An Operant Conditioning Task to Assess the Choice between Wheel Running and Palatable Food in Mice.
BIO-PROTOCOL. 2019-01-01; 9(19):
Read on PubMed
Redon B(1)(2), Hurel I(1)(2), Marsicano G(1)(2), Chaouloff F(1)(2).
(1)Inserm U1215, Neurocentre Magendie, Team Endocannabinoids & NeuroAdaptation, Bordeaux F33077, France.
(2)Université de Bordeaux, Bordeaux-F33077, France.
Wheel running, especially in the homecage, has been widely used to study the
neurobiology of exercise because animal tends to use it voluntarily. However, as
for each reward, its consumption (in the present case, running performance) does
not specifically provide information on its incentive value, i.e., the extent to
which animals are motivated to run independently from their consumption of that
reward. This is a major drawback, especially when focusing on the neurobiology
governing the pathological imbalances between exercise and e.g., feeding
(obesity, anorexia nervosa). Yet, few studies have shown that operant
conditioning wherein wheel-running is used as a reinforcer that can be “consumed”
after nose-poking or lever-pressing allows to distinguish motivation from
consumption. Thus, nose-poking or lever-pressing under a progressive ratio
schedule of reinforcement in animals trained under fixed ratio reinforcement
schedules provides, through the so-called breakpoint, an index of running
motivation. As compared to wheel-running, numerous studies have used food as a
reinforcer, which helped to uncover the neurobiology of feeding. However, to our
knowledge, there is no paradigm allowing the assessment of the choice between
running and feeding when presented in concurrence, with the possibility to
measure a priori the motivation for each reward. Herein, we describe a protocol
that first permits to measure the drive for each of these two rewards before it
allows to measure the preference for one over the other in a reward choice
setting. This paradigm could help to better characterize the neurobiology
underlying pathological imbalances between physical activity and feeding, which
is the core feature of eating disorders.
Copyright © 2019 The Authors; exclusive licensee Bio-protocol LLC.