Biology subjects

Vandaele, Y.

Publications and source records attributed to Vandaele, Y..

4 recordsLinked to original sources

bioRxiv2021

Unveiling the neural correlates of habit in the dorsal striatum

We have recently reported sustained inhibition in the dorsomedial striatum (DMS) and sustained excitation in the dorsolateral striatum (DLS) during execution of a lever press sequence in a discrete-trials task promoting habit. This sustained dorsostriatal activity was present early on, and did not clearly change in step with improved performance over ten training sessions. Early onset of sequence-related neural activity could have resulted from rapid habitual learning promoted by presentation of lever cues, predicting reward availability and delivery. To test this hypothesis, we compared DLS and DMS spiking activity in the discrete trials habit-promoting task with two task variants that promote goal-directed behavior. Comparison of the three tasks revealed that mean neuronal spiking activity was generally sustained across the lever press sequence in the task promoting habit and characterized by overall excitation in DLS and inhibition in DMS relative to baseline. In contrast, mean activity differences in DLS and DMS were much less prominent, and most changes occurred transiently around individual lever presses, in the tasks promoting goal-directed behavior. These results indicate that sequence delineation cues, such as the lever cues in these studies, promote habitual behavior and that this habitual behavior is encoded in the striatum by cue-triggered sustained DLS excitation and DMS inhibition that likely reflects cue-elicited behavioral chunking.

neuroscience↗

bioRxiv2021

Dorsomedial striatal activity tracks completion of behavioral sequences

For proper execution of goal-directed behaviors, individuals require both a general representation of the goal and an ability to monitor their own progress toward that goal. Here, we examine how dorsomedial striatum (DMS), a region pivotal for forming associations among stimuli, actions, and outcomes, encodes the execution of goal-directed action sequences that require self-monitoring of behavior. We trained rats to complete a sequence of at least 5 consecutive lever presses (without visiting the reward port) to obtain a reward and recorded the activity of individual cells in DMS while rats performed the task. We found that the pattern of DMS activity gradually changed during the execution of the sequence, permitting accurate decoding of sequence progress from neural activity at a population level. Moreover, this sequence-related activity was blunted on trials where rats did not complete a sufficient number of presses. Overall, these data suggest a link between DMS activity and the execution of behavioral sequences that require monitoring of ongoing behavior.

neuroscience↗

bioRxiv2021

Choosing between cocaine and sucrose under the influence: testing the effect of cocaine tolerance

Cocaine use not only depends on the reinforcing properties of the drug, but also on its intoxicating effects on alternative nondrug activities. In animal models investigating choice between cocaine and alternative sweet rewards, the latter influence can have a dramatic impact on choice outcomes. When cocaine intoxication at the moment of choice is prevented by imposing sufficiently long intervals between choice trials, animals typically prefer the sweet reward. However, when choosing under the drug influence is permitted, animals shift their preference in favor of cocaine. We previously hypothesized that this preference shift is mainly due to a direct suppression of responding for sweet reward by cocaine intoxication. Here we tested this hypothesis by making rats tolerant to this drug-induced behavioral suppression. Contrary to our expectation, tolerance did not prevent rats from shifting their preference to cocaine when choosing under the influence. Thus, other mechanisms must be invoked to explain the influence of cocaine intoxication on choice outcomes.

neuroscience↗

bioRxiv2020

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

Investigating the decision-making mechanisms underlying choice between drug and nondrug rewards is essential to understand how their alterations can contribute to substance use disorders. However, despite some recent effort, this investigation remains a challenge in a drug choice setting, notably when it comes to delineate the role of goal-directed versus habitual control mechanisms. The goal of this study was to try probing these different mechanisms by comparing response latencies measured during sampling (i.e., only one option is available) and choice trials. A deliberative goal-directed control mechanism predicts a lengthening of latencies during choice whereas a habitual control mechanism predicts no change in latencies. Alternatively, a race-like response competition mechanism, such as that postulated by the behavioral ecology-inspired Sequential Choice Model (SCM), predicts instead a shortening of response latencies during choice compared to sampling. Here we tested the predictions of these different mechanisms by conducting a systematic retrospective analysis of all cocaine versus saccharin choice experiments conducted in rats in our laboratory over the past 12 years. Overall, we found that rats engage a deliberative goal-directed mechanism after limited training, but shift to a SCM-like response selection mechanism after more extended training. The latter finding suggests that habitual control is engaged in a choice setting via a race-like response competition mechanism, and thus, that the SCM is not a general model of choice, as formulated initially, but a specific model of habitual choice.

animal behavior and cognition↗