The comparative estimation of coherent connections (СС) and spectral power (SP) of the main EEG rhythms in 30 subjects (left-handers with left dominant) was performed using emotional Stroop-test. Subjects were divided into 3 groups: monocular group with left (dominant) opened eye, monocular group with right (nondominant) opened eye and binocular group.

During binocular viewing zonal increase of beta rhythm power was observed that may be evidence of cognitive control of the accuracy of the assignment. There is no prevalence of high-frequency oscillations in some of the hemispheres that could be connected with more bilateral presentation of verbal functions in the left-handers comparing with the right-handers. CC was significantly increased in the central-parietal pairs of both hemispheres, indicating growth of synchronization in left hemisphere structures involved in the automatic analysis, and in the right hemisphere – which is involved in the controlled analysis.

During perception through dominant left eye CC increased in the range of theta-, alpha, beta rhythms in the central-parietal pair and theta range in the frontal-temporal pair of the left hemisphere, high-frequency beta range in the parietal-occipital pair of right hemisphere. Grows of SP theta rhythm in central-parietal areas and SP beta rhythm that is largely right-localized that is contralateral to the opened left eye, was observed. As far as right hemisphere is involved in the tasks that needed attention we suggests that growth in sub-bands of beta rhythm in the right hemisphere in subjects that performed tasks with opened dominant left eye can be associated with concentration of attention on the problem of recognition of color and relative neglect of the emotional context of stimuli.

During perception through nondominant right eye generalized growth of theta rhythm is accompanied by decreased activity of alpha rhythm in the right central, parietal, posterior temporal areas, increase local SP beta range in the right prefrontal and parietal leads. CC increased in the high-frequency range of beta rhythm in frontal-central area of the left hemisphere, of alpha band in central-parietal area of the left hemisphere, of frontal and central area of the right hemisphere. CC decreased in the range of theta- and beta rhythm in the prefrontal-frontal and frontal-central areas of the right hemisphere. High-frequency oscillations in the EEG, which include beta and gamma bands, are interpreted in literature as a correlate of a variety of cognitive processes, which require a high level of attention. Growth of SP beta rhythm in the frontal areas of the brain during the test with emotional words in all groups reflects attention to a new task. Emotional Stroop test requires development of an effective strategy to solve the basic problem (text color identification) and inhibition of brain regions that are automatically included in the analysis of the semantic meaning of words, the prefrontal cortex assumes these processes, which serves as the central executive. During binocular vision of emotional words, symmetric changes of coherence and spectral power in both hemispheres were observed, so under these conditions both hemispheres are included equal in the analysis. The task with emotional words during their presentation in non dominant eye in righthanders accompanied by greater brain activation and emotional stress compared with a group that viewed through dominant eye. During usage of dominant eye subjects were able to focus on the task more effectively that was indicated by growth of beta rhythm in contralateral to the opened eye hemisphere and fewer number of errors.

Keywords: Stroop-test, dominant eye, left-handers, monocular vision, emotional verbal stimuli, coherence

Full text: PDF (Ukr)

1. 1. Dobrohotova T, Brahina N. Left-handers. Kniga: 1994. 231.
2. 2. Rasomagina M, Kravchenko V. Electric activity of brain during monocular presentations of verbal stimuli in Emotional Stroop-task. Vistnyk of Taras Shevchenko National University of Kyiv. Problems of physiological functions regulations. 2013;16:37-41.
3. 3. Rassomagina M, Kravchenko V, Makarchuk M. Electrophysiological correlates of verbal stimuli analysis during their monocular perception. Vistnyk of Lviv University. Biological series. 2014;65: 348-354.
4. 4. Abbassi E, Kahlaoui K. Processing the emotions in words: The complementary contributions of the left and right hemispheres. Psychonomic Society. 2011;11(3):372-85. doi.org/10.3758/s13415-011-0034-1
5. 5. Brad N, Hamilton D. Monocular-binocular coordination vs.hand-cyc dominance as a factor in reading performance. American Journal of Optometry and Archives of the Amen'can Academy of Uptometry. 1971;48:123-129. doi.org/10.1097/00006324-197102000-00005
6. 6. Buzsaki G, Wang X. Mechanism of Gamma oscillation. Annual Review of Neuroscience. 2012;35:203-235. doi.org/10.1146/annurev-neuro-062111-150444
7. 7. Kensinger E, Corkin S. Memory enhancement for emotional words: Are emotional words more vividly remembered than neutral words? Memory & Cognition. 2003;31:1169-1180.
8. 8. Khan A, Crawford J. Ocular dominance reverses as a function of horizontal gaze angle. Vision Res. 2001;41(14):1743-1748.doi.org/10.1016/S0042-6989(01)00079-7
9. 9. Koivisto M. Time course of semantic activation in the cerebral hemispheres. Neuropsychologia. 1997;35:497-504. doi.org/10.1016/S0028-3932(96)00100-5
10. 10. Rammsayer T, Stahl J. Extraversion-related differences in response organization: Evidence from lateralized readiness potentials. Biological Psychology. 2004; 66:35-49. doi.org/10.1016/j.biopsycho.2003.08.003
11. 11. Ranganath C, D'Esposito M, DeGutis J. Category-specific modulation of inferior temporal activity during working memory encoding and maintenance. Cogn Brain Res. 2004;20(1):37-45. doi.org/10.1016/j.cogbrainres.2003.11.017
12. 12. Rassomagina M, Kravchenko V, Makarchuk M. Electrophysiological correlates of monocular dominant eye perception of verbal stimuli in emotional Stroop-test. Lietuvos mokslų akademija. Biolojia. 2014;60(2):79-95.
13. 13. Summerfield C, Mangels J. Coherent thetaband EEG activity predicts item-context binding during encoding. Neuroimage. 2005;24:692-703. doi.org/10.1016/j.neuroimage.2004.09.012