TY - JOUR
T1 - Dorsomedial striatum lesions affect adjustment to reward uncertainty, but not to reward devaluation or omission
AU - Torres, Carmen
AU - Glueck, Amanda C.
AU - Conrad, Shannon E.
AU - Morón, Ignacio
AU - Papini, Mauricio R.
N1 - Publisher Copyright:
© 2016 IBRO
PY - 2016/9/22
Y1 - 2016/9/22
N2 - The dorsomedial striatum (DMS) has been implicated in the acquisition of reward representations, a proposal leading to the hypothesis that it should play a role in situations involving reward loss. We report the results of an experiment in which the effects of DMS excitotoxic lesions were tested in consummatory successive negative contrast (reward devaluation), autoshaping training with partial vs. continuous reinforcement (reward uncertainty), and appetitive extinction (reward omission). Animals with DMS lesions exhibited reduced lever pressing responding, but enhanced goal entries, during partial reinforcement training in autoshaping. However, they showed normal negative contrast, acquisition under continuous reinforcement (CR), appetitive extinction, and response facilitation in early extinction trials. Open-field testing also indicated normal motor behavior. Thus, DMS lesions selectively affected the behavioral adjustment to a situation involving reward uncertainty, producing a behavioral reorganization according to which goal tracking (goal entries) became predominant at the expense of sign tracking (lever pressing). This pattern of results shows that the function of the DMS in situations involving reward loss is not general, but restricted to reward uncertainty. We suggest that a nonassociative, drive-related process induced by reward uncertainty requires normal output from DMS neurons.
AB - The dorsomedial striatum (DMS) has been implicated in the acquisition of reward representations, a proposal leading to the hypothesis that it should play a role in situations involving reward loss. We report the results of an experiment in which the effects of DMS excitotoxic lesions were tested in consummatory successive negative contrast (reward devaluation), autoshaping training with partial vs. continuous reinforcement (reward uncertainty), and appetitive extinction (reward omission). Animals with DMS lesions exhibited reduced lever pressing responding, but enhanced goal entries, during partial reinforcement training in autoshaping. However, they showed normal negative contrast, acquisition under continuous reinforcement (CR), appetitive extinction, and response facilitation in early extinction trials. Open-field testing also indicated normal motor behavior. Thus, DMS lesions selectively affected the behavioral adjustment to a situation involving reward uncertainty, producing a behavioral reorganization according to which goal tracking (goal entries) became predominant at the expense of sign tracking (lever pressing). This pattern of results shows that the function of the DMS in situations involving reward loss is not general, but restricted to reward uncertainty. We suggest that a nonassociative, drive-related process induced by reward uncertainty requires normal output from DMS neurons.
KW - extinction spike
KW - partial reinforcement
KW - reward devaluation
KW - reward omission
KW - reward uncertainty
KW - successive negative contrast
UR - http://www.scopus.com/inward/record.url?scp=84977627327&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84977627327&partnerID=8YFLogxK
U2 - 10.1016/j.neuroscience.2016.06.041
DO - 10.1016/j.neuroscience.2016.06.041
M3 - Article
C2 - 27365171
AN - SCOPUS:84977627327
SN - 0306-4522
VL - 332
SP - 13
EP - 25
JO - Neuroscience
JF - Neuroscience
ER -