A new device for monitoring early motor development: prenatal nicotine-induced changes.

A new type of activity meter has been designed especially for young rats. It consists of a warmed platform for the animal, a TV camera with monitor and a microprocessor. The TV camera detects the animal as a black figure on a light background. This picture is digitalized and stored in a Z80 microprocessor. Every 200 msec a new image is compared to the foregoing one. The total number of black points that are changing from black to white and vice versa provides a measure for motor activity of the animal. Prenatally nicotine-treated rat pups were tested on the activity meter. The developmental pattern of motor activity was different for male and female pups. Motor activity of nicotine-treated male pups differed significantly from controls at postnatal days 7 and 15 while this drug effect was not seen in females.