October 9, 2015

How the brain keeps time

Image: MIT News

Study reveals neuron-firing patterns that underlie time measurement.

(October 9, 2015)  Keeping track of time is critical for many tasks, such as playing the piano, swinging a tennis racket, or holding a conversation. Neuroscientists at MIT and Columbia University have now figured out how neurons in one part of the brain measure time intervals and accurately reproduce them.

The researchers found the lateral intraparietal cortex (LIP), which plays a role in sensorimotor function, represents elapsed time, as animals measure and then reproduce a time interval. They also demonstrated how the firing patterns of population of neurons in the LIP could coordinate sensory and motor aspects of timing.

LIP is likely just one node in a circuit that measures time, says Mehrdad Jazayeri, the lead author of a paper describing the work in the Oct. 8 issue of Current Biology.

“I would not conclude that the parietal cortex is the timer,” says Jazayeri, an assistant professor of brain and cognitive sciences at MIT and a member of the McGovern Institute for Brain Research. “What we are doing is discovering computational principles that explain how neurons’ firing rates evolve with time, and how that relates to the animals’ behavior in single trials. We can explain mathematically what’s going on.”

The paper’s senior author is Michael Shadlen, a professor of neuroscience and member of the Mortimer B. Zuckerman Mind Brain Behavior Institute at Columbia University.

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