neuronal activity associated with both ADHD and obsessive compulsive disorder (). 鈥淭hey are very convenient for diagnosing the disorders,鈥� he says.
鈥�170,000 kilometres of nerve fibres鈥�
This article appeared in print under the headline 鈥淧reying on your mind鈥�
