PNAS: Long-term memory is related to order, not just repetition

A new study by a team of neuroscientists suggests that long-term memory relies on the repetition of events and complex neural learning processes to make these memories persist
.

Nikolay V.

He added: "For example, neurons can distinguish between the order in which the intensity of two events increases and the intensity of the same two events in opposite order, and only when the intensity increases over time, memories
are formed.

The researchers also included Thomas Carew, a professor at the Center for Neuroscience at New York University, and Tasnim Tabassum, a researcher at New York University, who sought to better understand the reasons behind a well-documented neural process — specifically, repeated events that induce long-term memory, while individual events cannot
.

What is unclear is how repetitive events interact to
form memories.

To explore this question, the scientists studied the California sea slugs (Aplysia californinica
).

Kukushkin, a researcher at New York University's Center for Neuroscience and a clinical assistant professor at New York University Liberty Research, explains: "Two-trial learning is a technique that, after two experiences, can cause sea hares, or even isolated sea hare neurons, to form long-term memories
.

As part of these experiments, the researchers specifically examined the activity
of the protein ERK, which is necessary for memory.

Previously, scientists believed that the activation of ERK should accumulate during the learning process
.

They noticed that after only one trial, the failure party of the "tug-of-war" prevailed, and the ERK activity was blocked, preventing the formation
of memories.

The scientists used different variants of the training program — which had different effects on memory depending on
the pattern of stimulation.

Kukushkin explains: "The formation of long-term memories depends on which side wins the ERK tug-of-war over time
.

essay

Precise timing of ERK phosphorylation/dephosphorylation determines the outcome of trial repetition during long-term memory formation