Roll-to-roll solvent annealing of printed P3HT : ICA devices.

Currently, large-scale roll-to-roll production of printed organic photovoltaics (OPVs) involves high temperature annealing steps that are not compatible with thermally sensitive substrates, such as coated fabrics. In particular, the processing temperatures needed to produce the required crystalline ordering in the printed films are typically above the deformation and melting-points of these substrates. In this paper we investigate the use of local solvent recrystallisation (solvent annealing) on the roll-to-roll scale as a method for avoiding high-temperature thermal annealing.

Dynamic shaping of dopamine signals during probabilistic Pavlovian conditioning.

Cue- and reward-evoked phasic dopamine activity during Pavlovian and operant conditioning paradigms is well correlated with reward-prediction errors from formal reinforcement learning models, which feature teaching signals in the form of discrepancies between actual and expected reward outcomes. Additionally, in learning tasks where conditioned cues probabilistically predict rewards, dopamine neurons show sustained cue-evoked responses that are correlated with the variance of reward and are maximal to cues predicting rewards with a probability of 0.5.

Phasic dopamine release in the nucleus accumbens in response to pro-social 50 kHz ultrasonic vocalizations in rats.

Rats emit ultrasonic vocalizations (USVs) that are thought to serve as situation-dependent affective signals and accomplish important communicative functions. In appetitive situations, rats produce 50 kHz USVs, whereas 22 kHz USVs occur in aversive situations. Reception of 50 kHz USVs induces social approach behavior, while 22 kHz USVs lead to freezing behavior.

Phasic dopamine release in the rat nucleus accumbens symmetrically encodes a reward prediction error term.

Making predictions about the rewards associated with environmental stimuli and updating those predictions through feedback is an essential aspect of adaptive behavior. Theorists have argued that dopamine encodes a reward prediction error (RPE) signal that is used in such a reinforcement learning process. Recent work with fMRI has demonstrated that the BOLD signal in dopaminergic target areas meets both necessary and sufficient conditions of an axiomatic model of the RPE hypothesis.

Altered risk-based decision making following adolescent alcohol use results from an imbalance in reinforcement learning in rats.

Alcohol use during adolescence has profound and enduring consequences on decision-making under risk. However, the fundamental psychological processes underlying these changes are unknown. Here, we show that alcohol use produces over-fast learning for better-than-expected, but not worse-than-expected, outcomes without altering subjective reward valuation.

Chronic microsensors for longitudinal, subsecond dopamine detection in behaving animals.

Neurotransmission operates on a millisecond timescale but is changed by normal experience or neuropathology over days to months. Despite the importance of long-term neurotransmitter dynamics, no technique exists to track these changes in a subject from day to day over extended periods of time. Here we describe and characterize a microsensor that can detect the neurotransmitter dopamine with subsecond temporal resolution over months in vivo in rats and mice.