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Only recently have the functional implications of the organization of the ventral striatum, amygdala, and related limbic-cortical structures, and their neuroanatomical interactions begun to be clarified. Processes of activation and reward have long been associated with the NAcc and its dopamine innervation, but the precise relationships between these(More)
Dopamine release within the nucleus accumbens (NAcc) has been associated with both the rewarding and locomotor-stimulant effects of abused drugs. The functions of the NAcc core and shell were investigated in mediating amphetamine-potentiated conditioned reinforcement and locomotion. Rats were initially trained to associate a neutral stimulus (Pavlovian CS)(More)
Experiment 1 examined whether microinjections of morphine (1 microg in 0.5 microl over 1 min x 2 pairings) into 13 different CNS sites produced a conditioned place preference (CPP). Injections into the lateral ventricles (LV), ventral tegmental area (VTA), or periaqueductal gray (PAG) produced a CPP; injections 1 mm dorsal to the PAG or VTA, or into the(More)
The relationship between impulsivity and drug abuse is poorly understood despite evidence that impulsive behaviour both predicts, and is a consequence of, drug use. Moreover, although there are clear individual differences in the propensity to addiction, this relationship has not been investigated with respect to impulsive behaviour. We tested whether early(More)
The current study investigated whether acute alcohol intoxication produces impaired decision-making on tasks assessing ventromedial prefrontal (VMF) cortex functioning and impulsive responding. Participants completed the Iowa Gambling Task (IGT), a decision-making test targeting the VMF, and the Newman Perseveration Task (NT), a measure of impulsivity.(More)
Drug addiction can be considered an impulse control disorder in that addicts exhibit increased impulsivity on both behavioural and self-report measures. We investigated whether chronic cocaine affects delay of gratification and/or behavioural disinhibition in rats using the delayed reinforcement and Go/No-go paradigms. Animals were treated with saline or(More)
RATIONALE In animal models of drug self-administration, response rates often decrease with dose suggesting that a regulative process may mask the reinforcing effects of the drug. OBJECTIVE The purpose of the present experiments was to dissociate the role of regulative and reinforcement processes in intravenous cocaine self-administration by rats using a(More)
Sustained attention requires the integrity of basal forebrain cholinergic systems. The pedunculopontine tegmental nucleus (PPTg) has direct and indirect connections (via the thalamus) with the basal forebrain, suggesting that the PPTg may also play an important role in attentional processes. We examined this hypothesis by testing the effects of PPTg lesions(More)
Opiates produce analgesia by activating mu opioid receptor-linked inhibitory G protein signaling cascades and related ion channel interactions that suppress cellular activities by hyperpolarization. After chronic opiate exposure, an excitatory effect emerges contributing to analgesic tolerance and opioid-induced hyperalgesia. Ultra-low-dose opioid(More)
Early environmental experience produces profound neural and behavioural effects. For example, animals reared in isolation show increased anxiety, neophobia, and poorer performance in learning and spatial memory tasks. We investigated whether later enrichment reverses some or all of the deficits induced by isolation rearing. Eighty-four male Long-Evans rats(More)