How the Brain Produces Time Experiences — Research

Time, its frustrating resources and our dominant structure life, Still confusing neuroscientists. Especially confusing is during fun activities such as going to concerts, even though it seems that you can keep track of time at the glacier’s pace when you’re doing something like waiting in line. That’s why time seems to be in a hurry in a few minutes.

That is why Time fly When you are having fun?

recently Investigation, Researchers are one step closer to answering this puzzled question. By people’s research Brain activity While working to manipulate time, scientists Time-sensitive neurons Fires according to a specific length of time. These time-oriented neurons are located in the supramarginal gyrus (SMG), which is part of the right parietal cortex, which is also involved in spatial and motor perception.

When exposed to repeated stimuli that last for the same amount of time, these time-sensitive neurons can wear out. During that time, other neurons continue to operate normally, eventually creating an imbalance that distorts the perception of time.

Based on these findings, for example, if the same 5-second video is viewed 50 times, it can be difficult to estimate whether the subsequent clip is very long or short.

The results of these findings were announced on Monday Journal of neuroscience.

Masamichi Hayashi Co-author of the study. He is a researcher at the Information and Neural Network Center, National Institute of Information and Communication Technology, Osaka University, and the University of California, Berkeley. Hayashi has long studied the neural basis of time.

Hayashi emphasizes Reverse This finding is “only the first step” to a complete understanding of the neural mechanisms of subjective temporal experience. Still, he says, there are some practical points.

One message he can give is, “Don’t trust your sense of time, especially when exposed to stimuli at regular intervals that can lead to nerve fatigue of time-sensitive neurons in the brain. Especially after that. “

To clarify how the brain produces the experience of time Hayashi and his team used functional magnetic resonance imaging (fMRI) to measure the brain activity of 18 healthy adults engaged in a time comparison task. This technology measures small changes in blood flow that accompany brain activity.

“Human has sensory organs designed to perceive the light and pitch of vision, but no specific organ to perceive time,” explains Hayashi. “That is, our sense of time is probably the product of our brain activity.”

In the time comparison task, participants displayed a gray circle on the screen 30 times in a row for a period of time. This was considered an adaptation period. Participants then estimated how long it would last and showed the “adapter duration”. After this initial adaptation period, the group displayed a test stimulus (a gray cross or white noise sample on the screen) and the time was estimated.

This adaptation procedure allowed researchers to manipulate the perceived duration while maintaining a constant physical duration.

How does the brain perceive time?

Participants underestimated the duration of the test stimulus if the adapter had a long duration (gray circle exposure time). If it was short, they overestimated the time of the test stimulus.

Similar lengths of adapters and test stimuli indicate reduced SMG activity, suggesting that the person’s neurons are fatigued. People’s time distortions correlated with how much SMG activity diminished.

of More tired neurons Looked like The worst person was estimating the time..

“Our findings suggest that time-sensitive neurons in the parietal cortex become fatigued after being exposed to repetitive presentations at specific time intervals, which results in distortion of time perception,” Hayashi said. I will explain.

Specifically, this result suggests that proper SMG activity reflects the subjective experience of human time.

Interestingly, these time-sensitive neurons behave like other neurons that support the way humans subjectively experience space.

“It is already known that basic spatial features such as bar orientation and its movement are represented by a population of neurons that are sensitive to a particular orientation and direction of movement,” explains Hayashi.

“Surprisingly, despite the fundamental differences in the way light and time are perceived, time is likely to be coded by time-sensitive cells, whose activity is human time. It turns out to be related to the way we perceive. “

One day, a researcher Manipulate a person’s subjective sense of time By stimulating these time-sensitive neurons. Until then, you’ll need to find other ways to avoid spending time in the waiting room, giving boring work presentations, or getting your neurons too tired.

Overview: The perception of duration in the sub-second range is hypothesized to be mediated by a population response of duration-sensitive units, each adjusted to a favorable duration. One line supporting this hypothesis comes from neuroimaging studies that show that cortical areas such as the parietal cortex exhibit duration regulation. It is not clear whether this expression is based on the physical duration of sensory input or the subjective duration. It is important to consider that our perception of the passage of time is often impractical and biased by a variety of contextual factors. Here, fMRI was used to examine the neural correlation of subjective time perception of human participants. In order to manipulate the perceptual duration while keeping the physical duration constant, we adopted an adaptation method in which participants were exposed to a train to adapt a fixed duration stimulus before determining the duration of the test stimulus. did. Behaviorally, this procedure resulted in significant negative sequelae: short adapters biased participants to judge stimuli longer, longer adapters biased participants to judge stimuli shorter. I put it on. Duration-adjusted modulation manifested as a attenuated BOLD response to stimuli of the same duration as the adapter and was only observed in the bilateral parietal lobe and the right supramarginal gyrus (SMG) of the mid-occipital gyrus. Among individuals, the magnitude of behavioral sequelae was positively correlated with the magnitude of duration-adjusted modulation in the SMG. These results indicate that the duration-adjusted neural population of the right SMG reflects the subjective experience of time.