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Interhemispheric cooperation

In our first study on the interhemispheric transmission, electrophysiological estimates of interhemispheric transmission time (IHTT) were investigated. The major point of interest was the relation between IHTT and direction of transmission of visual information (to and from the hemisphere specialized in processing of that information). IHTTs were shorter when the information was transferred from the hemisphere non-specialized to the specialized one than in the opposite direction.

The aim of the next study was to test whether memory processes depend on which hemisphere initiates processing of visual information. Memory-related modulation of ERPs was found for frontal recording sites. The late ERPs repetition effect, however, was present in the ERPs data only in case of the direct stimulation of the competent hemisphere, i. e., the LH for words and RH for Kanji. Stimulation of the incompetent hemisphere resulted in lack of the repetition effect in either hemisphere. It seems that the critical factor for emergence of the ERPs repetition effects that may be related to the encoding of new and repeated items is the fact which hemisphere initiated processing of visual information. If it was a competent hemisphere, the ERPs repetition effect was observed in both hemispheres. If it was an incompetent hemisphere, there was no effect in either hemisphere. In case of direct stimulation of one hemisphere the information conveyed by a laterally presented stimulus had to be transferred to the alternate hemisphere indirectly via interhemispheric commissures. The interhemispheric transfer of information is likely to result, however, both in time-delays and in degradation of transmitted information. The latter is apparently the case in our study: the transfer of visual information from the incompetent hemisphere to the competent one has caused such a degradation of transmitted information that it was insufficient to adequately initiate memory-related modulation of the electrical activity in the competent hemisphere.

Nowicka A., Tacikowski P. Transcallosal transfer of information and functional assymetry of human brain. Laterality, 16(1): 35-74, 2011

Marchewka A., Nowicka A. Emotionally negative stimuli. are resistant  to repetiton priming.  Acta Neurobiologiae Experimentalis. 67: 83-92, 2007  

Nowicka A, Szatkowska I. Memory-induced modulation of event-related potentials in frontal cortex of human subjects: a divided visual field study. Neuroscience Letters, 359: 171-174, 2004

Nowicka A, Fersten E. Sex-related differences in interhemispheric transmission time in the human brain. NeuroReport, 12: 4171-4175, 2001

Nowicka A, Grabowska A, Fersten E. Interhemispheric transmission of information and functional asymmetry of the human brain. Neuropsychologia, 34: 147-151, 1996

Nencki Institute of Experimental Biology (c) 2017