Behavioral Neuroscience

People often must decide how long to continue waiting for rewards that will arrive at an uncertain time in the future. We propose that these persistence decisions involve weighing the benefits of continued waiting against opportunity costs of waiting, a balance that may shift over time. This framework suggests that persistence decisions share neural mechanisms with foraging decisions, which require ongoing comparisons between a current resource and possible alternatives. Dopamine and serotonin have been proposed to play opposing roles in foraging, with dopamine promoting exploration and serotonin promoting exploitation. Here we investigated their roles in persistence. In a within-subjects, double-blind, placebo-controlled study in young adults (n = 42), we examined the effects of increasing dopamine with L-dopa and increasing serotonin with escitalopram. We predicted that L-dopa would decrease persistence and escitalopram would increase it. Participants also completed patch-foraging, time perception, risk tolerance, and temporal discounting tasks to explore potential mechanisms of drug effects on persistence. Escitalopram increased persistence, after adjusting for the effects of anxiety and condition order, such that participants waited longer for rewards after taking the serotonergic drug. L-dopa did not influence persistence. In exploratory analyses controlling for age, however, L-dopa reduced persistence and increased exploration in foraging.

Decisions are often modeled as a sequential process in which evidence accumulates until it reaches a threshold, triggering a response. Studies in freely moving animals raise questions about how ongoing behavior, not just stimulus properties, shapes this process. We trained rats of both sexes on a visual detection task with three luminance levels, each associated with the same reward outcome. Rats controlled cue duration through sustained head entries into a center port, yielding a measurable index of active sampling. Females consistently sampled longer than males. Sampling durations were shorter on error than correct trials, and reaction times were longer on error trials. We used drift diffusion models to relate these behaviors to the decision process. Luminance selectively affected the rate of evidence accumulation, with drift rate increasing monotonically across low, mid, and high luminance levels. Active sampling time was associated with the decision threshold, with longer sampling predicting higher thresholds in both sexes. The relationship between sampling time and drift rate differed by sex. Females showed a negative association between sampling duration and drift rate that was absent in males. These findings suggest that cue properties and active sampling make separable contributions to the decision process. These findings suggest that cue properties and active sampling make separable contributions to decision making, with a negative association between sampling duration and drift rate evident in females but not males.

We previously reported, using in-vivo fiber photometry, that operant responding reinforced by access to a peer (social self-administration) is associated with phasic dopamine increases in nucleus accumbens (NAc) core following lever insertion (reward-availability cue) and gradual increases preceding lever-pressing. Here, we sought to replicate these findings and determine whether dopamine signals (1) generalize to responding for high-carbohydrate palatable food, (2) show opposite patterns during negative reinforcement (shock avoidance/escape), and (3) depend on whether reinforcers are experienced alone or together. We trained rats (n=11; 6 females) to lever-press for access to a same-sex peer (15 s/trial) and palatable food (45-mg pellet/trial), followed by shock avoidance/escape (0.18-0.26 mA). After training, we expressed the dopamine sensor GRAB-DA2m and implanted optic fibers into NAc core. We measured dopamine activity during sessions with either one- or three-reinforcers. During social self-administration, dopamine activity showed phasic increases following lever insertion and gradual increases preceding lever-pressing; responses were moderately greater during sessions with all three reinforcers. Palatable food self-administration showed a similar pattern, but responses were approximately twofold greater during single-reinforcer sessions. During shock avoidance/escape, dopamine activity showed phasic decreases at warning onset, lever insertion, and shock onset; responses were also greater during single-reinforcer sessions. Results suggest that NAc core dopamine signaling distinguishes positive from negative reinforcement and is modulated by reinforcer availability. Compared with single-reinforcer sessions, dopamine responses during food self-administration and shock avoidance/escape were reduced during sessions with all three reinforcers, whereas responses during social self-administration modestly increased. Significance statementNucleus accumbens (NAc) dopamine is critical for processing the valence of positive reinforcers, whereas its role in negative reinforcement is less well understood. Here, we extended our prior work on operant social self-administration to determine whether these findings generalize to food reinforcement, show the opposite pattern during operant negative reinforcement (shock avoidance/escape), and depend on whether reinforcers are experienced alone or together. Results suggest that NAc core dopamine activity differentiates positive and negative reinforcement and is modulated by the presence of other available reinforcers. Specifically, dopamine responses during food self-administration and shock avoidance/escape were reduced when all three reinforcers were available together compared with when each reinforcer was experienced alone, whereas responses during social self-administration showed the opposite pattern.

