[Spindle-shaped cortical potentials during rabbit ontogeny].

Studies have been made on total spike activity in the cortex of 3 of 41 days old rabbits. It was shown that in newborn rabbits periodic spindle-like outbursts of high amplitude potentials present typical primary activity of the cortex. This form of activity may be observed both in resting and moving animals. After eye opening, especially beginning from the 16th day, periodic outbursts of high amplitude potentials are observed only during behavioural manifestations of sleep or under nembutal narcosis. During maturation of the cortex, periodic pattern and frequency composition of the outbursts do not undergo any significant changes. Probably, "sleeping spindles" in mature brain are genetically associated with the primary spindle-like activity in the immature cortex, being produced by the same mechanism as the primary spindles in immature cortex.