The current study is devoted to the study of brain mechanisms of cognitive control – the set of interrelated processes guiding goal-directed behavior.
Goal of research:
The current study focused on the search and description of deep hidden mechanisms of adaptive decision making within the system of cognitive control.
Methods and empirical base of research:
During the current study, we recorded magnetoencephalographic and electroencephalographic activity during implementation several behavioral tasks, which were developed in our laboratory on the basis of the condensation task. Such experimental tasks create high cognitive load and they proved to be efficient in the previous experimental studies by our laboratory. During the current study, we conducted three psychophysiological experiments. Participants were recruited as volunteers among HSE students as well as through social networking.
We used a set of modern advanced mathematical and statistical methods to process psychophysiological signals, such as time-frequency analysis, threshold-free cluster enhancement, minimum norm estimation, common spatial patterns, trial-to-trial correlations, and the analysis of phase-locking.
Results of research:
The present study produced the following main results.
We for the first time demonstrated the possibility of studying theta oscillations during performance of tasks involving the cognitive control, using the method of magnetoencephalography. In the course of this study, we obtained direct evidence of a distributed localization of theta effects in the cerebral areas extending far beyond the medial prefrontal area, which was traditionally studied as a sole source of theta oscillations evoked in relation to the processes of the cognitive control.
Using the trial-and-error learning, we for the first time demonstrated that feedback signal bears two functions, each of which has its own spatial and temporal signatures in the brain activity: the unsigned response to the feedback signal (non-specific response, related with the implementation of the “need for cognitive control), and the sighed response (specific response, which triggers adaptive transformations following the feedback signal).
We for the first time demonstrated that the method of common spatial patterns can be applied to the study of the cognitive control. With the help of this method, we discovered the correlates of the feedback effect after slow erroneous behavioral responses, which were committed under the conditions of high internal uncertainty. This supports our hypothesis that we put forward earlier; according to this hypothesis, under slow behavioral responses outcome detection is possible only via an external feedback signal.
By using a set of innovative methods of mathematical analysis of electroencephalographic and magnetoencephalographic signals, we studied and described in high details the picture of brain processes of cognitive control during implementation of the task involving high cognitive load. Particularly, we demonstrated that the power of frontal theta oscillations during slow correct behavioral responses was positively correlated with the response time. Slow responses involve attentional lapses and the state of the internal uncertainty, which lead to compromised sensory processing and degraded information integration in relation to the stimulus-to-response mapping needed for correct performance on the task. Thus, enhanced midline theta oscillations preceding the response can reflect the recruitment of cognitive resources for making a motor choice in the state of internal uncertainty.
Using the method of recording participants’ behavioral responses with a computer mouse, we for the first time demonstrated that the movement initialization time affects the ERN amplitude, while the movement duration affects the Pe amplitude. This allowed us to distinguish between the two types of internal uncertainty, one of which precedes the behavioral response and the other one follows it.
Novelty, importance, and practical applicability of the results:
The current study was novel due the methodological innovations: we used new experimental approaches aiming at the analysis of deep hidden mechanism of decision-making.
Importance of the current study has primarily fundamental nature since it was aimed at the study of deep neurocognitive mechanisms that determine accuracy and precision of human performance within various tasks, as well as mechanisms that provide for flexibility and adaptivity of human behaviour.
This topic is also important for solving a number of applied issues, including labor optimization in science, education, industry, transportation, as well as development of artificial intelligence systems.
The study of the adaptive changes that happen in the brain after errors, can find its important practical applications for development of educational media in many professional areas such as teaching foreign languages, teaching operator performance (including vehicle driving), etc.