Behavioral Neuroscience publications

Instrumental learning typically requires hundreds to thousands of trials in which subjects learn to link motor responses to sensory cues. In standard rodent protocols, response accuracy is reported only at trial end, preventing subjects from correcting erroneously initiated responses. We hypothesized that within-trial, closed-loop sensory feedback would accelerate instrumental learning by providing real-time information about response correctness. Head-fixed mice performed a two-alternative forced-choice task by rotating a choice wheel in response to sensory cues. Mice received either no feedback (n = 18), auditory feedback (n = 16), or audiovisual feedback (n = 4) coupled to wheel movements. Feedback-receiving mice required significantly fewer trials to reach 70 % accuracy criterion (median: 3186, 4918 and 7329 trials for multimodal, unimodal and no feedback, respectively; p = 0.0245) and showed higher accuracy when modifying choices (expert stage: 17 %, 11 % and 9 % accuracy in trials with modified choices for multimodal, unimodal and no feedback, respectively; p=1.04×10⁻⁶). Only feedback mice displayed movement refinements across training (p = 8.02×10⁻⁶, p = 4.07×10⁻¹⁸ and p = 0.2602 for multimodal, unimodal and no feedback, respectively). In summary, closed-loop sensory feedback accelerated instrumental acquisition, demonstrating its value as routine training protocol. HIGHLIGHTS Mice provided with feedback require fewer trials to reach expert stage in an instrumental learning task Mice provided with feedback perform with higher accuracy in trials involving ‘changes of mind’ Movement trajectories of mice provided with feedback undergo refinement as training advances Sensory feedback can be used as a training aid to accelerate instrumental learning

Hippocampus, a key hub of neural circuits for spatial learning and memory, has attracted tremendous studies. Neuronal information processing in the hippocampus can be regulated by many types of neuropeptides. Cholecystokinin ( Cck ), the most abundant neuropeptide in the central nervous system that is involved in modulating neuronal functions, such as cognition, memory, and neuroplasticity, is widely expressed in the hippocampus. However, whether local excitatory Cck neurons modulate hippocampal function is still unclear. In this study, we showed that CA1 pyramidal neurons receive projections from excitatory Cck neurons in area CA3 (CA3 Cck neurons) in adult mice. Subsequently, activation of the CA1-projecting CA3 Cck neurons triggers the release of Cck . Then, we found that the activity of CA3 Cck -CA1 neurons supports the hippocampal-dependent tasks. Furthermore, inhibition of CA3 Cck -CA1 projections or knockdown of CA3 Cck gene expression markedly impaired the behavioral tasks and neuroplasticity. Taken together, these results may add to a better understanding of how neuromodulators regulate the neural functions in the central nervous system.

The parabrachial nucleus (PBN) is an important hub located in the pons that relays sensory signals from peripheral regions. It is genetically diverse and contains many populations that modulate feeding and responses to threatening situations. A small Ntsr1 -expressing population of neurons was identified that projects selectively to the ventromedial hypothalamus (VMH). The Ntsr1 neurons are scattered throughout the lateral PBN with a cluster of cells along the border to the nucleus of the lateral lemniscus that overlap with Cck and Foxp2 expression. Chemogenetic activation of PBN Ntsr1 neurons results in Fos induction in Nr5a1 (SF1) and Bdnf neurons in the VMH. Activation of PBN Ntsr1 neurons or their terminals in the VMH reduces food intake after fasting and increases anxiety-like behaviors. In anxiogenic feeding assays, activation of PBN Ntsr1 neurons increases latency to feed as well as reducing food intake. Photometry showed that PBN Ntsr1 -neuronal activity increases during anxiogenic situations but is suppressed during food consumption, suggesting a role in threat-induced suppression of feeding. Silencing PBN Ntsr1 neurons with tetanus toxin light-chain increased food intake and reduced anxiety. These findings reveal a genetically defined PBN to VMH circuit that responds to threats and suppresses feeding behavior.

