How the brain bends our sense of time

brain opener free
Credit: Tang Yau Hoong

Time in the brain doesn’t follow the steady ticking of the world’s most precise clocks. Instead, it seems to fly by at one moment and practically stand still at others. This distorted sense of time may be caused, in part, by brain cells getting tired, according to a new study.

When the brain has been exposed to the same exact time interval too many times, neurons or brain cells get overstimulated and fire less often, the study finds. However, our perception of time is complicated, and many other factors may also explain why time moves slowly sometimes and quickly at others.

We have only very recently begun to understand how our brains perceive time. It was only in 2015, that researchers found the first evidence of neurons whose activity fluctuates with our perception of time. But it wasn’t clear if these neurons, found in a small brain region called the supramarginal gyrus (SMG), were keeping accurate time for the brain, or creating a subjective experience of time.

In the new study, the researchers used a “time illusion” on 18 healthy volunteers to figure it out. They hooked participants up to a functional magnetic resonance imaging (fMRI) machine that measures brain activity by detecting changes in blood flow.

The volunteers then went through an “adaptation” period, in which they were shown a grey circle on a black background for either 250 milliseconds or 750 milliseconds, 30 times in a row.

After this, the participants were shown another circle for a set period of time as a “test stimulus.” They were then told to listen to white noise for a certain amount of time and asked if the test stimulus was longer or shorter than the white noise. (They used white noise as a reference because an auditory stimulus isn’t affected by the visual adaptation but the visual test stimulus is.)

The researchers found that if the test stimulus was similar in length to the adaptation stimulus in duration, activity in the supramarginal gyrus decreased. In other words, neurons in that region fired less than when they were first exposed to the grey circle.

Follow the latest news and policy debates on agricultural biotech and biomedicine? Subscribe to our newsletter.
Related article:  Here's why so many of us are spooked by artificial intelligence?

The idea is that this repetition “tire[d] out neurons,” that are sensitive to that time duration, said lead author Masamichi Hayashi, a cognitive neuroscientist at the Center for Information and Neural Networks at the National Institute of Information and Communications Technology in Japan. But “other neurons that are sensitive to other durations [were] still active.”

This difference in activity level distorted the participants’ perception of time, he told Live Science in an email. If exposed to a stimulus longer than the duration the brain was adapted to, the participant overestimated time and if exposed to a shorter stimulus, the participant underestimated time.

This can distort our sense of time in the real world. For example, an audience at a piano concert may adapt to a musical tempo. “Your audience may feel your musical tempo subjectively slower than it actually is after being exposed to a music with a faster tempo, even if you are playing the music at the correct tempo,” Hayashi said.

But “we cannot say at this point that neuron fatigue ’caused’ skewed time perception because our study only showed a correlation between neuron fatigue … and distortion of subjective time,” he said. “Our next step is to examine the causal relationship.”

It’s also possible that there are multiple mechanisms at work in the brain to create our single perception of time, he said. For example, our perception of time may be intimately related to our expectations, may be due to chemicals in the brain or even the speed at which brain cells activate one another and form a network when performing an activity, according to a previous Live Science report. “Addressing this question would be an important direction for future research,” Hayashi said.

The findings were published Sept. 14 in the journal JNeurosci.

Yasemin is a staff writer at Live Science, writing about biology and neuroscience, among other science topics. Yasemin has a biomedical engineering bachelors from the University of Connecticut and a science communication graduate certificate from the University of California, Santa Cruz. When she’s not writing, she’s probably taking photos or sitting upside-down on her couch thinking about thinking and wondering if anyone else is thinking about thinking at the exact same time. Find Yasemin on Twitter @yasemin_sap

A version of this article was originally posted at Live Science and has been reposted here with permission. Live Science can be found on Twitter @LiveScience

Outbreak
Outbreak Daily Digest
Biotech Facts & Fallacies
Talking Biotech
Genetics Unzipped
can you boost your immune system to prevent coronavirus spread x

Video: How to boost your immune system to guard against COVID and other illnesses

Scientists have recently developed ways to measure your immune age. Fortunately, it turns out your immune age can go down ...
mag insects image superjumbo v

Disaster interrupted: Which farming system better preserves insect populations: Organic or conventional?

A three-year run of fragmentary Armageddon-like studies had primed the journalism pumps and settled the media framing about the future ...
dead bee desolate city

Are we facing an ‘Insect Apocalypse’ caused by ‘intensive, industrial’ farming and agricultural chemicals? The media say yes; Science says ‘no’

The media call it the “Insect Apocalypse”. In the past three years, the phrase has become an accepted truth of ...
globalmethanebudget globalcarbonproject cropped x

Infographic: Cows cause climate change? Agriculture scientist says ‘belching bovines’ get too much blame

A recent interview by Caroline Stocks, a UK journalist who writes about food, agriculture and the environment, of air quality ...
organic hillside sweet corn x

Organic v conventional using GMOs: Which is the more sustainable farming?

Many consumers spend more for organic food to avoid genetically modified products in part because they believe that “industrial agriculture” ...
benjamin franklin x

Are most GMO safety studies funded by industry?

The assertion that biotech companies do the research and the government just signs off on it is false ...
gmo corn field x

Do GMO Bt (insect-resistant) crops pose a threat to human health or the environment?

Bt is a bacterium found organically in the soil. It is extremely effective in repelling or killing target insects but ...
favicon

Environmental Working Group: EWG challenges safety of GMOs, food pesticide residues

Known by some as the "Environmental Worrying Group," EWG lobbies for tighter GMO legislation and famously puts out annual "dirty dozen" list of fruits and ...
m hansen

Michael Hansen: Architect of Consumers Union ongoing anti-GMO campaign

Michael K. Hansen (born 1956) is thought by critics to be the prime mover behind the ongoing campaign against agricultural biotechnology at Consumer Reports. He is an ...
News on human & agricultural genetics and biotechnology delivered to your inbox.
Optional. Mail on special occasions.
Send this to a friend