Research discovers how associative memories are formed


Sep 25, 2021 10:05 PM STI

Washington [US], Sep 25 (ANI): In a recent study, neuroscientists discovered specific types of neurons in the brain’s memory center that are responsible for acquiring new associative memories, i.e. say the ability to remember relationships between unrelated items.
The results of the study conducted by scientists at the University of California at Irvine were published in the journal “Nature”.
Psychologists began to study associative memory in the 1800s, with William James describing the phenomenon in his 1890 classic The Principles of Psychology.
Scientists today agree that the structures responsible for forming associative memory are found in the median temporal lobe, or the famous “memory center” of the brain, but the particular cells involved and how these cells are controlled have remained a mystery until now.
This study also uncovered how these associative memory neurons are controlled.
We rely on associative memories in our daily lives and this research is an important step in understanding the detailed mechanism of the formation of these types of memories in the brain.
“Although associative memory is one of the most basic forms of memory in our daily lives, the mechanisms underlying associative memory remain unclear,” said lead researcher Kei Igarashi, professor at the Center for Neurobiology at the learning and memory and assistant professor of anatomy and neurobiology at the UCI Faculty of Medicine.

The study first reported that specific cells in the lateral entorhinal cortex of the medial temporal lobe, called fan-shaped cells, are needed to acquire new associative memories and that these cells are controlled by the chemical dopamine. brain known to be involved in our experience of pleasure or reward.
In the study, the researchers used electrophysiological recordings and optogenetics to record and monitor the activity of ventilator cells in mice as they learn to associate specific smells with rewards.
This approach led researchers to discover that ventilator cells calculate and represent the association of two new, unrelated elements (smell and reward).
These fan-shaped cells are necessary for the successful acquisition of new associative memories. Without these cells, the pre-learned associations can be recovered, but the new associations cannot be acquired. In addition, the acquisition of new associations also requires dopamine.
“We didn’t expect dopamine to be involved in the memory circuit. However, as the evidence gathered, it gradually became clear that dopamine is involved,” said Igarashi.
“These experiments were like a detective story to us, and we are thrilled with the results,” added Igarashi.
This discovery is an important piece in the puzzle of understanding how memories form in the brain and lays the foundation upon which other researchers can continue to build.
It is known that associative memory capacities decrease in neurodegenerative diseases such as Alzheimer’s disease.
Understanding the neurobiological mechanism of the formation of these memories is the first step in the development of therapies to slow the loss of associative memory capacities in Alzheimer’s disease. (ANI)


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