Phasic dopamine signalling updates the value of stimuli and actions. Most empirical support for this critical process involves manipulation of extrinsic stimuli (e.g., reward magnitude, reward omission). Yet interoceptive signals clearly influence motivated behaviour. Sodium depletion generates a sodium appetite where the value of sodium increases. How the value of sodium is updated during ingestion and as animals satiate their need remains unknown. Here, we administered sodium chloride solutions via intraoral delivery and measured appetitive behaviour and dopamine release in sodium replete and deplete rats. Two different concentrations of sodium chloride were used to modulate the rate of repletion for sodium deplete rats. Appetitive behaviour was evoked by infusions only when rats were deplete, and this behavioural motif faded away during the session only when high concentration infusions were delivered. Phasic dopamine release in the nucleus accumbens had a similar pattern. We identified transition points for both behaviour and dopamine in the subgroup of rats that reached satiation and found that transitions were sharp, with dopamine decreasing just before behaviour. Moreover, transitions occurred only after enough sodium was infused to replace that typically lost upon depletion. These findings demonstrate that mesolimbic dopamine dynamically updates the value of taste stimuli based on interoceptive signals that relay satiation.

Dopamine contributes to reward-related decision making, but its contributions to decision contexts that include explicit punishment are less well understood. To elucidate the role of ventral tegmental area (VTA) dopamine neurons in decision making under risk of punishment, we used fiber photometry to record activity in these neurons during a decision-making task in which rats choose between a small, “safe” reward and a large reward associated with varying probabilities of explicit punishment. Dopamine neuron activity exhibited phasic increases during risky “Wins” (reward without punishment) and phasic decreases during risky “Losses” (reward plus punishment), each of which scaled with punishment probability and intensity. Further analyses revealed that this outcome-evoked activity predicted choices on subsequent trials. To determine whether VTA dopamine neuron activity plays a causal role in these risk-based decisions, we used optogenetics to selectively inhibit these neurons during risky Wins and Losses. Inhibition of VTA dopamine neurons during Wins selectively reduced the frequency of risky choices after a Win, whereas inhibition during Losses selectively reduced the frequency of risky choices after a Loss. These data reveal that VTA dopamine neuron activity during outcome receipt is causally related to subsequent decision-making behavior. In addition, the fact that the effects of inhibition on choice behavior were specific to the outcome with which the inhibition was paired suggests that VTA dopamine neuron activity contributes to updating after Wins and Losses independently. Significance Statement Dopamine is implicated in movement, motivation, and learning, and has been strongly linked with substance use and risk-seeking behavior. Despite these associations, it is unclear how the activity of dopamine neurons influences decision making under risk of punishment. To elucidate this, we recorded from ventral tegmental area (VTA) dopamine neurons and found that their activity at the population level integrates reward alongside the probability and intensity of punishment experienced during risky outcomes. Further, inhibition of VTA dopamine neuron activity during risky outcomes decreased risk-seeking behavior in an outcome-specific manner. Our findings align with models suggesting that VTA dopamine neurons signal prediction errors, and provide insight into the role of these neurons in adaptive decision making.

The frontopolar cortex (FPC) is thought to coordinate the more posterior lateral prefrontal cortex (LPFC) during complex, nonroutine behaviors through high-level functions such as management of multiple goals, exploration, and self-generated decision-making. However, direct neurophysiological comparisons with other prefrontal regions are lacking, leaving the FPC’s putative dominance untested. Contrary to this view, our comparison of neuronal activity across the full anteroposterior LPFC in macaques during six distinct tasks probing these functions revealed a posterior-to-mid LPFC dominance, with resource-allocation signals, novelty- and reward-related learning signals, and modality-invariant decision-monitoring signals all showing a common posterior bias. In contrast, regardless of the task demands, FPC exhibited inflexible encoding of just-executed actions and consistent task-related deactivation resembling default-mode network activity. We identified a turning point in this graded posterior-to-anterior transition from task-positive to task-negative regions around the border between the anterior and middle thirds of the LPFC. These findings challenge the prevailing notion that the LPFC is anterior dominant across primate species and provide evolutionary constraints on theories of human prefrontal organization.

