Can Your Brain Measure Time Without a Clock?
Minnesota scientists have identified a specific part of the brain that helps measure time internally.
--by Suzanne Boothby
While the passage of time may feel quite arbitrary—too quick on vacation and too long at the office—researchers have found that a small population of neurons in our brains are designed to track time. These neurons (cells that send and receive electrical signals) can actually measure time with a great deal of accuracy, according to their findings.
The study, published this week in PLOS Biology, involved creating a task for monkeys during which they could only rely on their internals sense of time and eliminating all external cues that could serve as clocks.
Scientists at the University of Minnesota’s Center for Magnetic Resonance Research (CMRR) identified a specific region of the brain called the lateral intraparietal area (LIP) that activates internal sensors to help keep time.
The Expert Take
Their findings are different from those of previous studies, in which researchers failed to eliminate external cues or the expectation of reward.
“In contrast to previous studies that observed a build-up of activity associated with the passage of time, we found that LIP activity decreased at a constant rate between timed movements,” lead researcher Geoffrey Ghose, Ph.D., associate professor of neuroscience at the University of Minnesota wrote in a press release. “Importantly, the animals’ timing varied after these neurons were more, or less, active. It’s as if the activity of these neurons was serving as an internal hourglass.”
Source and Method
Scientists trained monkeys in the study group to move their eyes back and forth, at regular time intervals, without rewards or external cues. They found that even without external sensory information, the monkeys were extraordinarily precise and consistent in their timed behaviors. Researchers mapped the activity of the monkeys' neurons as they performed the task.
The study suggests that the brain does not have a "central clock" to manage timing, but rather that each of the brain’s circuits responsible for different actions can independently produce timing signals. Future research could explore how these timing signals are related to practice and learning, and what might occur if the signals are altered.
A 2008 human study at UCLA examined our ability to quantify time from microseconds to daily circadian rhythms, and also suggested that we possess an internal timing mechanism.