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.