Interhemispheric interaction and cause of hindrance during handedness activity: An electro-physiological evidence

Interhemispheric dominance is an established yet paradoxical concept in neuroscience according to the activity of the body part and nature of the human physiology. The objective of the present study was to compare the various parameters and topography of EEG brain signals between left handed and right handed individuals during primary sensorimotor activity tasks and to find out the cause of hindrance, when a person tries to perform a job usually done by the dominant arm, with the other. Left and right handed normal individuals were asked to write words, which are new and novel to both the categories. These were formulated and presented in a manner such that memory does not play a significant role during the task execution. Subjects were instructed to write the words by using each hand successively in two experimental sessions. The EEG signals were recorded with 16-channel electrodes and were analyzed in time as well as frequency domain paradigm. Results indicate a significant reduction of alpha and beta power over parieto-temporal as well as fronto-central regions in each writing session. It is speculated that brain structures, which have been associated with sensory-motor task get desynchronized during the task execution and the hindrance effect is generated due to the neuronal coupling of both hemisphere in human brain.