However, note that conjunction inference via the minimum t statistic is valid even when the conjoined contrasts are not independent

( Nichols et al., 2005). We also used the right-hemisphere portion of the mask of nucleus accumbens (right being the side on which we have previously observed stronger RPE activity; e.g., Daw et al., 2006b and Wittmann et al., 2008) to define the ROI selleck screening library for two analyses conducted with the MarsBaR ROI toolbox (Brett et al., 2002). First, average activity from the region was extracted and subjected to the same analysis as described above, to produce Figure 3F. Second, the activity from the region was subject to a second regression analysis using a different design, which tagged the first-stage onset of each trial with an impulse regressor of one of five types: switches (trials on which the opposite first-stage choice from the one on the previous trial was made) and stays (four types of events modeling all combinations of the factors reward versus nonreward and common versus rare transition in the previous trial). An additional nuisance BMN 673 research buy regressor was included at the time of outcomes. Per-subject effect sizes for the four stay regressors were subject to a 2 × 2 repeated-measure ANOVA, and, additionally, the value for each subject of the contrast measuring the interaction

of the two factors ([reward/common minus nonreward/common] minus [reward/rare minus nonreward/rare]) was correlated with the weight given to model-based values (the estimated parameter w) from the behavioral fit. The authors are grateful to Yael Niv, Dylan Simon, Aaron Bornstein, Seth

Madlon-Kay, Bianca Wittmann, Bernard Balleine, Jan Gläscher, and John O’Doherty for helpful conversations and advice. This work was in part supported by a McKnight Scholar Award (N.D.), NIMH grant 1R01MH087882-01, part of the CRCNS program (N.D.), a NARSAD Young Investigator Award (N.D.), the Gatsby Charitable Foundation (P.D.), and a Wellcome Trust Programme Grant to R.J.D. “
“Deciphering the neural code has triggered many investigations Adenosine triphosphate and debates over the past decades. Both firing rate and temporally governed spike patterns of individual neurons or neuronal ensembles have been shown to provide means to encode information in brain circuits. In hippocampal principal cells, the distribution of firing rate across an environment is skewed such that each cell, referred to as a “place cell,” tends to fire in a specific location (spatial firing field or “place field”), leading to the classical view that hippocampal place maps represent space in the form of a rate code. Hippocampal place maps, however, are flexible: changing environments and task demands lead to “remapping” phenomena in which the neural code is altered to mirror the animal’s experience.

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