For 'time cells' in the brain, what matters is what happens in the moment

Our memories are interwoven with time.

The moment of weightless dread, the glimpse of wet leaves on the road ahead, and then the painful impact are all relived in the brain when you recall a childhood fall from a bike.

The sequence has been embedded in the memory thanks to time cells.

When a notable event is detected by the brain, time cells start a highly orchestrated performance.

He said that the cells fire in a sequence. Cell one might fire immediately, but cell two waits a bit, followed by cell three, cell four, and so on."

A time stamp is placed on an unfolding experience as each cell fires. The same cells fire in the same order when we remember something mundane.

Howard says that if he remembers being in his kitchen and making a cup of coffee, the time cells that were active at that moment are re-activated. Your brain replays the moments of the grinder's growl, the smell of Arabica, and the steam rising from a mug every time you think of them.

The system seems to explain how we can travel back in time and relive our life experiences. Time cells play an important role in imagining the future.

Without time cells we wouldn't have order.

Several groups of people were given a tour of the campus by scientists. Change can be found in a vending machine and drinking from a water fountain on the tour.

The participants were asked to remember their experiences. The events in chronological order were remembered by people with typical brains. Those who have damage to the hippocampus recall events without taking into account the order in which they happened.

Cells with a rhythm of their own

In the rat hippocampus, time cells were found. Confirmation of the cells' presence in the brain was made in 2020.

Time cells do not have the same behavior as a clock. The ticks and tocks seem to follow rules that are not related to time.

Time cells hit hot oil at the beginning of any new event. A lot of time stamps are created. The firing becomes less frequent as seconds go by.

He says the sequence doesn't unfold the same way. The interval between firings gets bigger and bigger, leaving less and less time stamps. As time gets further into the past, your ability to distinguish time decreases.

It is not clear how the brain decides how many time stamps to put down. Howard is a scientist who believes in a mathematical approach.

Howard says that time cells allow them to represent time in a compressed way. The brain uses a mathematical tool called a Laplace transform to navigate between the real world firing of neurons and their representation in memory, according to him.

Howard and a team of scientists came up with this explanation. Studies show that time cells' actual behavior is in line with the theory.

Howard says it has worked out well so far.

Biological changes can affect a mathematical approach to time.

Evidence shows that the behavior of time cells is influenced by emotion. The brain puts more time stamps on terrifying events than on mundane ones. Skydivers tend to underestimate the length of a remembered freefall.

Howard says networks of time cells can stretch or shorten time.

Howard believes that we can recognize a word even when it is spoken slowly. Imagine hearing the word stretched out over a long period of time.

The relative shape of the syllables makes it easy to recognize that as seven. A network of time cells can change the duration of the syllables.

To the brain, time and place are connected

Time cells work on their own.

They're not the only part of the brain's system for organizing episodic memories.

There areodic memories for events. Semantic memories are similar to the name of your friend's ferret.

The time cells keep a record of when. Place cells keep a record of where you were when the episode happened.

The hippocampus is an area of the brain that is involved in both memory and navigation. They have been found in other parts of the brain.

Buzski says that neither place cells nor time cells are easy to understand. If the brain is paying attention to where instead of when, a time cell can act like a place cell.

In a science paper, we showed that 100% of the cells in the brain can be placed or time cells.

It makes sense that people talk about time and distance in the same way. Ask someone how long it will take to get to the next town and they may say 10 minutes.

There is a bigger problem with the idea of time cells.

He says the brain doesn't produce time. The brain can't sense time because it isn't important.

Albert Einstein believes that time is illusory. In any event, time doesn't matter to the brain, according to Buzski. Change and the sequence of events are important.

You have to remember that you heard the snake's rattle before you felt it. The amount of time that the whole experience took is unimportant.

This story is part of our periodic science series called "Finding Time", which explores what makes us tick.