Biology subjects

Bartas, K.

Publications and source records attributed to Bartas, K..

5 recordsLinked to original sources

bioRxiv2024

Molecular and circuit determinants in the globus pallidus mediating control of cocaine-induced behavioral plasticity

The globus pallidus externus (GPe) is a central component of the basal ganglia circuit, receiving strong input from the indirect pathway and regulating a variety of functions, including locomotor output and habit formation. We recently showed that it also acts as a gatekeeper of cocaine-induced behavioral plasticity, as inhibition of parvalbumin-positive cells in the GPe (GPePV) prevents the development of cocaine-induced reward and sensitization. However, the molecular and circuit mechanisms underlying this function are unknown. Here we show that GPePV cells control cocaine reward and sensitization by inhibiting GABAergic neurons in the substantia nigra pars reticulata (SNrGABA), and ultimately, selectively modulating the activity of ventral tegmental area dopamine (VTADA) cells projecting to the lateral shell of the nucleus accumbens (NAcLat). A major input to GPePV cells is the indirect pathway of the dorsomedial striatum (DMSD2), which receives DAergic innervation from collaterals of VTADA[->]NAcLat cells, making this a closed-loop circuit. Cocaine likely facilitates reward and sensitization not directly through actions in the GPe, but rather in the upstream DMS, where the cocaine-induced elevation of DA triggers a depression in DMSD2 cell activity. This cocaine-induced elevation in DA levels can be blocked by inhibition of GPePV cells, closing the loop. Interestingly, the level of GPePV cell activity prior to cocaine administration is correlated with the extent of reward and sensitization that animals experience in response to future administration of cocaine, indicating that GPePV cell activity is a key predictor of future behavioral responses to cocaine. Single nucleus RNA-sequencing of GPe cells indicated that genes encoding voltage-gated potassium channels KCNQ3 and KCNQ5 that control intrinsic cellular excitability are downregulated in GPePV cells following a single cocaine exposure, contributing to the elevation in GPePV cell excitability. Acutely activating channels containing KCNQ3 and/or KCNQ5 using the small molecule carnosic acid, a key psychoactive component of Salvia rosmarinus (rosemary) extract, reduced GPePV cell excitability and also impaired cocaine reward, sensitization, and volitional cocaine intake, indicating its potential as a therapeutic to counteract psychostimulant use disorder. Our findings illuminate the molecular and circuit mechanisms by which the GPe orchestrates brain-wide changes in response to cocaine that are required for reward, sensitization, and self-administration behaviors.

neuroscience↗

bioRxiv2024

Analysis of changes in inter-cellular communications during Alzheimer's Disease pathogenesis reveals conserved changes in glutamatergic transmission in mice and humans

Analysis of system-wide cellular communication changes in Alzheimers disease (AD) has recently been enabled by single nucleus RNA sequencing (snRNA-seq) and new computational methods. Here, we combined these to analyze data from postmortem human tissue from the entorhinal cortex of AD patients and compared our findings to those from multiomic data from the 5xFAD amyloidogenic mouse model at two different time points. Using the cellular communication inference tool CellChat we found that disease-related changes were largely related to neuronal excitability as well as synaptic communication, with specific signaling pathways including BMP, EGF, and EPHA, and relatively poor conservation of glial-related changes during disease. Further analysis using the neuron-specific NeuronChat revealed changes relating to metabotropic glutamate receptors as well as neuronal adhesion molecules including neurexins and neuroligins. Our results that cellular processes relating to excitotoxicity are the best conserved between 5xFAD mice and AD suggest that excitotoxicity is the main common feature between pathogenesis in 5xFAD mice and AD patients.

neuroscience↗

bioRxiv2024

Neural circuit basis of adolescent THC-induced potentiation of opioid responses in adult mice

