Brain’s minute observations

Using the analogy of the ripples, Buonomano says the brain measures time by processing the event itself: The farther the ripples travel in response to the rock, the more time has passed.

In the brain, the researchers discovered, telling time occurs at the level of the neurons as it processes an event. Each step in the reaction leaves a footprint in the sand, and time is measured as a sum of the footprints.

“That’s how the brain tells time,” said Buonomano, an associate professor of neurobiology and psychiatry at UCLA’s David Geffen School of Medicine. The study was in the journal Neuron. “Many complex behaviours — from talking to understanding what someone is saying to making music — rely on the brain’s intricate ability to tell time,” he said.

There are many implications for the fundamental finding, scientists say.

“This is an elegant demonstration of how the brain can locally encode the durations of brief sensory events without engaging a centrally located clock that controls more global timing functions,” said Warren Meck, a professor of psychology and neuroscience at Duke University in Durham, North Carolina, who is not part of the study. “It has important implications for our everyday perception of the temporal relationships among all of the sights and sounds that we process — including our ability to play the violin or swing a baseball bat. It’s a beautiful paper and quite timely.”

To prove their timing theory, they used a computer to simulate a network of brain cells responding to a sensory stimuli and watched as the network kept track of the timing of this event. Then, they took the model to human volunteers and asked them to judge the interval between two or three tones. Again, the brain revealed that it could tell time by recording the events that had taken place. If a random tone was introduced into the experience, the volunteers’ sense of timing was thrown off.

The scientists say that this model explains the processing of events that occur in less than a second. This fast processing is what humans use to understand speech and appreciate music. Buonomano said these mechanisms are wired throughout the brain so that people can immediately experience the events of the world around them. He said it may also provide clues to understanding abnormal linguistic processing that occurs in people with dyslexia.

He added that there may be other brain systems at play when someone is trying to figure out how long someone has waited in a line or how long it takes for the coffee maker to deliver the goods.

Buonomano worked with postdoctoral fellow Uma Karmarkar of the University of California, Berkeley. The study was funded by the National Institute of Mental Health.

—Jamie Talan / Newsday