Fast updating feedback from piriform cortex to the olfactory bulb relays multimodal reward contingency signals during rule-reversal.

While animals readily adjust their behavior to adapt to relevant changes in the environment, the neural pathways enabling these changes remain largely unknown. Here, using multiphoton imaging, we investigated whether feedback from the piriform cortex to the olfactory bulb supports such behavioral flexibility. To this end, we engaged head-fixed mice in a multimodal rule-reversal task guided by olfactory and auditory cues. Both odor and, surprisingly, the sound cues triggered cortical bulbar feedback responses which preceded the behavioral report. Responses to the same sensory cue were strongly modulated upon changes in stimulus-reward contingency (rule reversals). The re-shaping of individual bouton responses occurred within seconds of the rule-reversal events and was correlated with changes in the behavior. Optogenetic perturbation of cortical feedback within the bulb disrupted the behavioral performance. Our results indicate that the piriform-to-olfactory bulb feedback carries reward contingency signals and is rapidly re-formatted according to changes in the behavioral context.

Depression beliefs, treatment preference, and outcomes in a randomized trial for major depressive disorder.

Previous studies suggest that individual preferences for medication- or psychotherapy-based treatments for depression may affect outcomes in clinical trials that compare these two forms of treatment. We assessed patients' beliefs about the causes of their depression, their preferred treatment, and strength of that preference in 80 patients participating in a 12-week clinical trial evaluating neuroimaging predictors of response to cognitive behavior therapy (CBT) or escitalopram. Forty-five patients expressed a preference for one of the 2 treatments, but being matched to preference did not influence remission or completion rates. Medication-preferring patients were more likely to terminate the trial early, regardless of treatment received. CBT-preferring patients rarely endorsed unknown causes for their depression, and medication-preferring patients were highly unlikely to identify pessimistic attitudes as a source of their depression. Among patients willing to be randomized to treatment, preference does not appear to strongly influence outcome. Specific preferences for CBT or medication may reflect differing conceptualizations about depressive illness, knowledge of which may enhance treatment retention and efficacy.

Do decisions shape preference? Evidence from blind choice.

Psychologists have long asserted that making a choice changes a person's preferences. Recently, critics of this view have argued that choosing simply reveals preexisting preferences, and that all studies claiming that choice shapes preferences suffer from a fundamental methodological flaw. Here we address this question directly by dissociating preexisting preferences from decision making. We studied participants who rated different vacation destinations both before and after making a blind choice that could not be guided by preexisting preferences. As an additional control, we elicited ratings in a condition in which a computer made the decision for the participants. We found that preferences were altered after participants made a blind choice, but not after a computer dictated the decision. The results suggest that just as preferences form choices, choices shape preferences.