Biology subjects

Casale, D.

Publications and source records attributed to Casale, D..

2 recordsLinked to original sources

bioRxiv2024

Triggered Temptations: A New Procedure to Compare Reward-Seeking Behaviour Induced by Discriminative and Conditioned Stimuli in Rats

RationaleEnvironmental cues guide animals towards resources vital for survival but can also drive maladaptive reward-seeking behaviours, as in gambling and eating disorders. While conditioned stimuli (CSs) are paired with reward delivery after reward-seeking actions, discriminative stimuli (DSs) signal reward availability independent of behaviour. ObjectiveWe introduce a procedure to compare CS and DS effects on reward-seeking behaviour, in the same subjects within a single session. MethodsFemale and male Sprague-Dawley rats learned to self-administer sucrose. During each session, DS+ trials signaled that lever pressing would produce sucrose paired with a CS+, and DS-trials signaled no sucrose and a CS-. Next, in the absence of sucrose, we assessed the ability of the cues to i) reinforce lever pressing and ii) increase sucrose seeking when presented response-independently. We also assessed the effects of the mGlu2/3 receptor agonist LY379268 and d-amphetamine on cue-induced sucrose seeking. ResultsBy the end of self-administration training, lever pressing peaked during DS+ trials and dropped during DS-trials. The DS+ was a conditioned reinforcer of sucrose seeking in both sexes, whereas the CS+ was more effective in males. Response-independent presentations of the DS+ invigorated sucrose seeking in both sexes, whereas the CS+ was effective only in males. LY379268 suppressed DS+-triggered sucrose seeking in females, with no effect in males. D-amphetamine enhanced sucrose seeking non-specifically across cue conditions in males, with no effect in females. ConclusionsOur new trial-based procedure can be used to identify unique and similar mechanisms underlying DS and CS influences on appetitive behaviour.

neuroscience↗

bioRxiv2024

Relapse after intermittent access to cocaine: Discriminative cues more effectively trigger drug seeking than do conditioned cues

When people with drug addiction encounter cues associated with drug use, this can trigger cravings and relapse. These cues can include conditioned stimuli (CSs) signaling drug delivery and discriminative stimuli (DSs) signaling drug availability. Compared to CS effects, DS effects are less explored in preclinical studies on cue-induced relapse. We compared CS and DS effects on reward seeking following abstinence from intermittent-access cocaine (or sucrose) self-administration. During 15-20 intermittent-access sessions, rats self-administered sucrose pellets or i.v. cocaine paired with a light-tone CS. Cocaine/sucrose was available for 5-min (signalled by a light; DS+) and unavailable for 25 min (signalled by different lighting conditions; DS-), and this cycled for 4 h/session. Following abstinence, we measured cocaine/sucrose seeking under extinction triggered by CS and DS presentation, and instrumental responding reinforced by these cues. Across intermittent-access sessions, rats increased lever pressing for cocaine or sucrose during DS+ periods and decreased responding during DS-periods. On days 2 and 21 of abstinence, only presentation of the DS+ or DS+ and CS combined elicited increased cocaine/sucrose-seeking behaviour (i.e., increased active lever presses). Additionally, presenting the DS-alongside the DS+ suppressed the increased cocaine-seeking behaviour otherwise produced by the DS+. Finally, on day 21 of abstinence, rats showed equivalent levels of lever pressing reinforced by the DS+, CS and by the DS+ and CS combined, suggesting comparable conditioned reinforcing value. After intermittent self-administration, cocaine-associated DSs and CSs acquire similar conditioned reinforcing properties, but DSs more effectively trigger increases in drug seeking.

animal behavior and cognition↗