Auditory decision-making requires transforming sensory inputs into meaningful choices by integrating external stimuli with internal cognitive processes. Classical hierarchical models propose sequential processing, where primary sensory areas relay sensory information to higher-order regions that compute decision-related processes. However, whether this sequential hierarchy fully captures cortical dynamics remains unclear. Here, we analyzed simultaneous neuronal recordings from primary auditory cortex (A1) and dorsolateral prefrontal cortex (PFC) in two male macaque monkeys performing a spatial auditory decision-making task. Our analyses revealed a clear temporal hierarchy: sensory information was unidirectionally transferred from A1 to PFC, while decision-related information exhibited a bidirectional transfer, first from PFC to A1, and crucially back from A1 to PFC. These findings extend classical hierarchical assumptions, demonstrating a recurrent loop between A1 and PFC during decision-making, and offer a dynamic perspective on the integration of sensory and cognitive processes in the cerebral cortex.

Purpose: In anesthesia research and clinical practice, the level of consciousness is often assessed by stimulating subjects and observing their responses. It is possible that such stimulation alters the very state of consciousness being assessed. Whether this phenomenon is accompanied by specific cortical activities remains unknown. Here, we tested the effects of behavioral assessments on neuronal activity in the rat primary auditory cortex (A1) and perirhinal cortex (PrC). Methods: Neuronal spiking activity was recorded from microwire arrays targeting A1 and/or PrC in rats (n = 9), whilst presenting 40 Hz click-trains and gradually increasing infusion rates of propofol, remifentanil, ketamine or dexmedetomidine. We assessed righting reflex, pain withdrawal, whisking reflex, and corneal reflex every 12 minutes (every 360 auditory trials). We searched for significant changes in baseline firing rate and stimulus-evoked activities (where present) due to the behavioral assessments, by comparing 4 min intervals before and after the behavioral tests. Results: Out of 1004 units in 20 sessions, we found significantly elevated activity (p < 0.01) following behavioral tests in 32% and 20% of A1 auditory-responsive units and 8.6% and 5.3% of auditory-unresponsive units under propofol and dexmedetomidine, respectively, but not under remifentanil or ketamine. A higher proportion of units modulated their firing following behavioral tests in A1 compared to PrC, with median gains ranging from +0.23 to +1.06, depending on the specific response feature. Conclusion: Behavioral testing increases ongoing firing rate and responses to sounds in some cortical neurons. This increase is more prevalent in A1 than in PrC, mirroring clinical observations that patients exhibit basic responses under sedation, while complex processing, such as memory encoding, is impaired. The degree of neuronal modulation due to behavioral testing varies between anesthetic agents, mirroring their clinical phenotypes.

Auditory and vestibular symptoms in vestibular migraine, cochlear migraine, and Ménière's disease overlap, yet mechanisms linking migraine biology to inner ear dysfunction remain unclear. Calcitonin gene–related peptide (CGRP) is a key mediator of trigeminovascular activation and a major therapeutic target in migraine, but its contribution to cochlear dysfunction is not well defined. Using a repeated nitroglycerin (NTG) paradigm in male Wistar rats, we investigated whether a systemic migraine‐like state affects cochlear function and whether these effects are dependent on CGRP. Rats received saline, NTG, or NTG followed by the CGRP receptor antagonist olcegepant (OLC). NTG increased plasma TNF‐ α and elevated trigeminal c‐Fos; olcegepant partially normalized these markers, whereas behavioral changes in the open‐field test were interpreted cautiously because baseline immobility differed across groups before treatment. NTG produced frequency‐dependent changes in distortion‐product otoacoustic emissions and auditory brain stem response thresholds. Electrocochleography showed limited changes, and scala media proportions did not differ significantly among groups, indicating no evidence of overt endolymphatic hydrops at the studied time point. Inner hair‐cell synaptic markers showed no significant group differences for CtBP2, whereas GluR2 puncta differed between NTG and NTG + OLC ( p = 0.012). Olcegepant attenuated NTG‐associated cochlear functional changes and was associated with differences in postsynaptic GluR2 puncta, alongside region‐specific changes in cochlear CGRP immunoreactivity. These findings support a mechanistic link between migraine‐like trigeminovascular activation and early cochlear dysfunction and suggest that CGRP receptor blockade may benefit migraine patients with cochlear or vestibular symptoms. Future studies should assess females, estrous cycle tracking, hormones, and sex‐specific auditory responses.

