[Reaching behavior of rats during realization of a lateralized motor food skill]

Adult Wistar rats were trained to obtain food pellets from a narrow horizontal tube with a preferred forepaw. The feeder was equipped with five photoelectric sensors with 5-mm spacing. The following parameters were recorded: total number of movements performed for a given task, amplitude (depth) of each movement, number of anticipatory movements performed with different amplitudes, and amplitude of a successful movement. It was shown that in rats with good skill acquisition, a successful food extraction was preceded by a series of differently organized sequence of preliminary movements. In some rats, such a series consisted of initial non-deep attempts followed by movements with high amplitude, whereas in other animals, it was represented, mainly, by deep attempts. Both groups of animals terminated the series by grasping and extracting food from a long distance. It is suggested that the observed organizations of the lateralized food-getting behavior of rats under the given experimental conditions represent fixed (stereotyped) action patterns.