Training and quantifying voluntary plantar-flexor movements of rats

The present paper describes a rat preparation that was designed to produce voluntary plantar-flexor movements under precise constraints and to record various movement parameters. Sixteen rats were trained with operant conditioning techniques and food rewards to voluntarily and repeatedly enter a vertical tube, insert its head into a ring, lift the ring until its nose interrupted an infrared detector, and then lower the ring. The apparatus and training procedures were computer automated. Results demonstrate the ability of this preparation to precisely control and record the dynamics of a repetitive lifting and lowering movement of the lower limbs applicable to studies of muscle adaptation or injury.