Reinforcement learning theory formulates distinct decision-making strategies, including reactive model-free and deliberative model-based strategies. This study investigates how mice adjust their reinforcement learning strategies while learning decision-making in dynamic environments. Unlike previous studies that focused on behaviors after extensive training periods, we analyzed changes in learning strategies in the course of training of a two-step decision-making task with probabilistic state transition and fluctuating reward probabilities. Our statistical behavioral analysis showed that the stay-probability following common and rare transitions diverged with training, a signature of strategies that utilize knowledge of task structure. We fit various reinforcement learning strategies to behavioral data and found that structure-informed strategies became increasingly dominant in their behaviors during training. Whereas previous studies emphasized transition from goal-directed to habitual strategies after extensive training, which were often associated with model-based and model-free strategies, respectively, our results newly demonstrate a shift from model-free to structure-informed strategies in early training in mice. Author summaryReinforcement learning theory allows us to examine how we make decisions and what approaches we use to optimize rewards. Most previous research, however, has examined animal behavior only after extensive training. Here we analyzed how mice adjust their reinforcement learning strategies as they are trained in a two-step decision-making task. Initially, mice relied on reactive model-free strategies, but as training progressed, their behavior began to incorporate knowledge of task structure. While previous studies suggested transition from model-based to model-free strategies with extensive training, our study revealed the opposite in the early stage of training.

The noradrenergic nucleus locus coeruleus (LC) is involved in numerous cognitive functions. Its activation often enhances sensory and motor performance and its activity correlates with arousal, which altogether suggest a general role in the mobilization of resources for cognition and action. We recently showed its strong and specific implication in physical effort and indirect evidence suggest that it might also be involved in cognitive effort. To address this question directly, we used a pharmacogenetic approach in rhesus macaques to selectively and reversibly inhibit LC neurons in a cognitively challenging task. Two monkeys were injected with viral vectors expressing inhibitory DREADDs (hM4Di) specifically in noradrenergic LC neurons, allowing reversible suppression of LC activity via systemic administration of deschloroclozapine (DCZ, 0.1 mg/kg). A third monkey served as a control and only received DCZ injections. Monkeys performed a simple hole-board task in which they searched for food rewards (raisins) hidden in a 5x5 grid of wells. In the transparent condition, rewards were visible, requiring minimal cognitive effort. In the opaque condition, rewards were hidden, such that monkey had to rely upon working memory to avoid revisiting empty wells. Thus, performance in opaque condition required more cognitive effort. Behavioral analysis showed that LC inhibition had no effect on performance in the transparent condition. However, in the opaque condition, it significantly impaired performance by increasing errors (revisits), without affecting the total number of rewards obtained, response times, or overall motivation. Monkeys compensated the decrease in success rate by performing more trials, indicating reduced efficiency rather than disengagement. These findings demonstrate that the LC plays a critical causal role in mobilizing cognitive resources for a demanding task. This is in line with the idea that the noradrenergic system contributes broadly to cognitive control and effort, extending previous findings on its involvement in physical effort. Overall, the study provides strong evidence linking LC activity to cognitive effort regulation, thereby complementing non-invasive studies in humans.

Working memory has been considered a delay-dependent retention system, but variability in delay duration across species and tasks suggests that task-intrinsic factors may also contribute. Here, we investigated the effects of delay duration (75 s vs. 150 s) and task distance (0 m vs. 2 m) on working memory using a T-maze delayed alternation task with a movable home-cage apparatus in rats. At the 150-s delay, accuracy was 9% lower at 0 m than at 2 m (75% vs. 84%), with a similar numerical tendency observed at the 75-s delay (4% lower). A two-way repeated measures ANOVA revealed significant main effects of both task distance and delay duration, with no significant interaction (p = 0.217). Post hoc pairwise comparisons indicated that accuracy in the 0-m condition was significantly lower at 150 s than at 75 s (adjusted p = 0.038). At the 150-s delay, accuracy was also significantly lower in the 0-m condition than in the 2-m condition (adjusted p = 0.019). These results suggest that working memory retention is influenced not only by temporal constraints but also by task-intrinsic factors such as task distance, with the observed effects appearing independent and consistent with a two-factor framework.

