Biology subjects

Huda, R.

Publications and source records attributed to Huda, R..

11 recordsLinked to original sources

bioRxiv2026

A Low-Cost, Modular Hardware and Software Platform for Head-Fixed Mouse Decision-Making Tasks

Head-fixed behavior in rodents is a foundational technique in systems neuroscience which enables use of sophisticated imaging techniques in combination with animal behavior. However, accessibility of head-fixed behavior techniques is limited. Animal training consumes a large amount of experimenter labor and commercial setups, when available, are largely inflexible and financially burdensome. Here, we present a low-cost, modular, and open-source hardware and software implementation for head-fixed rodent decision-making tasks. Our design lowers experimenter labor and enables large teams of researchers to participate in animal training with minimal experimenter error using a simple touchscreen GUI and automated training progression. We demonstrate the efficacy of the platform by training a cohort of animals in a two-choice probabilistic rapid-reversal task in which mice continuously update action choices based on recent reward history. The presented design lowers the barrier to entry for laboratories seeking to conduct head-fixed rodent behavior and provides modular solutions for developing custom rigs based on experimental demands. Significance StatementHead-fixation in behaving rodents is a common neuroscience procedure that enables the use of electrical or optical techniques for neural circuit interrogation. While commercial head-fixed behavior platforms are available, their high cost and inflexibility make them unsuitable for modification or high-throughput training. This study presents a novel open-source hardware and software system for mouse head-fixed behavior. The modular design and use of low-cost components enable broad adaptability across behavioral tasks, compatibility with practical research demands, and significantly lowers the barrier to entry to head-fixed behavioral research.

neuroscience↗

bioRxiv2026

Striatal cholinergic and dopaminergic driven astrocyte Ca2+ activity is disrupted in Parkinsonian mice

Brain neuromodulatory systems exert powerful effects on local neuronal circuit function and behavior. In addition to classical actions directly on neurons, growing evidence indicates that neuromodulators also recruit Ca2+-dependent astrocyte mechanisms to regulate synaptic plasticity and network function. The dorsal striatum integrates cortical and thalamic inputs under strong dopamine (DA) and acetylcholine (ACh) neuromodulatory control. To what extent the circuit and behavioral effects of striatal ACh and DA depend on astrocyte Ca2+ activity remains unclear. We show that locomotion elicits robust DA, ACh, and astrocyte Ca2+ activity in the dorsolateral striatum (DLS). DA and ACh release exhibits a negative correlation on a fast time scale but shows a positive correlation during continuous locomotion as slower astrocyte Ca2+ activity builds. Higher ACh and DA release is associated with higher astrocyte events, suggesting that both neurotransmitters drive astrocyte activity. In agreement, pharmacological blockade of muscarinic ACh or D1/D2 DA receptors decreases locomotion-evoked astrocyte Ca2+. Closed-loop optogenetic inhibition of striatal cholinergic interneurons (CINs) during locomotion reduces astrocyte Ca2+ activity, demonstrating a causal contribution of ACh release to astrocyte activity. Locomotion related ACh release was severely compromised in a mouse model of Parkinsons disease (PD), with the dual loss of DA and ACh attenuating astrocyte Ca2+ activity. Facilitating astrocyte cholinergic signaling via chemogenetics improved both calcium activity and motor deficits in our recent work. Thus, the pathophysiology of PD in part involves attenuated astrocyte Ca2+ signaling, placing these non-neuronal cells as a prime underexplored therapeutic target for PD.

neuroscience↗

bioRxiv2026

Dorsal striatal circuit mechanisms contributing to astrocyte modulation of alcohol-related behaviors

