A common feature of the research activity of the Psychophysiology Research Group is the investigation of psychophysiological mechanisms related to aging. The importance of this topic is underscored by the fact that in aging societies - which is a world-wide tendency - numerous economical, health-related, psychological, etc. problems arise posing difficult issues to be solved. In order to be able to achieve optimal quality of life in old age it is essential to have appropriate knowledge concerning the intricate mechanisms of the aging process itself. Among the topics investigated in this vast field by the Research Group clinical issues are also included: the decline of mental activity preceding Alzheimer's disease and the identification of its electrophysiological markers may be important as indicators of the onset of an irreversible process.
Most of the studies of the Research Groups are performed by using electrophysiological methods, another common characteristic feature of its research activity. In some of these the event- related potential technique is used. This method takes advantage of the fact that electrophysiological methods are capable of following various functional changes in the nervous system - including those that are related to information processing - with a remarkably better time resolution capacity compared to other methods. In addition to evoked potentials, the Research Group - capitalizing on the explosion-like developments taking place in this field in recent years - uses quantitative electrophysiological indices characterizing dynamic changes of neuronal networks. By these means a completely new type of information, inaccessible by other methods, can be obtained with respect to the properties and the changes of interneuronal connectivity patterns - having fundamental importance from the point of view of information processing, besides other functions.
Studies performed by the Psychophysiology Research Group are the following:
Bioelectrical correlates of age-related interaction of emotional and cognitive processes
Competition in an aging society: psychophysiological mechanisms of risk-taking
The age-dependent effect of training on task-switching - electrophysiological correlates
Psychophysiological aspects of age-dependent changes of memory functions in healthy people and in mild cognitive impairment
Electrophysiological correlates of age-related changes of mathematical cognition
Most important results
Results of the analysis of evoked potentials evoked by words with emotional valence and the accompanying synchronization processes show that processes related to response inhibition are activated most effectively by stimuli having aversive effect, which is more conspicuous in young subjects. Independent of the eliciting stimulus higher synchronization was observed in young subjects probably reflecting on more efficient interneuronal connections in this age group. On the other hand, enhanced synchronization evoked by positive stimuli in the elderly may be a correlate of the"positivity effect", regarded as a characteristic feature of old people.
As a result of cognitive training short -term memory, psychomotor speed, and task performance improve. These changes can be appropriately studied by event-related potentials. The results show that brain plasticity is retained in old age but the transfer effect between various tasks is limited.
In tasks with visual verbal memory load increased synchronization was observed in certain EEG frequency bands within and in between the frontal and parietal regions. During the performance in various memory tasks the level of synchronization correlates with the amount of information to be maintained. Compared to the young, in the elderly individuals task-evoked synchronization increase cannot be observed or occurs only on a lower level.
During mental arithmetic task performance, neuronal network properties computed by using brain electrical activity shift towards the "small-world" network topology, representing optimal information processing condition.
Analysis of brain electrical activity by the tools graph-theory quantifying modularity in individuals diagnosed with "minimal cognitive impairment" (MCI) obvious differences can be seen between healthy elderly people and MCI patients. In the latter the decline of neuronal connectivity affecting first of all the frontal areas is observed.