Flexible decision making depends on internal representations that capture the latent structure of a task, allowing prior knowledge to be applied in novel circumstances. Spatial navigation provides a useful model for studying flexible choice behavior, because spatial location is itself a latent variable that must be inferred rather than directly perceived. Here, we trained rats on a navigation task that required them to reach the same goal via two distinct paths from different starting locations, and then return to one of the two starting locations before beginning the next trial. Some rats were trained to rely on distal visual landmarks, allowing task states to be identified from current sensory information, whereas others were trained to rely on path integration, requiring task states to be inferred from self-motion information accumulated over the preceding trajectory. Rats trained to rely on path integration acquired the task similarly to rats trained to rely on distal visual landmarks. However, reliance on path integration enhanced rats' ability to generalize their learning to novel situations, including finding the goal from an untrained starting location and adapting to a relocated goal that reversed learned choice sequences. These findings suggest that reliance on path integration promotes the acquisition and use of mental representations that capture the latent spatial structure of navigational tasks, thereby favoring flexible navigational decisions over rigid retrieval of reinforced responses. More broadly, our findings demonstrate how information available during training can shape representations learned from experience and thereby constrain the flexibility of decision making during inference.

Defensive survival behaviors are shaped by both danger attributes and internal physiological states. Well-characterized defensive responses depend not only on whether danger is potential or perceived, but also on its spatial and or temporal proximity. The relationship between danger imminence and defensive behaviors is referred to as the threat imminence continuum, which provides a conceptual framework bridging ecology and behavioral neuroscience. Although this theoretical framework is gaining momentum, another much less explored danger attribute is the extent to which the environment may be controllable. Most paradigms assessing defensive behaviors rely on conditioned stimuli as danger warning-signals in stable environments that hamper the study of environment controllability and its impact on defensive behaviors. To address this question, we repurposed the active place avoidance (APA) paradigm combined with supervised machine learning to characterize multivariate exploratory and defensive behaviors in male and female mice. One important benefit of APA is that it allows the study of active avoidance when the platform is rotating as well as deliberative avoidance when the platform is immobile. As such, APA is very well suited to test the impact of environment controllability on the expression of defensive behaviors. Using this unified preparation, we systematically compared quantitative danger attributes (punishment intensity, behavioral agency) across danger states (absence, presence and omission of punishment) and learning experience (early and late learning stages), while considering sex as a biological variable. Our results demonstrate that defensive behaviors depend on punishment intensity in a sex-dependent manner in APA. Defensive responses can be classified as proactive (risk assessment) or reactive (freezing, escape) in APA. Their response probability depends on behavioral agency, is mutually exclusive and depends on danger spatial proximity. Acute treatment with norepinephrine transporter blocker selectively increases reactive defensive behaviors while sparing proactive defensive behavior. Collectively, these results provide experimental evidence that environmental stability calibrate proactive and reactive defensive behaviors whose neural correlates may be divergent.

Older adults typically exhibit reduced episodic memory precision, while maintaining relatively preserved retrieval success. However, little is known about whether these age-related differences are influenced by internal biological factors (e.g., chronotype) or external testing conditions (e.g., experiment format, time of day). To address this question, younger and older adults completed an object-location memory task online, either in the morning or evening, and either with or without video-based supervision. Memory performance was assessed using mean absolute error and Bayesian hierarchical mixture modelling, which dissociated memory precision ({kappa}) from the probability of memory-based responding ({theta}). Immediate memory performance was high across age groups, irrespective of time of day. Greater encoding error predicted greater retrieval error, and participants tested in the video condition exhibited lower recall error and higher recognition performance than those tested without supervision. Consistent with prior studies, older adults exhibited reduced memory precision relative to younger adults, whereas retrieval success remained largely intact. However, Bayesian Hierarchical Modelling provided no evidence that time of day, experiment format, or their interactions with age influenced either memory precision or retrieval probability. Older adults reported stronger morning preferences than younger adults, and participants generally selected testing times that aligned with their chronotype. Nevertheless, alignment between chronotype and testing time did not modulate memory performance. The results indicate that age-related differences in episodic memory precision are robust across variations in testing context, including time of day, experiment format, and individual differences in chronotype. More broadly, the results support the feasibility of remote and unsupervised testing for memory precision research and suggest that chronotype and testing time are unlikely to be major sources of variability in immediate object-location memory performance.

