Knowledge by omission: the significance of omissions in the 5-choice serial reaction time task.

Rationale: The 5-choice serial reaction time task (5-CSRTT) is commonly used to assess attention in rodents. Manipulation of this task by decreasing the light stimulus duration is often used to probe attentional capacity and causes a decrease in accuracy and an increase in omissions. However, although a decrease in response accuracy is commonly interpreted as a decrease in attention, it is more difficult to interpret an increase in omissions in terms of attentional performance.

Large-scale brain correlates of sweet versus cocaine reward in rats.

Cocaine induces many supranormal changes in neuronal activity in the brain, notably in learning- and reward-related regions, in comparison with nondrug rewards-a difference that is thought to contribute to its relatively high addictive potential. However, when facing a choice between cocaine and a nondrug reward (e.g.

Cocaine falls into oblivion during volitional initiation of choice trials.

When facing a choice, most animals quit drugs in favour of a variety of nondrug alternatives. We recently found, rather unexpectedly, that choice of the nondrug alternative is in fact inflexible and habitual. One possible contributing factor to habitual choice is the intermittency and uncontrollability of choice trials in previous studies.

Altered neuronal activity in the ventromedial prefrontal cortex drives nicotine intake escalation.

Nicotine addiction develops after prolonged drug use and escalation of drug intake. However, because of difficulties in demonstrating escalation of nicotine use in rats, its underlying neuroadaptations still remain poorly understood. Here we report that access to unusually high doses of nicotine (i.

Probing the decision-making mechanisms underlying choice between drug and nondrug rewards in rats.

Delineating the decision-making mechanisms underlying choice between drug and nondrug rewards remains a challenge. This study adopts an original approach to probe these mechanisms by comparing response latencies during sampling versus choice trials. While lengthening of latencies during choice is predicted in a deliberative choice model (DCM), the race-like response competition mechanism postulated by the Sequential choice model (SCM) predicts a shortening of latencies during choice compared to sampling.

Pharmacokinetics trumps pharmacodynamics during cocaine choice: a reconciliation with the dopamine hypothesis of addiction.

Cocaine is known to increase brain dopamine at supranormal levels in comparison to alternative nondrug rewards. According to the dopamine hypothesis of addiction, this abnormally large dopamine response would explain why cocaine use is initially highly rewarding and addictive. Though resting on solid neuroscientific foundations, this hypothesis has nevertheless proven difficult to reconcile with research on cocaine choice in experimental animals.

Relapse to cocaine use persists following extinction of drug-primed craving.

Craving often precedes relapse into cocaine addiction. This explains why considerable research effort is being expended to try to develop anti-craving strategies for relapse prevention. Recently, we discovered using the classic reinstatement model of cocaine craving that the reinstating or priming effect of cocaine can be extinguished with repeated priming in rats - a phenomenon dubbed extinction of cocaine priming because it is thought to involve extinction of the conditioned interoceptive cues of the drug.

Inflexible habitual decision-making during choice between cocaine and a nondrug alternative.

The concept of compulsive cocaine-seeking habits is difficult to reconcile with other evidence showing that humans and even rats remain able to shift their choice away from the drug and toward an alternative nondrug reward, when available. This paradox could dissolve if preference for the nondrug option reflected in fact inflexible habitual decision-making (i.e.

Choosing Under the Influence: A Drug-Specific Mechanism by Which the Setting Controls Drug Choices in Rats.

Ample evidence shows that the setting can control drug choices in both humans and animals. Here we reveal in rats that a major mechanism of this control involves a regulation of the drug influence on other competing options at the time of choice. Briefly, rats were offered a choice between a drug dose (cocaine or heroin) and a brief access to water sweetened with saccharin in two different settings.

Coordinated Recruitment of Cortical-Subcortical Circuits and Ascending Dopamine and Serotonin Neurons During Inhibitory Control of Cocaine Seeking in Rats.

People with cocaine addiction retain some degree of prefrontal cortex (PFC) inhibitory control of cocaine craving, a brain capacity that may underlie the efficacy of cognitive behavioral therapy for addiction. Similar findings were recently found in rats after extended access to and escalation of cocaine self-administration. Rats' inhibitory control of cocaine seeking was flexible, sufficiently strong to suppress cocaine-primed reinstatement and depended, at least in part, on neuronal activity within the prelimbic (PL) PFC.