Time-keeping brain neurons identified

STATE COLLEGE, Pa., Oct. 22 (UPI) -- U.S.-led researchers say they have, for the first time, identified groups of neurons in the primate brain that keep time with extreme precision.

The researchers from Penn State University, the Massachusetts Institute of Technology and Japan's Riken Brain Science Institute said their finding is an important step toward discovering how brain cells keep track of timing actions, such as speaking, driving a car or throwing a ball.

"This research is the first time that precise time-keeping activities have been identified in recordings of neuron activity," Penn State Assistant Professor Dezhe Jin said, noting the time-keeping neurons are located in two interconnected brain regions -- the prefrontal cortex and the striatum -- both of which are known to play critical roles in learning, movement and thought control.

"The key finding is that neurons in the prefrontal cortex and the striatum encode the time information associated with sensory cues," Jin said. "Visual cues, for example, elicit a variety of responses in a particular population of neurons. We found that the brain is able to tell the passage of time from the visual cues because different neurons are active at different times.

"Most remarkably, we found that there are neurons that are active at precise times after a particular visual cue, and these neurons act like clocks that mark time," he added.

The study is reported in the Proceedings of the National Academy of Sciences.