Difficult decisions require gathering evidence over extended periods, placing demands on working memory. Yet, how working memory limitations affect decision-making remains largely unknown. We trained two macaque monkeys to perform a probabilistic reasoning task that involved extended sequential evidence sampling, requiring reliance on working memory. Monkeys made choices informed by a stream of briefly presented cues, each providing probabilistic evidence about which choice would be rewarded. In both animals, choices were significantly affected by working memory decay, primacy, recency, and priming. Despite individual differences in working memory limitations, both monkeys adopted sampling strategies that made their behavior nearly optimal. To test how dopamine affects working memory constraints on evidence accumulation, we systemically applied dopamine D1 receptor agonist and antagonist drugs midway during selected sessions. Activation of D1 receptors reduced priming. Blockade of D1 receptors reduced working memory decay and the subjective evidence weights assigned to individual cues. Our results reveal that complex decisions are constrained by working memory limitations and identify dopamine as a key modulator of this process, with potential implications for cognitive disorders and their treatment.

The rat gambling task (rGT) has been widely used to investigate the neural mechanisms underlying risky choice and motor impulsivity. Here, rats sample between four options (P1-P4) that vary in the size and probability of reward and time-out penalties. The optimal strategy is to avoid risky options that may yield higher per-trial gains, but deliver longer and more frequent time-outs. Previous reports suggest pairing wins with salient audiovisual cues increases risky decision making, but behavioural variation is high, and it is unclear whether motor impulsivity is also affected. Here we leveraged rGT data from over 750 rats to characterize behavioural performance across sex and cue condition. We compared different methods of classifying rats as optimal or risk-preferring, using either a unitary decision score variable or specific P-choice preference, and applied drift diffusion modeling (DDM) to explore whether divergent cognitive mechanisms underlie risky decision making across subgroups. We confirmed that risky choice is higher on the cued rGT, partly due to a greater proportion of risk-preferring rats, but also because net optimal decision-makers chose the risky options more often. Risk-preferring rats made more impulsive, premature responses regardless of cue condition, as did males. Optimal decision-makers made more premature responses when cues were present, such that premature response rates were higher overall on the cued rGT. DDM and response latency data suggest divergent cognitive processes underpinning risky decisions across sex. Wider decision boundaries were associated with both highly optimal and highly risky choice patterns, indicating risky choices are made deliberatively by highly risk-preferring individuals. Similar results were obtained regardless of classification method.

Animals must generalize from limited experience, yet behavioral experiments in the laboratory setting rarely assess whether or how rapidly they generalize. This contrasts with machine learning systems, where generalization is considered a fundamental test of learning, and emphasizes performance evaluation with new in-distribution or out-of-distribution examples. Here, we used an olfactory categorization task to investigate rules of generalization versus memorization in mice. We trained mice to discriminate between two target odorants mixed with a variable number (0-13) of background odors. There are 32766 possible mixture stimuli to be classified, yet mice learn to generalize from as few as 8 unique mixtures. This generalization is not due to limited memory capacity: mice successfully learned to group the same set of mixtures when category labels were randomly shuffled. Analysis of individual variability revealed features in learning dynamics during training that predict performance in the generalization phase. A linear supervised learning algorithm could describe the generalization from few exemplars well, whereas nonlinear classifiers were necessary to explain memorization. Our experiments suggest that mice have an inductive bias towards generalization, consistent with a preference for simple rules, and will memorize only when forced to do so.

