How the brain makes time experience – study


Time, that frustration limits our resources and ruler-building lives, Still confuses neuroscientists. What is particularly surprising is that while you are waiting in line, the time can last at a blistering pace, but during enjoyable activities, a rush of hours in minutes is seen, such as going to a concert. .

In other words: Why does time fly when you are having fun?

In a recent study, researchers went one step closer to answering this perplexing question. By studying people’s brain activity during tasks where time is manipulated, scientists found that there are Time sensitive neurons That fire in response 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 with understanding space and motion.

When exposed to similar long-term stimuli, these time-sensitive neurons may deteriorate. Meanwhile, other neurons continue to function normally, creating an imbalance that eventually stops the perception of time.

Based on these findings, if someone is shown the same 50-second video, for example, they may have trouble guessing the subsequent clip, even if it is too long or short.

These findings were published on Monday Journal of Neuroscience.

Masamichi Hayashi is the study’s co-author. He is a researcher affiliated with the Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka University and University of California, Berkeley. Hayashi has long investigated the neural basis of time.

Hayashi insisted In the shlokas This discovery is “only the first step” towards fully understanding the nervous system of subjective time experiences. Nevertheless, they say that there are some practical avenues.

One message he can deliver is, he says, “Don’t trust your sense of time, especially when you were exposed to stimuli with a constant interval of time, which can lead to nervous fatigue of time-sensitive neurons in your brain. ”

To know how the brain experiences time, Hayashi and his team used functional magnetic resonance imaging (fMRI) to measure brain activity, as time compared to 18 healthy adults who performed the task. This technique measures small changes in blood flow that occur with brain activity.

“While humans have sensory organs to experience the pitch of vision light or sounds, there is no specific organ for the perception of time,” Hayashi explains. “This means, our understanding of time is probably the product of our brain activity.”

In the time comparison task, participants saw a gray circle on a screen for a set amount of time, 30 times in a row. This was considered the adaptation period. Participants estimated how long it lasted, “the duration of the adapter”. After this initial adaptation period, the group was shown a test stimulus (either a gray cross on the screen or a sample of white noise) and re-estimated time.

This optimization process allowed researchers to manipulate the perceived duration while keeping the physical duration constant.

How does the brain experience time?

When the adapter duration (gray circle exposure time) was longer, participants underestimated the time of the test stimulus; If it was shorter, they reduced the test stimulus time.

When the adapter and test stimuli were similar in length, activity in the SMG decreased, suggesting that the individual’s neurons were fatigued. The distortion of people’s time was related to how little the activity in their SMG decreased.

More tired neurons Seemed, The worst people were guessing the time.

A view of brain activity in the supramarginal gyrus (SMG), which researchers say is the neural location of subjective time.Journal of Neuroscience

“Our finding suggested that time-sensitive neurons in the parietal cortex become tired after exposure to repetitive presentation of a specific time interval and result in distortion of time perception,” Hayashi explains.

In particular, the results suggest that activity in the right SMG reflects humans’ subjective experience of time.

Interestingly, these time-sensitive neurons function in the same way as other neurons, which underline how humans experience space.

Hayashi explains, “It is already known that basic spatial characteristics such as the orientation of a bar or its movement are represented by a population of neurons that are sensitive to specific orientation and motion-direction.”

“Surprisingly, despite the fundamental difference between how we view light and time, we found that time-sensitive cells are likely to be encoded, and this activity is linked to how humans perceive time. Understand. ”

One day, researchers may be able to Manipulate the subjective meanings of the people of time By stimulating these time-sensitive neurons. By then, people will have to find other ways to spend time in the waiting room and boring work presentations and hope their neurons don’t get too tired.

abstract: The period assumption in the subsond range is designed to be mediated by the population response of period-sensitive units, each tuned to a preferred period. One line of support for this hypothesis is that neuroimaging studies suggest that cortical regions, such as parietal cortex, exhibit period tuning. If this representation is based on the physical duration or subjective duration of sensory input, it is unclear whether a question that matters is that our perception of the passage of time is often not conceptual, but rather biased by various contextual factors. Here we used fMRI to examine the neural correlates of subjective time perception in human participants. To manipulate perceived duration while keeping the physical duration constant, we employed an optimization method in which, before recognizing the duration of a test stimulus, participants were exposed to a train of adapting stimuli of a certain duration. In practice, this process produced a clear negative result: a shorter adapter biased participant for over-estimating stimuli and a longer optimally biased participant for underestimating stimuli. Period tuning modulation, manifested as an stuck BOLD response to stimuli similar to the period of the adapter, was observed only in the parietal lobe and the supramarginal gyrus (SMG) to the right of the middle occipital cirrus. Across individuals, the subsequent magnitude of behavior was positively correlated with the magnitude of duration tuning modulation in SMG. These results indicate that period-tuned neural populations in the right SMG reflect the subjective experience of time.