New study pinpoints how the brain ’s inner clock measures seconds

FINDINGSUCLA neuroscientistsstudying how the brain measures time in secondsintroduced mice to two different scents. The mice learned that one odor predicted the arrival of a sweet liquid reward after three seconds, while the other predicted the reward after six seconds.The mice started licking the spout earlier in anticipation of the reward after they sniffed the first scent than when they smelled the second.While the mice responded to the two stimuli, researchers observed activity intwo regions of their brains: the striatum and the premotor cortex,which provides input to the striatum. They found that while both regions encoded time, consistent with the notion that the brain has multiple clocks, the pattern in the striatum was closer to a sequence of falling dominoes — a pattern referred to as a neural sequence —than werethe patterns in a motor area.BACKGROUNDTracking the passage of time to the second is critical for motor control, learning and cognition, including the ability to anticipate future events. While the brain depends on its circadian clock to measure hours and days, the circadian clock does not have a second hand.Instead, the brain measures seconds through changing patterns of cellular activity. Much like a line of falling dominoes, each neuron activates the next, and time is marked by the neuron that is currently active. By analogy, if a sequence of falling dominoes takes 10 seconds from start to finish, one can deduce that 5 seconds has elapsed when the mid...
Source: UCLA Newsroom: Health Sciences - Category: Universities & Medical Training Source Type: news