Functional Brain System during Probabilistic ForecastingстатьяТезисы
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 30 декабря 2016 г.
Аннотация:Functional systems associated with the probabilistic forecasting were researched. Probabilistic forecasting is a process of making a decision when multiple solutions are available. Participants (N=28) were shown with quasirandom sequence of three digits (1, 2, 3). A digit was presented for 700 ms followed by a 1500 ms pause. The participant’s task was guess what the subsequent digit would be and press the corresponding button. Each participant also completed two control tasks: a perception test (which required pressing the button of the presented digit) and a memory test (1-back). After the EEG registration, ERP calculation and filtering the results (MFS algorithm, Vartanov, 2002) dipole sources were localized (two-dipole dynamic model, KD≥0.95, Talairach’s coordinates). The relative frequency of a dipole appearing at a specific brain structure during a 100 ms period was calculated. To do so an ERP was divided into 10 overlapping periods with 50 ms shifts. Using the T-test, the significant dipole spacing differences (p≥0.05) between the three tasks for a group of participants were revealed. The brain structures in which there was a difference for at least one period were selected. Then a factor analysis with Varimax rotation was performed. Three factors were revealed. The factor loading allocation fully corresponded with the experimental assignments thus allowing for the interpretation of these factors as functional systems. Calculating the factor scores allows localizing these functional systems in the brain. The system of probabilistic forecasting (factor 1) includes the following associated structures listed according to their contribution to the system: right midbrain, right inferior frontal gyrus, left superior temporal gyrus, left parahippocampal gyrus, right posterior cingulate, right parahippocampal gyrus, left BA (Brodmann area) 47, left orbital gyrus, right BA 25, right temporal lobe sub-gyral, right BA 30, left putamen, left amygdala, left brainstem, right cingulate gyrus, left cerebellum. The highest activation of this system was observed around 200-300 ms after presentation of a stimulus. We suppose that the system evaluated the efficiency of the last forecast and the improvement of the following assumption. This corresponds with the previously obtained data that basic decision making model consists of two interactive schemes: evaluating each variant and selecting the best possible. During the other two tasks the activation of this system was 4 times lower and was only observed around 50-150 ms after presentation of a stimulus. The research was supported by the Russian Science Foundation (project № 16-18-00066).