Use of one drug of abuse typically influences the behavioral response to other drugs, either administered at the same time or a subsequent time point. The nature of the drugs being used, as well as the timing and dosing, also influence how these drugs interact. Here, we tested the effects of adolescent THC exposure on the development of morphine-induced behavioral adaptations following repeated morphine exposure during adulthood. We found that adolescent THC administration potentiated reward, and paradoxically impaired the development of morphine reward. Following a forced abstinence period, we then mapped the whole-brain response to a moderate dose of morphine, and found that adolescent THC administration led to increased morphine-induced activity in the basal ganglia and increased functional connectivity between frontal cortical regions and the ventral tegmental area. Last, we show using rabies virus-based circuit mapping that adolescent THC exposure triggers a long-lasting elevation in connectivity from the frontal cortex regions onto ventral tegmental dopamine cells. Our study adds to the rich literature on the interaction between drugs of abuse, including THC and opioids, and provides potential circuit substates by which adolescent THC exposure influences responses to morphine later in life.

neuroscience↗

bioRxiv2022

Mapping long-term changes in inputs to the ventral tegmental area after a single drug exposure

Addictive drugs cause long-lasting changes in connectivity from inputs onto ventral tegmental area dopamine cells (VTADA) that contribute to drug-induced behavioral adaptations. However, it is not known which inputs are altered. Here we used a rabies virus (RABV)-based mapping strategy to quantify RABV-labeled inputs to VTA cells after a single exposure to one of a variety of misused drugs - cocaine, amphetamine, methamphetamine, morphine, and nicotine - and compared the relative global input labeling across conditions. We observed that all tested addictive drugs elicited similar input changes onto VTADA cells, in particular onto DA cells projecting to the lateral shell of the nucleus accumbens and amygdala. In addition, repeated administration of ketamine/xylazine to induce anesthesia induces a change in inputs to VTADA cells that is similar to but different from those elicited by a single exposure to addictive drugs, suggesting that caution should be taken when using ketamine/xylazine-based anesthesia in rodents when assessing motivated behaviors. Furthermore, comparison of viral tracing data to an atlas of gene expression in the adult mouse brain showed that the basal expression patterns of several gene classes, especially calcium channels, were highly correlated with the extent of both addictive drug- or ketamine/xylazine-induced changes in RABV-labeled inputs to VTADA cells. Reducing expression levels of the voltage-gated calcium channel Cacna1e in cells in the nucleus accumbens lateral shell reduced RABV-mediated input labeling of these cells into VTADA cells. These results directly link genes controlling cellular excitability and the extent of input labeling by RABV.

neuroscience↗

bioRxiv2021

An extended amygdala-midbrain circuit controlling cocaine withdrawal-induced anxiety and reinstatement

While midbrain dopamine (DA) neuronal circuits are central to motivated behaviors, much remains unknown about our knowledge of how these circuits are modified over time by experience to facilitate selective aspects of experience-dependent plasticity. Most studies of the DA system in drug addiction focus on the role of the mesolimbic DA pathway from the ventral tegmental area (VTA) to the nucleus accumbens (NAc) in facilitating drug-associated reward. In contrast, less is known about how midbrain DA cells and associated circuits contribute to negative affective states including anxiety that emerge during protracted withdrawal from drug administration. Here, we demonstrate the selective role of a midbrain DA projection to the amygdala (VTADA[->]Amygdala) for anxiety that develops during protracted withdrawal from cocaine administration but does not participate in cocaine reward or sensitization. Our rabies virus-mediated circuit mapping approach revealed a persistent elevation in spontaneous and task-related activity of GABAergic cells from the bed nucleus of the stria terminals (BNST) and downstream VTADA[->]Amygdala cells that could be detected even after a single cocaine exposure. Activity in BNSTGABA cells was related to cocaine-induced anxiety but not reward or sensitization, and silencing the projection from these cells to the midbrain was sufficient to prevent the development of anxiety during protracted withdrawal following cocaine administration. We observed that VTADA[->]Amygdala cells, but not other midbrain DA cells, were strongly activated after a challenge exposure to cocaine, and found that activity in these cells was necessary for the expression of reinstatement of cocaine place preference. Lastly, the importance of activity in VTADA[->]Amygdala cells extends beyond cocaine, as these cells mediate the development of anxiety states triggered by morphine and a predator odor. Our results provide an exemplar for how to identify key circuit substrates that contribute to behavioral adaptations and reveal a critical role for BNSTGABA[->]VTADA[->]Amygdala pathway in anxiety states induced by drugs of abuse or natural experiences as well as cocaine-primed reinstatement of conditioned place preference.

neuroscience↗