The subcortical-cortical integration with their relatively small genetic and phenotypic variation (Shepovalnikov, Tsitseroshin, 2007) have a sexual dimorphism, studied in ontogenesis in less detailed compared to the inner – and interhemispheric cortical zones interactions (Panasevizch, 2010). In this regard the general differences research of the most informative EEG-parameters – the full amplitude spectrum (FAS) a wide frequency range of 50 persons (27 males and 23 – female) in a singular ontogenetic range from 3 to 70 years was hold. The 21-channel electroencephalograph "Neiron-Spektr-4/VP" company Neirosoft was used ("10-20" by Jasper, the reference electrodes were placed on the ear lobes). Evaluating the average values PAS in 21 leads without considering the individual rhythms, intersexual differences this neurodynamic parameter is not found. Taking in consideration the separate EEG-rhythms (beta- high-frequency, low-frequency beta, alpha, theta, delta) revealed that sex differences are unknown, and in some cases – quite substantial. A priori the supposition of determined generalization level role, different for different EEG-rhythms (Kuksova, 2009) in gender differentiation formation of this kind aroused. There is the distinct tendency to the higher absolute values PAS men EEG-rhythms than women in this paper. In extreme values of the studied EEG frequency spectrum (high-beta, and delta-slow rhythm), this trend has gained a reliable character (P <0.05) mainly in the posterior temporal and anterior-frontal leads. Stable negative correlation (P <0.05) between the absolute values of the different FAS EEG rhythms and the age of the subjects, expressed not in years, but in months, showed a gradual decrease in the value of this indicator as they mature and aging in the studied ontogenetic series. The regularity prevailed in the direction of convexital surface to a depth of (beta → alpha → theta→ delta), which coincided with the data obtained in our laboratory (Vodolazhskaya, 2009.2010). In males this pattern manifested itself more clearly than in females. The male number of effective (P <0.05) leads in the spectrum was distributed as follows: "3 (beta) → 13 (alpha) → 21 (theta) → 21 (delta), and women as foll ows:" 4 (beta) → 4 (alpha) → 17 (theta) → 18 (delta). This shows that the most striking intersexual differences reported with respect to FAS basic rhythm of EEG. The fall of this magnitude neurodynamic in ontogeny from three to seventy years of age is more pronounced in men than in women, which probably compensated for initially more expressions of male status of the full amplitude electroencephalographic rhythm compared with women.
We examined the influence of the type of radio program on the memory for radio advertisements. We also investigated the role in memory of the typicality (high or low) of the elements of the products advertised. Participants listened to three types of programs (interesting, boring, enjoyable) with two advertisements embedded in each. After completing a filler task, the participants performed a true/false recognition test. Hits and false alarm rates were higher for the interesting and enjoyable programs than for the boring one. There were also more hits and false alarms for the high-typicality elements. The response criterion for the advertisements embedded in the boring program was stricter than for the advertisements in other types of programs. We conclude that the type of program in which an advertisement is inserted and the nature of the elements of the advertisement affect both the number of hits and false alarms and the response criterion, but not the accuracy of the memory.
Spontaneous fluctuations of brain activity explain why a faint sensory stimulus is sometimes perceived and sometimes not. The prevailing view is that heightened neural excitability, indexed by decreased α oscillations, promotes better perceptual performance. Here, we provide evidence that heightened neural excitability instead reflects a state of biased perception, during which a person is more likely to see a stimulus, whether or not it is actually present. Therefore, we propose that changes in neural excitability leave the precision of sensory processing unaffected. These results establish the link between spontaneous brain activity and the variability in human perception.
The magnitude of power in the alpha-band (8–13 Hz) of the electroencephalogram (EEG) prior to the onset of a near threshold visual stimulus predicts performance. Together with other findings, this has been interpreted as evidence that alpha-band dynamics reflect cortical excitability. We reasoned, however, that non-specific changes in excitability would be expected to influence signal and noise in the same way, leaving actual discriminability unchanged. Indeed, using a two-choice orientation discrimination task, we found that discrimination accuracy was unaffected by fluctuations in prestimulus alpha power. Decision confidence, on the other hand, was strongly negatively correlated with prestimulus alpha power. This finding constitutes a clear dissociation between objective and subjective measures of visual perception as a function of prestimulus cortical excitability. This dissociation is predicted by a model where the balance of evidence supporting each choice drives objective performance but only the magnitude of evidence supporting the selected choice drives subjective reports, suggesting that human perceptual confidence can be suboptimal with respect to tracking objective accuracy.