SpeakerAllison Shapiro, UCSB
Date and LocationFriday June 07, 2019 12:00pm
Two fundamental goals of decision making are to select actions that maximize rewards while minimizing costs and to have strong confidence in the accuracy of a judgment. Neural signatures of these two forms of value: the subjective value of choice alternatives (SV) and the value of the judgment (confidence), have been observed in ventromedial prefrontal cortex (vmPFC). However, the relationship between these dual value signals and their relative time courses are unknown. Furthermore, there are often several ways that one can obtain a desired reward, each entailing its own costs. Previous research investigated the neural representations of many types of decision costs with the notable exclusion one evolutionarily significant expense: cardiovascular effort. It remains unclear how physical costs, such as pain and exertion are transformed into value information to guide decision making and the extent to which this process is domain-specific versus domain-general. To test this, we conducted two fMRI experiments in which participants performed a two-phase ApAv task with mixed-outcomes of monetary rewards paired with costs painful shock stimuli and cardiovascular exercise on a stationary bike. Neural responses were measured during offer valuation (offer phase) and choice valuation (commit phase) and analyzed with respect to observed decision outcomes, costs, and model-estimated SV and confidence. Our results reveal complementary representations in vmPFC during value-based decision making that temporally dissociate such that offer valuation (SV) emerges before decision valuation (confidence). Conversely, activation of the cognitive control network, including within lateral prefrontal cortex (lPFC) and dorsal anterior cingulate cortex (dACC) was associated with ambivalence during both decision phases. None of these signals differed in magnitude between the pain and effort conditions, consistent with shared neural faculties for processing both types of decision costs. However, inspection of voxel response patterns within those faculties revealed representational dissimilarity between pain and effort costs, indicating that cost-domain-specific information is encoded throughout the decision making process. Within vmPFC in particular, the availability of cost-specific information over the course of a decision suggested qualitatively different decision processes under conditions of confidence and ambivalence.