BackgroundThe dorsolateral striatum (DLS) is a key site for coordinating the alcohol-induced stimulant response, a behavioral marker predictive of future alcohol use disorder. Although ethanol (EtOH) affects all brain cells, little is known about the contribution of non-neuronal DLS cell types to EtOH-induced stimulation. MethodsWe used ex vivo two photon calcium imaging, in vivo fiber photometry of astrocyte and neuronal GCaMP, and astrocyte-specific manipulations in mice to determine DLS astrocyte contributions to EtOH-induced stimulation and voluntary EtOH drinking behavior. Using fiber photometry of GRAB-ACh sensors and cell-type specific chemogenetics, we also assessed the role of cholinergic signaling in observed astrocyte EtOH effects. ResultsAs expected, intraperitoneal EtOH injections (0.5-2g/kg) evoked a stimulant response, evidenced by increased locomotion compared to saline. In parallel, EtOH dose-dependently decreased astrocyte calcium activity but had minimal effects on direct and indirect pathway neuronal activity. Mimicking this reduction with astrocyte-specific expression of CalEX, a calcium extruding pump, facilitated EtOH stimulation compared to mice expressing a control fluorophore. Hence, EtOH-induced suppression of DLS astrocyte activity contributes to stimulation. Astrocyte calcium signaling is a well-known target of neuromodulation. Fiber photometry recordings of extracellular acetylcholine (ACh) levels via GRAB-ACh imaging showed inhibition of ACh release by acute EtOH. We virally expressed the excitatory chemogenetic actuator hM3Dq in striatal cholinergic interneurons to assess whether artificially increasing ACh release blocks EtOH-induced inhibition of astrocytic calcium activity. Despite facilitating ACh release, this manipulation did not impact astrocyte calcium activity under control (saline) or EtOH conditions. Together, this work identifies DLS astrocytes as key contributors to EtOH-induced stimulation and highlights the importance of considering astrocyte-neuron interactions in evaluating alcohol effects.

neuroscience↗

bioRxiv2024

A cortical locus for modulation of arousal states

Fluctuations in global arousal are key determinants of spontaneous cortical activity and function. Several subcortical structures, including neuromodulatory nuclei like the locus coeruleus (LC), are involved in the regulation of arousal. However, much less is known about the role of cortical circuits that provide top-down inputs to arousal-related subcortical structures. Here, we investigated the role of a major subdivision of the prefrontal cortex, the anterior cingulate cortex (ACC), in arousal modulation. Pupil size, facial movements, heart rate, and locomotion were used as non-invasive measures of arousal and behavioral state. We designed a closed loop optogenetic system based on machine vision and found that real time inhibition of ACC activity during pupil dilations suppresses ongoing arousal events. In contrast, inhibiting activity in a control cortical region had no effect on arousal. Fiber photometry recordings showed that ACC activity scales with the magnitude of spontaneously occurring pupil dilations/face movements independently of locomotion. Moreover, optogenetic ACC activation increases arousal independently of locomotion. In addition to modulating global arousal, ACC responses to salient sensory stimuli scaled with the size of evoked pupil dilations. Consistent with a role in sustaining saliency-linked arousal events, pupil responses to sensory stimuli were suppressed with ACC inactivation. Finally, our results comparing arousal-related ACC and norepinephrinergic LC neuron activity support a role for the LC in initiation of arousal events which are modulated in real time by the ACC. Collectively, our experiments identify the ACC as a key cortical site for sustaining momentary increases in arousal and provide the foundation for understanding cortical-subcortical dynamics underlying the modulation of arousal states.

neuroscience↗

bioRxiv2024

Functional activation of dorsal striatum astrocytes improves movement deficits in hemi-parkinsonian mice

Parkinsons disease (PD) is characterized by the degeneration of dopaminergic nigrostriatal inputs, which causes striatal network dysfunction and leads to pronounced motor deficits. Recent evidence highlights astrocytes as a potential local source of striatal network modulation. However, it remains unknown how dopamine loss affects striatal astrocyte activity and whether astrocyte activity regulates behavioral deficits in PD. We addressed these questions by performing astrocyte-specific calcium recordings and manipulations using in vivo fiber photometry and chemogenetics. We find that locomotion elicits astrocyte calcium activity over a slower timescale than neurons. Unilateral dopamine depletion reduced locomotion-related astrocyte responses. Chemogenetic activation facilitated astrocyte activity, and improved asymmetrical motor deficits and open field exploratory behavior in dopamine lesioned mice. Together, our results establish a novel role for functional striatal astrocyte signaling in modulating motor function in PD and highlight non-neuronal targets for potential PD therapeutics.

