Physiologists reveal new facts about activation of mirror neurons

Within the framework of a joint project, supported by the Russian Foundation for Basic Research - TSU and National Research Center Kurchatov Institute conducted a number of experiments aimed at studying the activation of mirror neurons in humans upon observing, pronouncing, and mental reproducing of emotional and neutral words. Particularly, the researchers tested the reliability of the EEG mu-rhythm as a marker for the activation of mirror neurons and found out additional factors, affecting the result.

Psychophysiologists from all around the world use the EEG mu-rhythm as a marker for the activation of mirror neurons.

- It is known, that the mirror neurons (MN) are excited upon performing a certain action, observation of an action performed by others, and recollection of this action. It is believed, that it is these neurons determines the human ability to learn, particularly, the development of speech and language – underlines Yurii Bushov, head of the Department of Human and Animal Physiology, Biological Institute (TSU). To obtain precise data about the functioning mechanism of MN we need reliable markers of their activation. One of the main indicators is depression of the EEG mu-rhythm, registering in the area of the vertex. During the experiments, we were studying the activation features of MN and assessing the reliability of this marker.

As test subjects, we invited 40 young people between 18 and 31, mostly students of the university Faculty of Geology and Geography and Biological Institute (all right-handers). During the experiments, physiologists observed the course of the activation of MN upon observation, pronunciation, and recollection of neutral words Pain and One. Along with this, they studied the work of MN upon observation and perception of short time intervals.

The research team analyzed spectral and correlation characteristics of the EEG mu-rhythm with a frequency of 8-13 Hz and found out that this rhythm reflects the activity of communicative MN. This is demonstrated by its depression upon observation, pronunciation, and mental recollection of words.

- It turned out, that an effect depends on the rhythm frequency, on type and stage of performed activity, and on the brain lateral organization. This proves, that we should more carefully work with the mu-rhythm since serious errors are possible – adds Yurii Bushov. The study results were presented at the 19th World Congress of Psychophysiology, held this September in Lucca (Italy).

Based on the present results, the university research team put forward its own hypothesis about the functioning of MN. Since the activation of MN occurs upon observing only familiar actions, they assumed that MN are not responsible for the understanding of intentions, but for searching finished motor program and its extraction from long-term memory. The team is going to verify this assumption using MRI data obtained by the Kurchatov Institute.

Yurii Bushov underlines, that the study of MN functions will allow understanding the causes of many cognitive impairments and to outline correction methods, including overcoming difficulties in learning a foreign language and treating autism and diseases, associated with memory impairment