engleski

Cognitive event-related potentials: method for testing features of working memory using the Sternberg memory task

Different kinds of cognitive impairments have specific influence on a working memory. Most of the methods used in a routine cognitive testing of a working memory are behavioral methods and these methods could sometimes be submissive to the influence of patients. The aim of our research is to establish reliable and quantitive neurophysiological method appropriate for patients with different kinds of cognitive impairments for testing features of the working memory. In order to achieve that we examined cerebral dynamics that occurs as a result of memorizing and retrieving information from working memory using modified Sternberg memory task. Twenty-one (14 male and 7 female) healthy right handed adults (mean age 23.38 +/- 1.19) with no auditory impairments participated in the study. In the Sternberg experiment, sets of two or four digits were acoustically presented to subjects. After the last item in the set, the target digit (probe) was presented. Participants had to indicate whether the probe did (positive probe) or did not (negative probe) belong to the presented set by pressing appropriate buttons. Results of the study are cognitive auditory event-related potentials and associated reaction times. Obtained results show that the increase of the memory set size would elicit the increase of the reaction time and the increase of the latency of the specific component of event-related potentials (P300 – the cognitive component). The activity in the period in which participants rehearse the previously presented set is stronger expressed for the set consisted of less digits (two). The amplitude of the cognitive component is greater for the positive probe than for the negative probe and the latency of the cognitive component is greater for the negative probe. Findings coming out of this research show that cognitive event-related potentials are an appropriate method for testing features of the working memory. They are in accordance with the presently accepted theory. These findings are being used in order to make a clinical diagnostic method appropriate for patients with different kinds of cognitive impairments.

cognitive event-related potentials; working memory; Sternberg

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