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bioRxiv2023

Neuronal DAMPs exacerbate neurodegeneration via astrocytic RIPK3 signaling

Astrocyte activation is a common feature of neurodegenerative diseases. However, the ways in which dying neurons influence the activity of astrocytes is poorly understood. RIPK3 signaling has recently been described as a key regulator of neuroinflammation, but whether this kinase mediates astrocytic responsiveness to neuronal death has not yet been studied. Here, we used the MPTP model of Parkinsons disease to show that activation of astrocytic RIPK3 drives dopaminergic cell death and axon damage. Transcriptomic profiling revealed that astrocytic RIPK3 promoted gene expression associated with neuroinflammation and movement disorders, and this coincided with significant engagement of DAMP signaling. Using human cell culture systems, we show that factors released from dying neurons signal through RAGE to induce RIPK3-dependent astrocyte activation. These findings highlight a mechanism of neuron-glia crosstalk in which neuronal death perpetuates further neurodegeneration by engaging inflammatory astrocyte activation via RIPK3.

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bioRxiv2023

A paradigm for ethanol consumption in head-fixed mice during prefrontal cortical two-photon calcium imaging

The prefrontal cortex (PFC) is a hub for higher-level cognitive behaviors and is a key target for neuroadaptations in alcohol use disorders. Preclinical models of ethanol consumption are instrumental for understanding how acute and repeated drinking affects PFC structure and function. Recent advances in genetically encoded sensors of neuronal activity and neuromodulator release combined with functional microscopy (multiphoton and one-photon widefield imaging) allow multimodal in-vivo PFC recordings at subcellular and cellular scales. While these methods could enable a deeper understanding of the relationship between alcohol and PFC function/dysfunction, they require animals to be head-fixed. Here, we present a method in mice for binge-like ethanol consumption during head-fixation. Male and female mice were first acclimated to ethanol by providing home cage access to 20% ethanol (v/v) for 4 or 8 days. After home cage drinking, mice consumed ethanol from a lick spout during head-fixation. We used two-photon calcium imaging during the head-fixed drinking paradigm to record from a large population of PFC neurons (>1000) to explore how acute ethanol affects their activity. Drinking modulated activity rates in a subset of neurons on slow (minutes) and fast (seconds) time scales but the majority of neurons were unaffected. Moreover, ethanol intake did not significantly affect network level interactions in the PFC as assessed through inter-neuronal pairwise correlations. By establishing a method for binge-like drinking in head-fixed mice, we lay the groundwork for leveraging advanced microscopy technologies to study alcohol-induced neuroadaptations in PFC and other brain circuits. HighlightsO_LIC57BL/6J mice voluntarily consume ethanol to binge-like levels during head-fixation, with females consuming more ethanol than males. C_LIO_LIMice show differences in frontloading and licking behavior for head-fixed ethanol and sucrose consumption. C_LIO_LIHead-fixed paradigm enables two-photon calcium imaging in the anterior cingulate cortex subdivision of the prefrontal cortex. C_LIO_LIAcute ethanol increases and decreases single neuron activity at fast (seconds) and slow (minutes) time scales but does not alter pairwise correlations between neurons. C_LI

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bioRxiv2021

Multiplexed action-outcome representation by striatal striosome-matrix compartments detected with a novel cost-benefit foraging task

Learning about positive and negative outcomes of actions is crucial for survival and underpinned by conserved circuits including the striatum. How associations between actions and outcomes are formed is not fully understood, particularly when the outcomes have mixed positive and negative features. We developed a novel foraging ( bandit) task requiring mice to maximize rewards while minimizing punishments. By 2-photon Ca++ imaging, we monitored activity of 5831 identified anterodorsal striatal striosomal and matrix neurons. Surprisingly, we found that action-outcome associations for reward and punishment were combinatorially encoded rather than being integrated as overall outcome value. Single neurons could, for one action, encode outcomes of opposing valence. Striosome compartments consistently exhibited stronger representations of reinforcement outcomes than matrix, especially for high reward or punishment prediction errors. These findings demonstrate a remarkable multiplexing of action-outcome contingencies by single identified striatal neurons and suggest that striosomal neurons are differentially important in action-outcome learning.

