Subjective reward magnitude of medial forebrain stimulation as a function of train duration and pulse frequency.

Abstract

The growth of the subjective reward magnitude of medial forebrain bundle stimulation in the rat (Sprague-Dawley) as a function of train duration and pulse frequency was measured in 2 ways: (a) a titration method, which used differences in rate of reward on 2 levers to compensate for differences in the magnitude of the rewards; and (b) a direct method, in which the ratio of the reward magnitudes at the 2 levers was assumed to be given by the ratio of times spent on each lever. The results of the 2 methods agree. Reward magnitude grows as approximately a power function of train duration up to train durations of about 1 s, then declines somewhat over the interval from 2-20 s. The exponent of growth varies from 0.4 to 2.3. With stronger stimulation (higher pulse frequency), peak reward magnitude is bigger, but the saturating train duration is approximately the same.

The central extended amygdala network as a proposed circuit underlying reward valuation

“…That is not to say that the neural computation of utility has been ignored. Within the field of self-stimulation alone there is a rich and growing literature (Waraczynski et al, 1987;Leon and Gallistel, 1992;Mark and Gallistel, 1993;Gallistel, 1994;Simmons and Gallistel, 1994;Shizgal, 1997;Leon and Gallistel, 1998;Sonnenschein et al, 2003). What has been relatively neglected is the discovery and elucidation of the neuroanatomical circuitry that most likely lies between stimulus detection and the translation of motivation into action, a system that computes the value of present stimuli.…”

Extracting meaning from past affective experiences: The importance of peaks, ends, and specific emotions

“…Duration neglect in rats also applies to pleasurable experiences, like rewarding brain stimulation (Shizgal, 1997). Mark and Gallistel (1993) demonstrated that rats exhibit comparable subjective rewards to medial forebrain stimulation, regardless of stimulus duration, as long as the stimulation exceeds 1 second. Beyond this length, rats sought out activities that triggered the brain stimulation regardless of reward duration.…”

Optimal indolence: a normative microscopic approach to work and leisure

“…This is assumed to have a subjective worth, or microscopic utility (to distinguish it from the macroscopic utility described in [18 -23]) called the reward intensity (RI, in arbitrary units). The transformation from objective to subjective worth has been previously determined [42][43][44][45][46][47]. The ratio of the RI to the price is called the pay-off.…”