Background/Objectives: Dopamine is well known for its role in reward learning, where phasic activity encodes prediction errors and supports the formation of cue–outcome associations. More recently, dopamine has been implicated in encoding salience, novelty, and aversive events, suggesting a broader function in shaping learning and memory across motivational contexts. However, how accumbal dopamine contributes to the recovery of extinguished fear, a process central to relapse in anxiety and trauma-related disorders, remains unclear. Methods: Here, we examined NAc core dopamine dynamics during shock-induced reinstatement of an extinguished fear memory. Using dLight fiber photometry, we found that a sustained decrease in baseline dopamine marked extinction recall. In contrast, an unexpected reminder footshock prevented this reduction, maintaining dopamine levels near baseline as freezing behavior re-emerged. Results: The reminder shock also evoked a transient dopamine peak, and optogenetic manipulations demonstrated that dopamine signaling during this period bidirectionally modulated reinstatement, with enhancement of dopamine release increasing reinstatement and inhibition of dopamine terminals markedly attenuating it. Together, these results demonstrate that unexpected aversive events reset NAc core dopamine levels and gate the return of extinguished fear. Conclusions: By revealing that accumbal dopamine contributes to fear recovery, this work broadens current models of dopamine function and identifies a neural mechanism through which surprising events may promote relapse of aversive memories in anxiety- and stress-related disorders.

Current disease-sensing devices primarily focus on distinguishing between healthy and diseased states, effective for diagnosis but limited in guiding optimal intervention timing for prevention. We developed a tripartite framework identifying pre-disease state in depression, a reversible phase preceding irreversible onset. Using complex systems theory, we analyzed early-warning signals emerging as biological systems approach critical transitions. Continuous monitoring of nine multimodal biomarkers—spanning electrophysiological, behavioral, and biological—enabled classification into normal, pre-disease, and disease states by quantitatively defining critical points. An artificial intelligence agent classified disease states with 95.2% accuracy using multimodal data, enabled by ultrasoft neural probes for stable, low-damage recordings. Therapeutic validation with a skin-attachable wireless vagus nerve stimulator integrating soft three-dimensional electrodes demonstrated superior efficacy during pre-disease states. Subjects treated during pre-disease showed faster recovery and greater therapeutic responses, while those treated after disease onset failed to achieve full recovery. This framework provides evidence-based rationale for early intervention.

Addicted individuals prefer drug rewards over natural rewards. Dysregulated dopamine (DA) signaling in the nucleus accumbens is thought to trigger this phenomenon, but there is little supporting evidence. Using a genetically encoded sensor, we monitored DA dynamics in mice in an operant associative task with natural (fat solution) or artificial (cocaine or optogenetic DA self-stimulation) rewards. During learning, DA transients emerged at predictive cues for both reward types, vanished at natural reward delivery, but persisted at artificial reward delivery. In choice sessions, animals’ preferences varied from exclusive natural reward to exclusive artificial reward. Individual preferences were predicted by cue-evoked DA response magnitudes. Revaluation of reward contingencies shifted reward-type preference and DA signaling accordingly, but not in mice showing compulsive drug seeking, indicating impaired value updating in these mice. These results support a model in which DA drives adaptive reward seeking, with persistent cue-associated DA signaling underpinning addiction vulnerability.

