Biology subjects

Gallo, E. F.

Publications and source records attributed to Gallo, E. F..

5 recordsLinked to original sources

bioRxiv2026

Nucleus accumbens acetylcholine dips track reward value and temporal costs to shape delay discounting

As an organism chooses between competing rewards, it must often integrate learned reward value with the changing costs associated with obtaining them. Yet, the brain mechanisms through which these factors jointly guide choice are not well understood. Previous studies have shown that dopamine signals in the nucleus accumbens (NAc) track reward value and are modulated by their associated delay costs. Our prior work further implicated NAc cholinergic interneurons by demonstrating that dopamine D2 receptors in these neurons influence choice under temporal, but not probabilistic, costs. However, whether NAc acetylcholine (ACh) dynamics track reward value and/or delay, and whether they contribute to adaptive choice, remains unknown. Using in vivo fiber photometry during a delay discounting task in which mice choose between a small, immediate reward and a larger, delayed reward, we reveal that cue-evoked ACh dips dynamically track relative reward magnitude and are diminished by increasing delays. Our data further show that optogenetically enhancing these dips attenuates the delay-dependent decline in choice of the larger, delayed reward. These findings identify a previously unrecognized role for NAc cue-evoked ACh dips in shaping adaptive choice as temporal costs increase.

neuroscience↗

bioRxiv2026

Ventral Pallidum Cholinergic Neurons Respond to Reward and Signal Reward Value

The ventral pallidum (VP) is a key basal ganglia structure involved in integrating reward-related signals to guide motivated behavior and feeding. VP neuronal activity is strongly tuned to reward-predictive cues and palatable rewards, tracking changes in value and motivational state. Recent studies have established important and opposing roles for GABAergic and glutamatergic VP neurons in reward- and avoidance-related behaviors. However, much less is known about the role of VP cholinergic neurons (VP-CNs), which comprise only [~]10% of VP neurons in mice, but maintain extensive connectivity with reward-related circuitry. Here, using cell type-selective in vivo fiber photometry during instrumental reward behavior, we found that VP-CN activity responds to cues, actions, and reward retrieval in a training-independent manner. Phasic VP-CN responses to reward retrieval were reduced by reward dilution, whereas pre-feeding with the reward enhanced these responses. In contrast, non-cholinergic VP neurons exhibited modulation by pre-feeding but not by reward dilution. Together, these findings identify VP-CNs as a distinct and dynamically regulated VP population whose activity is sensitive to both reward palatability and physiological state, extending our current understanding of the VP and its roles in reward processing.

neuroscience↗

bioRxiv2023

Egr1 is a sex-specific regulator of neuronal chromatin, synaptic plasticity, and behaviour

Sex differences are found in brain structure and function across species, and across brain disorders in humans1-3. The major source of brain sex differences is differential secretion of steroid hormones from the gonads across the lifespan4. Specifically, ovarian hormones oestrogens and progesterone are known to dynamically change structure and function of the adult female brain, having a major impact on psychiatric risk5-7. However, due to limited molecular studies in female rodents8, very little is still known about molecular drivers of female-specific brain and behavioural plasticity. Here we show that overexpressing Egr1, a candidate oestrous cycle-dependent transcription factor9, induces sex-specific changes in ventral hippocampal neuronal chromatin, gene expression, and synaptic plasticity, along with hippocampus-dependent behaviours. Importantly, Egr1 overexpression mimics the high-oestrogenic phase of the oestrous cycle, and affects behaviours in ovarian hormone-depleted females but not in males. We demonstrate that Egr1 opens neuronal chromatin directly across the sexes, although with limited genomic overlap. Our study not only reveals the first sex-specific chromatin regulator in the brain, but also provides functional evidence that this sex-specific gene regulation drives neuronal gene expression, synaptic plasticity, and anxiety- and depression-related behaviour. Our study exemplifies an innovative sex-based approach to studying neuronal gene regulation1 in order to understand sex-specific synaptic and behavioural plasticity and inform novel brain disease treatments.

neuroscience↗

bioRxiv2023

Dopamine D2 receptors in nucleus accumbens cholinergic interneurons increase impulsive choice

Impulsive choice, often characterized by excessive preference for small, short-term rewards over larger, long-term rewards, is a prominent feature of substance use and other neuropsychiatric disorders. The neural mechanisms underlying impulsive choice are not well understood, but growing evidence implicates nucleus accumbens (NAc) dopamine and its actions on dopamine D2 receptors (D2Rs). Because several NAc cell types and afferents express D2Rs, it has been difficult to determine the specific neural mechanisms linking NAc D2Rs to impulsive choice. Of these cell types, cholinergic interneurons (CINs) of the NAc, which express D2Rs, have emerged as key regulators of striatal output and local dopamine release. Despite these relevant functions, whether D2Rs expressed specifically in these neurons contribute to impulsive choice behavior is unknown. Here, we show that D2R upregulation in CINs of the mouse NAc increases impulsive choice as measured in a delay discounting task without affecting reward magnitude sensitivity or interval timing. Conversely, mice lacking D2Rs in CINs showed decreased delay discounting. Furthermore, CIN D2R manipulations did not affect probabilistic discounting, which measures a different form of impulsive choice. Together, these findings suggest that CIN D2Rs regulate impulsive decision-making involving delay costs, providing new insight into the mechanisms by which NAc dopamine influences impulsive behavior.

neuroscience↗

bioRxiv2020

Dopamine D2 receptors modulate the cholinergic pause and inhibitory learning

Cholinergic interneurons (CINs) in the striatum respond to salient stimuli with a multiphasic response, including a pause, in neuronal activity. Slice physiology experiments have shown the importance of dopamine D2 receptors (D2Rs) in regulating CIN pausing yet the behavioral significance of the CIN pause and its regulation by dopamine in vivo is still unclear. Here, we show that D2R upregulation in CINs of the nucleus accumbens (NAc) lengthens the pause in CIN activity ex vivo and enlarges a stimulus-evoked decrease in acetylcholine (ACh) levels during behavior. This enhanced dip in ACh levels is associated with a selective deficit in the learning to inhibit responding in a Go/No-Go task. Our data demonstrate, therefore, the importance of CIN D2Rs in modulating the CIN response induced by salient stimuli and points to a role of the pause in inhibitory learning. This work has important implications for brain disorders with altered striatal dopamine and ACh function, including schizophrenia and attention-deficit hyperactivity disorder (ADHD).

neuroscience↗