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We previously showed that neuronal activity in beta frequency might serve as a carrier for attentional arousal within the visual system of cat. In the present study, we adopted the animal paradigm for anticipatory attention to study alertness-related changes of beta activity in human subjects. The results indicated that increased alertness, manifested by(More)
Older adults (>60 years) show attentional deficits in comparison to younger people (18-30 years). As beta-band EEG activity has been previously postulated to indicate attentional modulation in the visual system, we searched for possible deficits in beta power in elderly subjects performing an attentional task with spatial differentiation between visual(More)
Depression is a disorder characterized not only by persistent negative mood, lack of motivation and a "ruminative" style of thinking, but also by specific deficits in cognitive functioning. These deficits are especially pronounced when integration of information is required. Previous research on linear syllogisms points to a clear pattern of cognitive(More)
For about two decades now, the localization of the brain regions involved in reasoning processes is being investigated through fMRI studies, and it is known that for a transitive form of reasoning the frontal and parietal regions are most active. In contrast, less is known about the information exchange during the performance of such complex tasks. In this(More)
The number of items that can be held in human short-term memory (STM) is limited to 7 (± 2) elements. Lisman and Idiart's theoretical model of STM proposes that this value depends on the number of gamma cycles that can fit in one theta cycle. Previous studies on animals and humans provided support for this hypothesis but direct evidence from human EEG scalp(More)
The aim of this study was to investigate the relationship between working memory capacity (WMC) and frontal theta response to memory load in Sternberg task. We show that oscillatory activity in the theta band (4-6 Hz) related to Sternberg task performance may differentiate people characterized by high and low WMC. Specifically, there is a linear increase of(More)
As a comment on Kurzban et al.'s opportunity cost model, we propose an alternative view of mental effort and the action selection mechanism in the brain. Our hypothesis utilizes local resource depletion within neuronal networks, which justifies from a neurophysiological perspective why mental fatigue diminishes after switching to a novel task and explains(More)
Previous imaging studies have identified many brain regions activated during reasoning, but there are differences among the findings concerning specific regions engaged in reasoning and the contribution of language areas. Also, little is known about the relation between task complexity and neural activation during reasoning. The present fMRI study(More)
We studied the dynamical pattern of transmission involved in the information processing during cognitive experiments engaging working memory. The ensemble averaging approach was used to fit a multichannel autoregressive model to the EEG signals recorded during the transitive reasoning task. The short-time directed transfer function was estimated for finding(More)
The dynamic pattern of functional connectivity during a working memory task was investigated by means of the short-time directed transfer function. A clear-cut picture of transmissions was observed with the main centres of propagation located in the frontal and parietal regions, in agreement with imaging studies and neurophysiological hypotheses concerning(More)