Strength-duration properties of single units driven by electrical stimulation of the lateral hypothalamus in rats

Cathodal strength-duration functions were measured for 27 single units which were driven by electrical stimulation of the lateral hypothalamus. The distribution of chronaxies of these units showed four clusters at about 0.1, 0.25, 0.4 and 0.5 msec. These chronaxies are not fundamentally different from those previously reported for peripheral nerve. Two units fired repetitively during a long-duration stimulation pulse. Anodal strengitation. The data are discussed with reference to behaviorally determith duration properties were obtained from 14 units. Four units were not excited by anodal pulses of any strength or duration, four were excited during an anodal pulse (anode-make excitation) but not at the termination of the pulse (anode-break excitation), and six showed both anode-make and anode-break excitation. The data are discussed with reference to behaviorally determined strength-duration functions for brain stimulation reward.