Interhemispheric Interaction during Memorization of Movement Rhythm

After memorizing a simple periodical movement in the ankle joint, 36 healthy subjects (right-handers) reproduced it from memory. The movement rhythm image that formed during movement in the left ankle joint was memorized better than when the movement was performed by the right extremity. The specific features of interhemispheric interaction at various stages of trace processes, unequal participation of the hemispheres in perception and processing of information, and the physiological expedience of the signal transmission from the right to the left hemisphere are sufficient to assume a basic sequence of hemispheric functional activity redistribution when the brain masters new cognitive actions.     

Eye Tracking and Interhemispheric Interaction in the Distribution of Spatial Attention

The patterns of visual attention allocation were investigated in healthy subjects (n = 43) and patients with focal brain lesions (n = 17) using the original method developed for eye tracking in patients while memorizing a series of stimulatory image triplets. Two processes were estimated: delayed reproduction and recognition of stimuli in a series of consecutive visually similar distractors. In healthy subjects both processes correlated to a great extent (r = 0.6; p = 0.00001). The most significant disorders of voluntary verbal reproduction were observed when the left hemisphere of the brain was affected. The overall effectiveness of recognition in the case of brain damage decreased without significant dependence on the lateralization of the focus. Some correlation was observed between realized and remembered information and the patterns of visual fixations (concentrated on the semantic parts of the image or chaotically distributed in the space of stimulus exposure). Ineffective patterns of visual fixation in patients were more often observed in the area contralateral to the lesion. These contralateral stimuli were reproduced and recognized less efficiently in comparison with the central and ipsilateral images. Complete ignoring of the contralateral image in the triplet was observed both in the absence of visual fixation and in combination with the diffuse pattern.     

Changes in the EEG-Rhythms in Endogenous Depressive Disorders and the Effect of Pharmacotherapy

The study of a series of EEG indices in endogenous depressive disorders and their changes after pharmacotherapy was conducted. The EEG changes in depressed patients versus healthy individuals were found to be characterized by a significant increase in the relative power of the - and -activity and a decrease in the - and -activity, as well as by a decrease in the regional differences between the anterior and posterior divisions of the brain and an increase in the activity of the right hemisphere in relation to the left hemisphere. The use of amitriptyline, fluoxetine, and moclobemide contributed to the improvement in the mental state, which was accompanied by an increase in the EEG amplitude, a decrease in the relative power of the - and -activity, and an increase in the -rhythm power; however, on discharge, the patients retained deviations from a number of values compared to healthy subjects.     

Polymorphism in the Human Serotonin Transporter Gene in Endogenous Psychoses

Associations of the VNTR-17 and 5-HTTLPR polymorphisms of the serotonin transporter gene with affective disorders, including depression, have been found. These polymorphisms were analyzed in two groups of Russian probands: patients with endogenous psychoses and control individuals without mental disorders (423 and 277 persons, respectively). No associations were found between VNTR-17 genotypes or alleles and the diseases. However, the frequency of10/10 (VNTR-17) homozygotes increased with age in both patients and healthy persons. The results of the analysis of the 5-HTTLPR polymorphism suggest an association of the short (s) allele of the 5-HTTLPR polymorphism with schizophrenia and schizoaffective psychoses, but not with affective disorders.