Recent research has suggested that the availability of non-instrumental information about the outcome of a risky choice increases risk appetite. In this study, we aimed to perform a conceptual replication of these findings and to examine the cognitive mechanisms underlying this effect. Across two experiments (N = 150, 102), we presented participants with mathematically fair gambles and allowed them to choose the size of their bet. Between trials, we varied the presence of non-instrumental information that would reveal the outcome ahead of time. In both experiments, we did not find consistent evidence for an effect of the availability of non-instrumental information on bet size. These findings suggest that the previously reported effects of non-instrumental information on risk appetite may have been an idiosyncratic feature of experimental design, rather than a more general phenomenon that characterises human decision making under risk.

Operant paradigms are powerful tools to quantify motivation and reward. Traditionally, operant conditioning research has been limited to food and drug reinforcers. Recent advances in commercially available operant equipment, however, allow for the quantification of social motivation. These operant assays are an improvement over commonly used social preference tasks, as they enable direct measurement of the effort and motivation driving social behavior. Based on a design by Venniro et al. (2020), the MedPC social operant boxes modify the traditional operant box setup for social interactions. The experimental rat can lever-press to raise a door for an interaction with a target rat behind a porous barrier. These social operant boxes have been widely adapted to test social behavior in adult and adolescent rodents and investigate how a range of conditions (e.g. stress, drug taking, etc.) affect social motivation. However, there is a gap in assessing maternal motivation for pups during the postpartum period, despite ample evidence that postpartum social behavior is highly relevant for offspring health outcomes. Here, we detail 3D-printed modifications to the standard Med PC social operant boxes to adapt the social target chamber to safely house neonatal pups. We have also developed testing protocols to assess motivation during the limited postpartum period. These data demonstrate that, with simple modifications to social operant chambers and testing protocols, the field can implement advanced behavioral approaches to directly assess maternal motivation.

Making choices about whether and when to engage cognitive effort is a common feature of human everyday experience with important consequences for academic, career, and health outcomes. Yet, despite its importance, little is understood about the neurochemical mechanisms that underlie individual differences in the willingness to engage in cognitively effortful activities. To examine this question, we employed a multi-modal neuroimaging approach in which participants performed the Cognitive Effort Discounting paradigm (Cog-ED) while simultaneous PET-fMRI was acquired. We assessed both individual differences in dopamine-D2 receptor availability and brain activity during decision-making. In addition, the same participants performed a parametric working memory task (N-Back) and reported the cognitive effort associated with their daily life activities through a seven-day Ecological Momentary Assessment (EMA) protocol. The findings suggest a central role for caudate dopamine-D2 receptors in modulating cognitive effort-related motivation. People with higher caudate dopamine-D2 receptor availability had better working memory function, heightened sensitivity to effort costs, and greater modulation of brain activity during effort valuation. These laboratory findings also translated directly to daily life: higher levels of caudate dopamine-D2 receptors were associated with greater engagement in cognitively effortful activities. Together, the results suggest that how individuals determine the motivational value of cognitively effortful activities strongly depends on the dopamine system.

