| Abstract/Results: | ABSTRACT:
Objectives: The aim of the study was the quantitative investigation of the slow negative presaccadic potentials in antisaccadic task depending on eye dominance under normal conditions, during simulated weightlessness and in schizophrenic patients.
METHODS:
Data of 41 healthy subjects, 14 volunteers, exposed to dry immersion (DI) and 19 schizophrenic patients were analyzed. Healthy subjects were right-handed males with right (RE) and left (LE) eye dominance, and patients had RE dominance. 2 modifications of antisaccadic task were used. In A1 task fixation period was 800-1000 ms, and in A2 task – 1200-1400 ms. EEG was recorded from 19 sites. Mean amplitude of slow cortical negative potentials (SN) time-locked to peripheral stimulus (PS) onset was evaluated. 600 ms epoch before PS was used for quantitative evaluation of SN amplitude in A1 task, and 1000 ms - in A2 task. Statistics comprised MANOVA and t-test. Correlations between SN amplitudes and PANSS scales were analyzed in schizophrenic patients.
RESULTS:
The saccade characteristics did not depend on task and experimental conditions in healthy RE subjects. In LE subjects percent of errors was lower in A2 task than in A1 one, and increase of errors and saccade latencies was revealed after exposure to DI. Patients performed A2 task better than A1 one, but they exhibited delays in performance of correct saccades and larger number of errors in both tasks compared to healthy subjects. RE subjects demonstrated high level of frontal activation before antisaccades in both tasks. Reduced SN amplitude in frontal region was revealed in LE subjects. The most pronounced decline of SN amplitude in frontal regions was found in patients. Higher PANSS values corresponded to lower amplitude of SN, and maximal number of correlations was found for Fz and F3 sites. Predominant left hemisphere activation was observed during the last 200 ms before peripheral cue in all groups. Changes in cortical activity after DI were similar in RE and LE groups: SN amplitude decreased, and foci of negativity shifted to the right hemisphere.
CONCLUSIONS:
The obtained results demonstrate the independence of basic hemisphere specialization from eyedness, support the neurodevelopmental model of cerebral lateralization, and corroborate the important role of frontal disorders in genesis of schizophrenia.
PUBLICATION:
A.V.Kirenskaya, E.S. Tomilovskaya, V.Yu.Novototsky-Vlasov, I.B.Kozlovskaya. The effects of simulated microgravity on characteristics of slow presaccadic potentials. Human physiology, 2006, v. 32, N 2, pp. 131-139.; A.Kirenskaya, V. Novototsky-Vlasov, V. Myamlin, I.Ushakova. The study of disturbances of cortical
processes related to saccadic generation in schizophrenic patients. Int. Congress “Progress in Neuroscience for medicine and psychology”, Sudak, Crimea, Ukrain, 2005, pp. 90-91.; A.Kirenskaya, V. Myamlin, V. Novototsky-Vlasov, E. Tomilovskaya, I.Ushakova, I.B.Kozlovskaya. Cortical potentials preceeding antisaccades in healthy subjects, schizophrenic patients and after simulated weightlessness. Int. J. Psychophysiol., 2006, v.61, N3, P. 346.
|
Secondary author(s):
| Tomilovskaya, E., Kirenskaya, A., Novototsky-Vlasov, V. Y., Myamlin, V., Gallyamova, N. R.
|
Reference:
| Kozlovskaya, I., Tomilovskaya, E., Kirenskaya, A., Novototsky-Vlasov, V. Y., Myamlin, V., & Gallyamova, N. R. (2008). Comparative study of brain processes related to microgravity-induced and clinical oculomotor disturbances in subjects with the right and left eye dominance. In Aquém e além do cérebro. Behind and beyond the brain. Proceedings of the 7th Symposium of Fundação Bial. Porto: Fundação Bial.
|
The contingent negative variation laterality and dynamics in antisaccade task in normal and unmedicated schizophrenic subjects