Operant reflex-related neuronal activity in the tectum of the superior colliculus and mesencephalic reticular formation of the cat

We tried to answer the question to what extent neurons in the tectum of the superior colliculus (SC) of the cat and in regions of the mesencephalic reticular formation (MRF) localized more ventrally are involved in the control of movements of the limbs. The impulse activity of neurons of the above-mentioned structures was recorded in animals performing targeted operated food-procuring movements by their forelimbs (pressing the pedal). As was found, neurons with impulse reactions correlating with forelimb movements are rather numerous in the SC and adjacent MRF, and there are several groups of neurons, whose impulse responses reached their maxima within different phases of the movements. These were neurons with peaks of the discharge frequency coinciding with the target-reaching movement, with the moment of touching the pedal, with pressing the pedal, and with the development of the muscle force counteracting the forced withdrawal of the limb toward the initial position. Such specific patterns of the responses of different neurons of the SC and neighboring MRF are indicative of a rather specific involvement of the above structures in the control of forelimb movements in cats. Neirofiziologiya/Neurophysiology, Vol. 39, No. 3, pp. 245–254, May–June, 2007.