Exposure to stress can cause long-lasting enhancement of fear and other defensive responses that extend beyond the cues or contexts associated with the original traumatic event. These nonassociative consequences of stress, referred to as fear sensitization, are thought to underlie some symptoms of trauma-related disorders. Fear sensitization has been predominantly studied using the stress-enhanced fear learning (SEFL) paradigm, which models the stress-induced amplification of fear learning. Less is known about the mechanisms through which unlearned fear responses are sensitized by stress. Here, we investigated the neural mechanisms for sensitization of unlearned fear responses using a paradigm we termed stress-enhanced fear responding (SEFR). In this model, mice exposed to a single session of footshock stress exhibit enhanced freezing to a novel tone stimulus. To investigate brain regions that might mediate SEFR, we first used c-Fos mapping to identify neural activity changes associated with stress-induced enhancement of unlearned fear. Our c-Fos screen identified the posterior paraventricular thalamus (pPVT) as a region that was persistently hyperactive after footshock stress and whose activity correlated with behavioral expression of SEFR. Using fiber photometry, we observed that SEFR, but not SEFL, was associated with increased activity in the pPVT. Next, we found that chemogenetic inhibition of the pPVT blocked both the induction of SEFR during stress and its later expression, while artificial stimulation of pPVT in stress-naive mice was sufficient to recapitulate SEFR. Interestingly, pPVT inhibition or stimulation did not affect acquisition or expression of SEFL. In conclusion, our results indicate that sensitization of fear learning (SEFL) and sensitization of unlearned fear (SEFR) have distinct neural mechanisms. Our results identify pPVT hyperactivity as a mechanism for stress-induced sensitization of unlearned fear and highlight pPVT as a potential target for treating arousal and reactivity symptoms of trauma- and stressor-related disorders.

The basolateral amygdala (BLA) is important for assigning emotional weight to environmental stimuli to guide learning, discrimination, and adaptive vigilance. The contribution of neuromodulator inputs such as dopamine to this process is unclear. Here, we recorded in vivo BLA dopamine signals across emotional learning paradigms. We show that BLA dopamine scales with a stimulus's emotional intensity, but not value or associative strength, and reward-predictive cues evoke BLA dopamine signals that diminish, rather than grow, with training. In a complex learning context, where rats discriminated between multiple valenced associations, the magnitude of cue-evoked BLA dopamine re-scaled to report the level of relative emotional saliency. Threat and safety cues prompted larger, sustained dopamine signals compared to reward and neutral cues. Together, our data reveal a pattern of dopamine encoding with a unique contribution to learning, for dynamic disambiguation of affective states.

Adult neurogenesis sustains olfactory function, facilitates the acquisition of new memories, and provides resilience against depression in mice. Neural stem cells (NSCs) elicit selective responses to different physiological and pathological stimuli, thereby modulating neuron production. Here, we show that fear conditioning stimulates neurogenesis in the adult mouse brain septum by activating NSCs in the dorsal septum (dsNSCs) situated near a plexus of serotonergic axons originating from raphe nucleus neurons—key regulators of mood, anxiety, and stress responses. Elevation of serotonin (5HT) levels with the antidepressant and anxiolytic drug fluoxetine similarly promoted dsNSC proliferation and neurogenesis. The adult-born GABAergic interneurons integrate into septal nuclei. These findings suggest a potential adaptive response in mice to stress-inducing aversive experiences and elevated 5HT in the adult septum.

Adaptive behavior requires that behaviorally relevant signals gain access to neural circuits guiding action. The thalamus has long been proposed to regulate information flow to cortical and subcortical systems, yet whether it also tracks internally generated goal signals remains unclear. Here, we show that neurons in the paraventricular thalamus (PVT) projecting to the nucleus accumbens (NAc) encode the motivational value of safety during active avoidance. As mice learn to avoid threat, PVT→NAc neurons develop a signal that emerges selectively at successful avoidance, is experience-dependent, and diminishes following outcome devaluation. Selective silencing of the PVT→NAc pathway at safety onset reduces the motivational value assigned to safety without impairing action–outcome learning. Mechanistically, PVT input engages cholinergic interneurons (CIN) in the NAc to regulate dopamine release via synaptic potentiation mediated by GluA2-lacking AMPA receptors at PVT–CIN synapses. Disrupting this plasticity reduces the motivational impact of safety. These findings identify a thalamostriatal mechanism through which learned goals gain stable access to motivational circuitry.

