Fig. 13.

Trial-level effects under the task NoRew_Neg from one subject. (a) Effect estimates are shown at two contralateral regions, left (upper row) and right (lower row) ventral striatum. Black segments indicate one standard error, and the colors code the four different AR models (OLS, AR(1), AR(2) and ARMA(1,1)) for the residuals in the GLS model (1). Only 35 trials (out of 48) were successfully completed by the subject. Despite substantial amount of cross-trial variability, some consistent extent of synchronization was revealed across all the four models and all the five contralateral region pairs (only one pair, ventral striatum, shown here). (b) Effect estimates (AR2L, black) at left ventral striatum were obtained with AR effects modeled as second-order lagged effects of the EPI time series in the model (21) as implemented in Westfall et al. (2017). The same AR(2) results from (a) are shown (AR2, iris blue) as a comparison. The impact of incorporating lagged effects in the model was quite evident with both effect estimates and their precision substantially higher at some trials.