The opportunity for alternative reinforcement shortens bout length in BALB/c C57BL/6 mice

Abstract

A recent mathematical model has been suggested to partition response rate into two independent components that are estimated through a log survivor analysis of inter-response times. One component is thought to tap motivational and the other motor components of behavior. The robustness of this phenomenon was tested in a new species, with a novel approach to maintaining high rate behavior, and different approaches to manipulated motivational and motor components. BALB/c and C57BL/6 mice were used due to their differences in behavioral measures. A percentile schedule was used to reinforce a high rate of behavior (Mult RI 60, 10:0.5). BALB/c mice nose poked at a higher rate than C57BL/6 mice, but responded similarly to the different behavioral interventions. The addition of a running wheel and food deprivation level significantly decreased total nose pokes. Adding a running wheel increased bout initiation rate, but decreased bout length. Taking the animals off food restriction decreased bout initiation rate. Light cycle changes did not affect nose poking. Pearson correlations support the idea of the behavioral divergence of the two strains.