neuroscience↗

bioRxiv2021

Voluntary alcohol consumption disrupts coupling of prefrontal cortical activity to arousal

Alcohol use disorder (AUD) exacts a major personal, societal, and economic toll. Top-down control from the prefrontal cortex (PFC), a critical hub for decision making, executive, and other cognitive functions, is key for the regulation of alcohol consumption. Arousal exerts profound effects on cortical processing, allowing it to potentially modulate PFC functions relevant for alcohol consumption and AUD. Despite this, it is unclear whether and how arousal-mediated modulation of PFC circuits relates to voluntary alcohol drinking behaviors. Two-photon microscopy is ideally suited for dissecting the neural circuit mechanisms underlying the effect of alcohol on intact circuits in behaving animals. We addressed a major limitation of this technology by developing a novel behavioral paradigm for voluntary drinking in head-fixed mice. We recorded responses of layer 2/3 excitatory neurons in the anterior cingulate cortex (ACC) subdivision of the PFC as mice voluntarily consumed ethanol, along with video recording of the pupil to track momentary fluctuations in arousal. Ethanol consumption bidirectionally modified the activity of subsets of ACC neurons, both at slow (minutes) and fast (sub-second) time scales. Remarkably, we found that the coupling of arousal to ACC activity before drinking was associated with subsequent ethanol engagement behavior. In turn, ethanol consumption modulated neuronal-arousal coupling. Together, our results suggest neuronal-arousal coupling as a key biomarker for alcohol drinking and lays the groundwork for future studies to dissect the therapeutic potential of this process for AUD and other substance use disorders.

neuroscience↗

bioRxiv2018

Bidirectional control of orienting behavior by distinct prefrontal circuits

Sensorimotor behaviors require processing of behaviorally relevant sensory cues and the ability to select appropriate responses from a vast behavioral repertoire. Top-down modulation by the prefrontal cortex (PFC) is thought to be key for both processes but the precise role of specific circuits remains unclear. We examined the sensorimotor function of anatomically distinct outputs from a subdivision of the mouse PFC, the anterior cingulate cortex (ACC). Using a visually guided two-choice behavioral paradigm with multiple cue-response mappings, we dissociated the sensory and motor response components of sensorimotor control. Projection-specific two-photon calcium imaging and optogenetic manipulations show that ACC outputs to the superior colliculus, a key midbrain structure for response selection, principally coordinate specific motor responses. Importantly, ACC outputs exert top-down control by reducing the innate response bias of the superior colliculus. In contrast, ACC outputs to the visual cortex facilitate sensory processing of visual cues. Our results ascribe motor and sensory roles to ACC projections to the superior colliculus and the visual cortex and demonstrate for the first time a circuit motif for PFC function wherein anatomically non-overlapping output pathways coordinate complementary but distinct aspects of visual sensorimotor behavior.

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bioRxiv2017

Two-Photon Imaging of Striatum Demonstrates Distinct Functions for Striosomes and Matrix in Reinforcement Learning

Despite the discovery of striosomes several decades ago, technical difficulties have hampered the study of their functions. Here we used 2-photon calcium imaging in neuronal birthdate-labeled Mash1-CreER mice to image simultaneously the activity of striosomal and matrix neurons in vivo. We report that with this method we can visually identify circumscribed zones of neuropil that correspond to striosomes as verified in immunostained sections. We find that striosomal neurons, relative to matrix neurons, preferentially encode reward-predicting cues, and that their activity contains more information about expected outcome. These characteristics emerge during training and further strengthen during overtraining. Both striatal compartments are active similarly after reward delivery, firing at neuron-specific times during or after consummatory licking. Finally, we find that immediate reward history strongly modulates neuronal activation in the next trial, especially in matrix neurons. These results suggest that striosomes and matrix have distinct functions in relation to reinforcement learning.

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