Background: ADHD is characterized by inattention and impulsivity. Stimulants such as amphetamine are the first line treatments for ADHD. Amphetamine (AMPH) works by increasing extracellular levels of dopamine and noradrenaline. Such stimulants are used to test predictive validity of animal tasks, where it has been reported that amphetamine improves rat 5-CSRTT accuracy when the session length is increased to 250 trials. This improvement in accuracy was observed later in the session as control performance declined. Proving that amphetamine can improve 5C-CPT task performance adds to the predictive validity of the task. No previous works has demonstrated the pro-attentional effects of amphetamine on sustained attention in rat 5C-CPT. We have previously shown that pharmacological manipulations of dopaminergic system improve waiting impulsivity in a rate dependent manner and the importance of analysing the data using Oldham method. The present study extends this work to investigate the effect of amphetamine on attentional processes. Objective: to investigate effects of amphetamine on attentional processes as measured by 5C-CPT task using correlational analysis and group performance. Methods: Trained female Lister hooded rats were tested with AMPH (0.1, 0.2 and 0.4 mg/kg) under reduced stimulus duration schedule (0.25,0.5,1,1.5 and 2s SD) over normal length session (120 trials). Correlational analysis (Oldham method) was used to understand the relationship between baseline performance measures and the change following administration of AMPH. Results: The highest dose of AMPH impaired attentional performance in the 5C-CPT under reduced SD challenge (0.5s,1s,1.5s and 2s). This impairment was due to increase in FAR. Previous studies in 5-CSRTT suggest that reducing the SD increases attentional demand in the form of reducing accuracy without affecting waiting impulsivity. However, the 5-CSRTT does not include non-target trials, therefore, it cannot be used to measure sustained attention (SI) and responsivity index. The 5C-CPT requires greater attentional resources than the 5-CSRTT.This study is the first to report that reducing the SD changes responsivity index (bias) rather than measures of sustained attention (sensitivity index) in the 5C-CPT. Control sensitivity index did not change until the SD was reduced to less than 0.5s and this change was due to a change in baseline responsivity index (bias). Performance under each reduced SD revealed that the highest dose of AMPH (0.4 mg/kg) showed a tendency toward reducing sensitivity index at 0.5, 1.0 and 1.5s SDs. Under 1.0s SD, the highest dose of AMPH changed sustained attention (SI, HR and FAR) and omission in a rate-dependent manner without changing responsivity index. Performance across the session revealed that the impairment in sustained attention was observed at the beginning of the session. In the third trial block, Oldham method revealed an inverse relationship between baseline accuracy and the change following administration of 0.2 mg/kg AMPH, indicative of a rate-dependent effect. Conclusions: This study successfully demonstrates rate-dependent effects of AMPH on measures of attentional performance in the 5C-CPT. This experiment also demonstrates that responsivity index is sensitive to reduced SD challenge. To our knowledge this is the first study to report the presence of a direct relationship between baseline sustained attention and magnitude of improvement following administration of 0.4 mg/kg AMPH and an inverse relationship between baseline accuracy and the change following administration of 0.2 mg/kg AMPH in 5C-CPT task. Future studies should test lower doses of amphetamine (0.05 and 0.1 mg/kg) over extended session length (250 trials) to reveal the pro-attentional effects of this drug on 5C-CPT performance measures.

Learning to accurately estimate temporal intervals and spatial magnitudes is important to everyday behavior, yet few studies have directly compared how learning unfolds across these domains. Theoretical models of temporal interval estimation provide conflicting accounts of how this learning process might occur and how it might differ from other entities like spatial line estimation. In the present study, participants completed temporal interval and line-length production tasks under feedback or no-feedback conditions during a training phase. They were then tested without feedback and subsequently presented with untrained temporal intervals and line lengths to examine whether learning generalized to novel magnitudes. We found that both temporal and spatial production exhibited similar learning trajectories, characterized by rapid initial improvements, followed by asymptotic performance. Despite similar learning trajectories, however, spatial production reached higher levels of accuracy and precision faster and in a more sustained manner than temporal production. Feedback facilitated learning in both domains, with improvements in precision emerging early during training and improvements in accuracy becoming evident during the subsequent test phase. These benefits persisted into the transfer phase, particularly for spatial production, indicating that feedback-supported learning generalized to untrained magnitudes. Transfer performance also reflected systematic biases in magnitude estimation, consistent with a central tendency effect, with shorter magnitudes tending to be overproduced and longer magnitudes underestimated. Together, these findings demonstrate that temporal and spatial magnitude learning share some common and some dissociable learning dynamics, providing new insight into the shared and distinct mechanisms underlying magnitude learning and highlighting the important role of feedback in promoting learning and transfer.

