APR 13, 2020 3:32 PM PDT

The Memory Cells that Help Us Interpret Different Situations

WRITTEN BY: Annie Lennon

Neuroscientists from MIT have identified cell populations that encode different parts of an overall experience. Like the neural code used to recall detailed memories of different locations, these cells are also stored in the hippocampus. Rather than being activated by different location settings however, they are activated whenever similar experiences occur. 

It has been known for some time that memories of specific locations are stored in certain cells in the brain’s hippocampus. Research conducted on mice for example has shown that neurons known as place cells activate when the animal is placed in a certain location, and if they dream about it. 

For this study, researchers from MIT wanted to understand whether the hippocampus also stores information on more abstract parts of memories. In particular, they wanted to know whether hippocampal cells would also activate when experiencing certain tasks, such as looking through a menu or eating a dessert, regardless of location. 

To see whether this would be the case, the research team designed an experiment in which they measured the neuronal activity in the CA1 region of the mouse hippocampus as they ran a four-lap maze. At the end of every fourth lap, the mice were given a reward. 

As hypothesized, the researchers noted that place cells fired up at different points along the track. They also found that another set of cells were fired up during one of the four laps, although not others. 

To see whether this meant that the mice were also recording chunks of experiences beyond location, the researchers then trained the mice to run a square maze on one day and a circular maze on another, once again receiving a reward every fourth lap. While place cells changed in activity (as expected according to the new environments), they found that the same sets of lap-specific cells fired up during each of the four laps, regardless of the track. These lap-coding cells behaved the same even when laps were made longer or shorter at random. 

"Even in the new spatial locations, cells still maintain their coding for the lap number, suggesting that cells that were coding for a square lap 1 have now been transferred to code for a circular lap 1,” says Chen Sun lead author of the study, 

From these results, the researchers theorize that the hippocampus consists of ‘two mutually and independently manipulatable codes’. While one encodes factors like location, time and sensory input, the other breaks an overall experience down into smaller categories that fit into consistent experiences like ‘drinking tea’ or ‘reading a book’. 

Susumu Tongawa, senior author of the study, said about the two hippocampal codes: “If we want to remember all the details of what happened in a specific experience, moment-to-moment changes that occurred, then the continuous monitoring is effective. But on the other hand, when we have a longer experience, if you put it into chunks, and remember the abstract order of the abstract chunks, that's more effective than monitoring this long process of continuous changes."


Sources: Big Think, MIT News


About the Author
  • Science writer with keen interests in technology and behavioral biology. Her current focus is on the interplay between these fields to create meaningful interactions, applications and environments.
You May Also Like
MAR 01, 2020
Genetics & Genomics
MAR 01, 2020
Treating Huntington's Disease With a Gene Therapy That Targets Brain Cells
A new therapeutic approach for Huntington's disease may aid patients with other neurodegenerative disorders.
MAR 09, 2020
MAR 09, 2020
Mobilizing the brain's immune cells boosts memory
A study by researchers at Australia’s RMIT University has uncovered a surprising connection between immune cells i ...
MAR 13, 2020
MAR 13, 2020
Advancing Brain-Machine Interfaces
At Stanford University, researchers have designed a device that connects the brain to silicon-based technologies. Althou ...
APR 02, 2020
Cell & Molecular Biology
APR 02, 2020
Cooling Injured Brain Cells Can Aid Recovery
According to the CDC, in 2014 there were around 2.87 million incidences of TBI-related ER visits.
APR 19, 2020
Plants & Animals
APR 19, 2020
Flamingos Understand the Value of Friendship
Most of the time, wild flamingos are observed in massive flocks as opposed to hanging out on their own. It’s evide ...
MAY 26, 2020
MAY 26, 2020
Imitating Babies Allows Bonds to Form Quickly
Researchers from Lund University in Sweden have found that 6-month old babies know when an adult imitates them- and that ...
Loading Comments...