Summation and adaptation in stimulation of the motor cortex in adult and newborn animals

Summary

In rabbits and their progeny an investigation was made of summation and adaptation of the neurones of the motor cortex; unipolar stimulation was used, and the muscular response recorded. Two types of summation curves were found: “exponential” and “Y-shaped,”, and were related to the “direct” and “indirect” summation of stimulation. In adults, “Y-shaped” summation curves were more frequent, whereas in rabbits aged 24 h “exponential” curves preponderted. We found very little capacity for adaptation at any age.