Animals differ in how they acquire and retain information, and modify their behavior while interacting with their environment. These differences have been linked to personality type, yet how personality type and sex influence reward-associated memory is not well understood. We investigated the effects of personality type, sex, days of conditioning, and food reward on learning and memory retention in zebrafish using the conditioned place preference paradigm. We conditioned zebrafish to associate a visual background with a food reward across eleven sessions and assessed memory recall seven days later by measuring duration, frequency of entry, and latency to first entry in the conditioned zone. We observed that bold fish had early conditioned zone engagement, whereas shy zebrafish gradually increased their behavior into the conditioned zone with repeated conditioning. With food reward, preference for the conditioned zone increased after 7 and 11 days post-conditioning relative to baseline. Seven days after the last conditioning with food reward, the preference for conditioned zone remained unchanged in shy fish. This suggests that shy fish retain the ability to recall the learned association for at least 7 days after conditioning. Overall, personality, food reward, and sex influence behavioral changes in food reward-associated cognition, with shy-treated males showing gradual increases in behavior into the conditioned zone. These findings suggest that personality and sex differences may depend on the nature and valence of the associative task to recall. Thus, this study emphasizes the importance of assessing memory retention alongside learning acquisition to understand the relationship between personality types and cognition.

Understanding the neurobiological systems that regulate alcohol cue-induced craving is of utmost importance for the development of novel intervention strategies for alcohol use disorders (AUDs). However, although a human experimenter is required to conduct alcohol self-administration studies in the lab, the cues associated with the experimenter are seldom if ever factored into the experimental design. Thus, although we have learned much to date about alcohol cue-induced behavior and neurobiology, and in particular about discrete cues presented many times throughout a single daily alcohol self-administration session, we know relatively little about how responses to alcohol availability cues might predict subsequent alcohol consumption. For the current experiment, mice were exposed daily to auditory cues that preceded 2 hours of alcohol or water access using drinking-in-the-dark (DID) methods. An additional control group experienced cues but were not otherwise manipulated. Importantly, cues were initiated remotely from outside the animal facility, avoiding the experimenter being the first cue predicting ethanol availability. Head direction, location in the home cage, and movement velocity were the primary variables on interest. Surprisingly, during the cue period, there were no significant differences between groups in any of these measures, despite meaningful alterations over days. However, we observed many significant correlations between behaviors and drinking variables. First, we observed significant positive associations between ambulatory velocity during cues and subsequent total alcohol (R2=0.14; p<0.0001) and total water (R2=0.12; p=0.0002) consumption, but only in females. We also observed a significant positive relationship (R2=0.25; p<0.0001) between the amount of time oriented toward the sipper port during the auditory cues and the average rate of subsequent alcohol consumption (i.e. front-loading), but only in females. In males, head direction was found to be positively associated with subsequent total water consumption (R2=-0.21; p<0.0001), but not alcohol (R2=-0.01; p=0.2267). We also observed a significant negative relationship (R2=-0.15; p<0.0001) between proximity to the sipper during the cue period and subsequent total 2-hour alcohol intake in males. Although these associations were modest in strength, they suggest potential sex-specific behavioral predictors of alcohol consumption that are regulated by different neural dynamics.

Rationale: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have attracted interest for their effects on motivational processes beyond satiation and weight loss, including motivation for drug rewards. Reward-predictive cues can acquire motivational value and promote food- and drug-seeking, raising the possibility that GLP-1RAs affect intake by altering cue-motivated behavior. Preclinical studies report reduced food intake and responding for drug rewards following GLP-1RA treatment. However, many preclinical studies have used acute treatment; whereas, clinically, GLP1-RAs are administered as chronic treatments with dose escalation to mitigate adverse effects. Objectives: Using a modified Pavlovian conditioned approach (PavCA) paradigm, we directly compared the effects of acute and chronic semaglutide treatment on conditioned approach behavior elicited by cues predicting different magnitudes of palatable food reward in male and female rats. Results: Although both treatment regimens reduced body weight relative to vehicle treatment, chronic semaglutide increased, whereas acute semaglutide decreased, sign-tracking toward reward-associated cues. Rats exhibited greater sign-tracking toward cues predicting large versus small rewards, but semaglutide did not differentially alter this reward-magnitude effect. Acutely treated rats consumed fewer reward pellets and exhibited less food-cup activity during non-cue periods. These findings suggest that nonspecific behavioral suppression or malaise may have contributed to reduced responding after acute treatment. Conclusions: The effects of semaglutide on cue-motivated behavior depend on the treatment regimen. Acute-treatment studies should be interpreted cautiously because adverse or nonspecific effects may contribute to apparent reductions in motivation.