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It looks as if researchers have unlocked a pathway to time travel — in our brains, at least. 

Scientists have identified the neural pathways in the brain that allow us to recall memories and replay them in the correct sequence. 

This is a monumental step forward in potential treatments for people with memory problems!

A new study, led by researchers at the Brain and Cognition Research Center (CerCo) at the French National Center for Scientific Research says the pathways in the hippocampus, a complex structure embedded deep into the temporal lobe, enables humans to effectively time travel through life memories.

Lead researcher Leila Reddy, a neuroscientist, said, “The hippocampus is important for judging the temporal order of events (among other things), and damage to the hippocampus can result in an impairment of memory for temporal order (for example, remembering the order of a list of items). It’s therefore important to understand how temporal information is represented in the brain, so as to be able to design interventions or treatments to reduce these deficits in memory.”

The team of neuroscientists found these neurons, or “time cells,” fire during specific moments and may contribute to memory by encoding information about the time and order of events.

Researchers said they could decode different moments in time-based on the activity of the entire group of neurons while monitoring brain activity in an experiment. 

The experiment monitored brain activity in each human participant with epilepsy while they looked at images. The volunteers had electrodes implanted in their brains before the experiment, which allowed the team to record signal neurons firing. Then, participants viewed and memorized a sequence of five to seven images that included pictures of flowers, a bird, and former US President Barak Obama. At random intervals, the participants were quizzed on the next image in the sequence before it resumed.

“These patients have severe, drug-resistant epilepsy and are awaiting surgery,” Reddy explained, “Part of the pre-surgical procedure involves implanting electrodes in the brain to monitor seizure activity. Once the electrodes are inserted in the brain, we ask the patients if they are willing to participate in short experiments for us. We can record from single neurons to test different hypotheses.”

Brain activity recordings captured time-sensitive neurons firing during specific moments in time between quizzes, regardless of the image.

The neurons still tracked time even during 10-second gaps with no images while the participants waited, which led the researchers to decode different moments in time based on the activity of the entire group of neurons. 

As well as finding this complex process in the brain, the study’s results provide hope for those with conditions that affect memory and the ability to process time, including Alzheimer’s and Dementia, as they could lead to treatments for those suffering from various memory problems.

The results demonstrate the human brain contains time-tracking neurons. The complete study is published in the Journal of Neuroscience.

Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548359/
https://www.pnas.org/content/117/45/28463
https://www.jneurosci.org/content/early/2021/06/18/JNEUROSCI.3157-20.2021