(ORDO NEWS) — Researchers from the United States have found that activity in the amygdala, the hippocampus, is responsible for emotional memory.
And in depression, when memory impairment is often observed, disturbances occur in the electrical activity of this area of the brain.
Most people remember events that are more emotional for them than neutral ones. In fact, the day of one’s own wedding is remembered better than an ordinary worker.
Scientists from the Universities of Pennsylvania and Columbia, the National Institutes of Health and the Icahn School of Medicine at Mount Sinai (USA) decided to study this issue in more detail.
Most studies of neural mechanisms are done in animals because they require direct access to the brain to record brain activity and perform experiments that demonstrate a particular process, such as the destruction of neural circuits.
However, in animal studies, it is difficult to observe or characterize such a phenomenon as improved emotional memory.
To study this process in humans, scientists set up a series of experiments involving 148 patients with epilepsy.
In the first test, 147 subjects were given direct intracranial recording of brain activity to localize and treat seizures, while people completed an episodic memory task.
Participants memorized lists of various words, and electrodes placed in their hippocampus and amygdala recorded the electrical activity of the brain.
The researchers found that subjects were better at remembering words that had the potential to be more emotional (dog, knife) than neutral ones (table).
The researchers noticed that whenever participants memorized emotional words, high-frequency neural activity became more active in the amygdala-hippocampus circuit.
When the subjects memorized more neutral words or could not remember one word or another at all, there was no such pattern.
This fact made scientists think, because the use of therapeutic intervention on the amygdala zone – the hippocampus, may improve memory.
The second experiment was carried out with the participation of 19 patients from the same group.
The authors of the work were able to show that the application of high-frequency electrical stimulation to the hippocampus selectively reduced memory for emotional stimuli, while reducing high-frequency activity in the hippocampus itself.
Based on this, the experts concluded: if you turn off brain activity that correlates with emotional memory, then the latter will naturally decrease.
Finally, in the next experiment, the researchers analyzed the change in emotional memory and, in parallel, the participants’ own assessments of mood and general self-perception.
In 19 people who were diagnosed with depression, the researchers observed a simultaneous decrease in emotional memory and high-frequency activity in the hippocampus and amygdala.
Scientists hope that their work will lay the foundation for new research that studies memory disorders and is aimed at combating them.
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