Nerd cells, ‘super calculating’ network in the human brain discovered

Summary: Newly identified “nerd cells” code for speed, direction and position at once.

Source: University of Oslo

Are you impressed when NASA manages to calculate the time and speed of a rocket’s orbit? A new study from the University of Oslo shows that your brain has a “nerd center” capable of even more complex calculations.

If you see the bus coming late on your way to work and running to get it while carrying your cup of coffee, you probably beat NASA. Nerve cells in your brain perform billions of complicated mathematical calculations to determine your speed, position and direction. For years, this ability of the brain to calculate such parameters was a mystery.

After five years of research into the theory of the continuous attractor network, or CAN, Charlotte Boccara and her group of scientists at the Institute of Basic Medical Sciences at the University of Oslo, now at the Center for Molecular Medicine Norway (NCMM), have made a breakthrough. .

“We are the first to clearly establish that the human brain actually contains such ‘nerd cells’ or ‘super calculators’ that the CAN theory advances. We found nerve cells that code for speed, position and direction all at once,” says Boccara.

1,400 nerve cells

Boccara analyzed 1400 nerve cells registered in rats, spread over different brain regions. Together with Ph.D. colleague Davide Spalla and researcher Alessandro Treves, she recently published an article in: nature communication titled “Angular and Linear Speed ​​Cells in the Parahippocampal Circuits.”

“We equipped rats with small brain probes with very thin electrodes that could read their brain activity. Then they could roam freely in a maze in search of treats. We could track their movements with a camera and correlate their actions with the activity of many nerve cells from which we recorded,” explains Boccara.

Boccara’s research group used an advanced form of data analysis to thoroughly investigate what was happening in all the cortical layers of different brain regions. This involved systematic examination of huge data sets.

This new research builds on the groundbreaking work of John O’Keefe, May-Britt and Edvard Moser (Nobel Prize in Medicine, 2014), who show that individual nerve cells can code for a navigational coordinate system – the brain’s GPS system.

A missing piece of the puzzle that could be important for Alzheimer’s research

The CAN theory that Boccara is investigating has been popular among scientists for decades. In a nutshell, it proposes that as we move, our mental map or representation of where we are located constantly updates itself according to our new position.

The CAN theory hypothesizes that a hidden layer of nerve cells performs complex math and collects vast amounts of information about speed, position and direction, much like NASA scientists do when adjusting a rocket’s orbit.

“Previously, the existence of the hidden layer was just a theory for which there was no clear evidence. Now we’ve managed to find robust evidence for the actual existence of such a ‘nerd center’ in the brain,” the researcher says, and as such fills in a piece of the puzzle that was missing.

The area where Boccara and her team found this hidden layer is exactly the part of the brain first affected at the onset of Alzheimer’s disease.

“Our findings are important because these cells tell us where we are and how we move. If they stop working, people lose their way,” explains Boccara.

Understanding the inner mechanisms of brain coding can later be applied to develop new therapies.

Why are the nerve cells discovered by Boccara scattered over different parts of the brain? And can they possibly perform multiple tasks?

“Here we have some theories: Do some cells function as backups, or do they perform separate calculations, that is, some cells plan while others respond to previous experience?” she asks.

The brain is bombarded with sensory experiences at all times (seeing, feeling, hearing). It must give meaning to this chaos to create an image coherent with memories of similar situations experienced before in order to modify one’s actions. For example, I see the bus coming, I feel the coffee is hot; at what speed can i run to reach the bus without burning myself?

Boccara analyzed 1400 nerve cells registered in rats, spread over different brain regions. Image is in the public domain

In recent years, the research community has proven that the brain regions Boccara is interested in are involved in many more tasks than mapping spatial position. The nerve cells there can also map sounds and rewards. Now she wonders if the cells found can perform other tasks in addition to calculating speed and direction.

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“But how such phenomena are perceived changes depending on the experiences you have. For example, the way you perceive the name Ola changes significantly when you meet an Ola who becomes your partner. The categorization process should therefore be adjusted over time. updated and the geek center can also be involved in this process, which is an interesting field for further research,” says Boccara.

Boccara now wants to find out how poor sleep affects the nerd cells’ computing power.

“I wonder if the reason why the brain slows down when we’ve had too little sleep has something to do with abnormal activity in these cells,” she says.

About this neuroscience research news

Writer: press office
Source: University of Oslo
Contact: Press Office – University of Oslo
Image: The image is in the public domain

Original research: Open access.
“Angular and linear velocity cells in the parahippocampal circuits” by Davide Spalla et al. nature communication


Abstract

Angular and linear velocity cells in the parahippocampal circuits

An essential role of the hippocampal region is to integrate information to calculate and update representations. How this ends is up for debate.

Many theories are based on the integration of self-motion signals and the existence of continuous attractor networks (CAN). CAN models hypothesize that neurons encoding navigational correlates — such as position and direction — receive input from cells subjunctive encoding position, direction and self-motion. To date, there is very little data on such conjunctive coding in the hippocampal region.

Here we report neurons encoding angular and linear velocity uniformly distributed across the medial entorhinal cortex (MEC), presubiculum, and parasubiculum, except MEC layer II. Self-motion neurons often conjunctively coded position and/or direction, but lacked a structured organization.

These results provide insight into how linear/angular velocity – derivative over time of position/direction – may allow updating spatial representations, potentially revealing a general algorithm to update each representation.

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