Stimulation of the mesencephalic locomotor region inhibits the discharge of neurons in the superficial laminae of the dorsal horn of cats

In decerebrate cats, we found that stimulation of the mesencephalic locomot or region (MLR) attenuated the responses of neurons in the superficial lami nae of the dorsal horn to thin fiber muscle afferent input. The attenuation appeared to be more effective for group III afferent input than for group IV. These findings may shed light on the interaction between central comman d, (i.e. the MLR) and the muscle reflex, mechanisms which both contribute t o the cardiovascular responses to exercise. (C) 2000 Elsevier Science Irela nd Ltd. Ail rights reserved.