Social recognition, the ability to distinguish between individuals, is essential for cognitively demanding social behaviors. The anterior olfactory nucleus (AON), a primary olfactory cortical region, is implicated in this process, but the underlying neurocircuitry remains poorly understood. Here, we generated a novel mouse line to enable genetic access to AON pyramidal neurons and mapped their whole-brain synaptic inputs and outputs. The medial prefrontal cortex (mPFC), a crucial hub for social cognition, is the primary neocortical target of AON neurons, which form monosynaptic excitatory connections with a substantial fraction of mPFC neurons. The AONmPFC pathway is activated during social investigation, and chemogenetic inhibition of this pathway impairs social recognition. Moreover, an analogous AON-prefrontal pathway is present in humans, as supported by resting-state functional magnetic resonance imaging (fMRI) functional connectivity analyses. Taken together, these findings reveal a conserved olfactory-prefrontal circuit spanning mice to humans, potentially linking olfactory dysfunction to neuropsychiatric disorders.

A central goal in neuroscience is to develop cross-species frameworks that reveal conserved principles of movement control. Recent work has suggested a potential species difference in the role of primary motor cortex (M1) during skilled forelimb tasks: in rodents, extensive practice appears to shift control to subcortical circuits, leading to "disengagement" of M1 from task execution. Importantly, there is no evidence of such disengagement in macaques. We hypothesized that these differences instead reflect task demands, particularly the need for fine (i.e., grasping) versus gross motor control. Strikingly, M1 lesions in macaques produced recovery patterns similar to rodents: gross motor control, including an exclusively gross motor task, recovered rapidly, whereas fine motor control exhibited persistent deficits. Detailed kinematic analyses in both macaques and mice performing a single-pellet reach-to-grasp task (RGT) revealed analogous disruptions in the temporal structure of sub-movements. These findings underscore the importance of task design and the translational value of rodent models for understanding motor control and recovery.

Alcohol Use Disorder (AUD) is a significant health concern characterized by cognitive dysfunction and an inability to control alcohol intake, leading to severe social and health consequences. It is crucial to uncover neuroadaptations and cellular mechanisms responsible for poor decisions surrounding alcohol drinking. Although the mediodorsal thalamus (MD) is an essential brain region for cognitive function and reward-guided choices, the effects of alcohol dependence on MD neuroadaptations and how dependence alters MD activity during choice behaviors for alcohol over natural rewards (i.e., sucrose) are not well understood. Genetic and physiological adaptations in the MD were assessed in mice treated with the chronic intermittent ethanol (CIE) exposure model of dependence, which increased alcohol intake and preference during choice sessions for water or sucrose in males and females. Results indicated that CIE exposure induced time-dependent changes in c-Fos and transcript expression and increased excitability of MD neurons during withdrawal. Enrichment analysis of alcohol-sensitive genes revealed dysregulation of genes that control glial function and axonal myelination. Fiber photometry recordings demonstrated that MD activity was elevated at the start of and after licking bouts for alcohol, water, or sucrose, and the signal for alcohol was significantly higher than the signal for other solutions in control and alcohol dependent mice. These findings demonstrate that CIE exposure causes alcohol-biased choice behaviors and genetic and physiological neuroadaptations in the MD, with MD neurons showing a unique response to alcohol over other solutions.

Contextual encoding in the dorsal hippocampus (DHPC) may recruit hypothalamic feeding modules to calibrate eating across environments, but the mechanistic instantiation of cells and circuits that undergird these processes is limited. Single-cell transcriptomics and transsynaptic tracing of the dorsolateral septum (DLS) identified an evolutionarily conserved prodynorphin (Pdyn)-expressing subpopulation of somatostatin (Sst)-expressing inhibitory neurons that receives dense dorsal, but not ventral, hippocampal inputs. Circuit optogenetics, electrophysiology, and in vivo calcium imaging demonstrated that DLS(Pdyn) neurons inhibit GABAergic neurons of the lateral hypothalamic area (LHA), exhibit context-dependent neural responses to food rewards and aversive stimuli, and confer contextual and internal state-dependent calibration of feeding. Viral deletion of Pdyn in the DLS impaired context-dependent food reward consumption, suggesting a role for dynorphin/kappa opioid receptor signaling in these processes. Together, our findings highlight how ancient LHA feeding circuits integrate DHPC input through DLS(Pdyn) inhibitory neurons to link context with regulation of food consumption.