[Localization of human brain areas activated for chaotic and ordered pattern perception].

The aim of our work was to localize cortical areas involved in the processing of incomplete figures using functional MRI (fMRI) for 8 healthy volunteers (18-30 year old) with the did of anatomical and fMRI fast imaging technique: echo planar imaging (EPI), whole brain scan (36 slices) matrix 64 x 64, 3.7 second. We used 1.5 T MR-scanner and BOLD-method (Blood Oxygenation Level Dependent), based on distinctions of magnetic properties of hemoglobin. Fast imaging technique on modern MR-scanners with > or = 1.5 T provides precise statistical maps of oxygenation increase with high spatial resolution. For test stimuli we used matrix of Gabor grating. We used two types of 10 x 10 matrices with chaotic and ordered orientation of Gabor gratings. The size, brightness and contrast of the stimuli were identical. The chaotic and ordered patterns activated different brain areas. We establish that ordered patterns activated only primary visual cortex - V1 and V2, (BA17-18), wheareas chaotic patterns activated in addition primary visual cortex, the V3,V4,V5 (BA19) of the occipital cortex and the area 7 of parietal area (BA7) classification. Decision making for that task is localized in prefrontal and frontal cortex, including (BA 6, 9, 10).

[The subcortical neuronal correlates of human assessment actions]. / Podkorkovye neironnye korreliaty otsenochnykh deistvii u cheloveka.

In patients with parkinsonism to whom in accordance with medical-diagnostic indices electrodes were implanted into the nuclei of thalamus and striopallidal system, impulse activity of neurones was recorded in tests with presentation of visual and acoustic stimuli. It has been shown that neurones of these structures, reacting by a change of discharges frequency in carrying out the assessing actions by man constitute a special class of neurones, spatially separated from those, connected with the organization of motor acts. The typical feature of neuronal reactions is a high degree of their value dependence on the level of attention. Neurones of the above structures reacts also during preparation of the assessing actions and fixation of their results in the short-term memory.