[Frequency of self stimulation in cats when two parameters are changed simultaneously]

In cats, with electrodes implanted in the lateral hypothalamus a dependence was obtained of self-stimulation frequency (SSF) on paired changes of current strength and each of other stimulation parameters-duration, pulse duration and frequency. In some cases these parameters may independently affect SSF but generally they are in interaction. For stimulation with electrodes located at the level of the hypothalamic ventromedial nucleus, two-peak dependences of SSF on the current strength and the duration of stimulation pulses were obtained. An attempt to describe empirical response surfaces with a regression equation with members of not higher than 4-th order led to an insufficient accuracy of approximation as compared to the results obtained previously on rats. The cause of this insufficiency as well as two-peacked SSF dependencies are discussed in terms of morphofunctional heterogeneity of activated brain structures.