[Asymmetry of interhemispheric transcallosal responses in cat ontogeny]

In acute experiments on immobilized by myorelaxants kittens (1-21 days old) and adult cats, studies have been made on the development of functional interhemispheric asymmetry (FIA) of transcallosal responses (TCR) in the motor cortex. Individual asymmetry during ontogenesis is transformed into specific one. With respect to both components of TCR,, asymmetry in kittens was of the individual character. In adult cats, specific (left hemispheric) asymmetry was found with respect to positive phase of the responses, and individual FIA - with respect to negative phase. During postnatal phase of the responses, the degree of asymmetry of the positive components of TCR is increased, whereas that of the negative ones - is decreased. Kittens, similar to adult cats, exhibit four types of FIA: qualitative, quantitative, topographic, quantitatively topographic. Ontogenetic changes in the properties of asymmetry were revealed. FIA of TCR exhibited: 1 - partial domination; 2 - bilateral origin; 3 - dynamism (in kittens) and relative stability (in cats). Maturation of FIA during postnatal ontogenesis is suggested.