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Bordieanu, B.

Publications and source records attributed to Bordieanu, B..

4 recordsLinked to original sources

Cortical astrocytes flexibly encode reward contingencies and shape conditioned behavior

Learned associations between environmental cues and reward drive motivated behavior, yet how specific cell types support this process remains unclear. Using longitudinal two-photon calcium imaging, we tracked dorsal medial prefrontal cortical astrocytes throughout the acquisition, expression, and reversal of Pavlovian sucrose conditioning. As learning progressed, astrocytes exhibited time-locked, spatially coordinated calcium signals that differentiated correct behavioral action from mistakes, evolving from broad outcome encoding to selective representation of responses associated with the reward-conditioned stimulus. Omission testing revealed that prefrontal astrocytes preferentially respond to the cue-reward association, rather than the conditioned stimulus or reward alone. When reward contingencies were reversed, astrocytic activity rapidly adapted to track the new cue-reward association and encode updated and outdated motivated behavioral actions. Finally, astrocytic ablation attenuated motivated behavior during initial associative learning and prevented persistence of conditioned reward seeking when reward contingencies were updated or unpredictable. These findings reveal prefrontal astrocytes are functionally plastic elements that regulate reward-seeking behavior across associative learning. TeaserPrefrontal astrocytes flexibly encode the cue-reward associations that drive conditioned reward-seeking behavior.

neuroscience↗

Cannabis-enriched oral Actinomyces induces anxiety-like behavior via impairing mitochondria and GABA signaling

The human oral microbiome is increasingly recognized as a contributor to brain health, yet its mechanisms remain unclear. Our previous work revealed that oral Actinomyces species was enriched in chronic cannabis smokers. Here, we show oral inoculation of cannabis use-associated Actinomyces species, especially A. meyeri, to wild-type C57BL/6 mice leads to anxiety-like behaviors, non-region-specific microglia activation, mitochondrial dysfunction, and reduced GABAergic neurotransmission, without evidence of bacterial translocation to the brain, neuroinflammation, and memory decline. Notably, Actinomyces species-producing metabolites, i.e., arginine and argininosuccinate, were increased in both oral swabs and brain following inoculation in vivo. These Actinomyces species-producing metabolites induced mitochondrial dysfunction and oxidative stress in neurons in vitro, indicating a neuropathogenic role and aligning with reduced GABAergic neurotransmission in vivo. Together, these results suggest that oral cannabis-associated dysbiosis impacts behavior through mitochondrial stress and impaired inhibitory signaling, indicating the oral-brain metabolic axis is potentially consequential in neuropsychiatric disorders. TeaserChronic heavy cannabis use-enriched oral bacteria can drive anxiety and neuropathogenesis in mice. Highlights{whitebullet} Cannabis-associated oral Actinomyces enrichment induces anxiety-like behavior in mice {whitebullet}Microglial activation occurs without neuroinflammation (IL-1{beta}, TNF-, and IL-6) {whitebullet}Mitochondrial hyperactivation and reduced inhibitory GABAergic signaling Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=160 SRC="FIGDIR/small/689724v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@120b0b1org.highwire.dtl.DTLVardef@1304782org.highwire.dtl.DTLVardef@a6aa77org.highwire.dtl.DTLVardef@17d6d_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Corticostriatal ensemble dynamics across heroin self-administration to reinstatement

Corticostriatal projection neurons from prelimbic medial prefrontal cortex to the nucleus accumbens core critically regulate drug-seeking behaviors, yet the underlying encoding dynamics whereby these neurons contribute to drug seeking remain elusive. Here we use two-photon calcium imaging to visualize the activity of corticostriatal neurons in mice from the onset of heroin use to relapse. We find that the activity of these neurons is highly heterogeneous during heroin self-administration and seeking, with at least 8 distinct neuronal ensembles that display both excitatory and inhibitory encoding dynamics. These neuronal ensembles are particularly apparent during relapse, where excitatory responses are amplified compared to heroin self-administration. Moreover, we find that optogenetic inhibition of corticostriatal projection neurons attenuates heroin seeking regardless of the relapse trigger. Our results reveal the precise corticostriatal activity dynamics underlying drug-seeking behaviors and support a key role for this circuit in mediating relapse to drug seeking.

neuroscience↗

Vagus nerve stimulation (VNS) modulates synaptic plasticity in the rat infralimbic cortex via Trk-B receptor activation to reduce drug-seeking

Drugs of abuse cause changes in the prefrontal cortex (PFC) and associated regions that impair inhibitory control over drug-seeking. Breaking the contingencies between drug-associated cues and the delivery of the reward during extinction learning reduces relapse. Vagus nerve stimulation (VNS) has previously been shown to enhance extinction learning and reduce drug-seeking. Here we determined the effects of VNS-mediated release of brain-derived neurotrophic factor (BDNF) on extinction and cue-induced reinstatement in rats trained to self-administer cocaine. Pairing 10 days of extinction training with VNS facilitated extinction and reduced drug-seeking behavior during reinstatement. Rats that received a single extinction session with VNS showed elevated BDNF levels in the medial PFC as determined via an enzyme-linked immunosorbent assay (ELISA). Systemic blockade of Tropomyosin receptor kinase B (TrkB) receptors during extinction, via the TrkB antagonist ANA-12, decreased the effects of VNS on extinction and reinstatement. Whole-cell recordings in brain slices showed that cocaine self-administration induced alterations in the ratio of AMPA and NMDA receptor-mediated currents in layer 5 pyramidal neurons of the infralimbic cortex (IL). Pairing extinction with VNS reversed cocaine-induced changes in glutamatergic transmission by enhancing AMPAR currents, and this effect was blocked by ANA-12. Our study suggests that VNS consolidates extinction of drug-seeking behavior by reversing drug-induced changes in synaptic AMPA receptors in the IL, and this effect is abolished by blocking TrkB receptors during extinction, highlighting a potential mechanism for the therapeutic effects of VNS in addiction. Significance StatementExtinction training can reverse maladaptive neuroplasticity induced by drugs of abuse, but adjunct treatments are sought that can facilitate the process and consolidate the newly formed memories. Pairing extinction training with vagus nerve stimulation (VNS) facilitates extinction and reduces drug-seeking behavior during reinstatement. Here, we show that rats receiving a single extinction session with VNS exhibit elevated brain-derived neurotrophic factor (BDNF) levels in the medial prefrontal cortex (mPFC). We also demonstrate that VNS consolidates the extinction of drug-seeking behavior by reversing cocaine-induced changes in synaptic AMPA receptors in the infralimbic cortex (IL) of the mPFC. This effect is blocked by the TrkB antagonist ANA-12, emphasizing the role of BDNF and TrkB receptors in the therapeutic effects of VNS in addiction.

neuroscience↗