Biology subjects

Cherasse, Y.

Publications and source records attributed to Cherasse, Y..

5 recordsLinked to original sources

bioRxiv2024

T-scope V4: miniaturized microscope for optogenetic tagging in freely behaving animals

A miniaturized microscope (i.e., miniscope) enables the imaging of neuronal activity using calcium sensors while simultaneously manipulating that activity using opsins in freely moving animals. However, many miniscopes use light-emitting diodes with broadband emission, leading to unintentional opsin stimulation by light intended solely for calcium sensor activation (a phenomenon referred to as "biological crosstalk"). To address this issue, we previously developed a miniscope including a port for chosen light sources, such as lasers, by restructuring the open-source UCLA Miniscope v3. However, targeting the same neuronal soma for both excitable opsin stimulation and calcium sensor imaging remained a challenge. Here, we integrated features from the UCLA Miniscope v4 into our new T-scope V4 miniscope. In optogenetic tagging experiments, we demonstrated that a 445-nm blue laser can be used to image neuronal activity with the calcium sensor GCaMP6s without inadvertently stimulating the ChrimsonR opsin, allowing for simultaneous neuronal activity imaging and manipulation in freely moving mice. Thus, the T-scope V4 can serve as a powerful tool for probing causal relationships between neuronal activity and its function in living animals. HighlightsO_LIWe developed the T-scope V4 that integrates features of the UCLA Miniscope v4 C_LIO_LIThis miniscope prevents "biological crosstalk" between sensors and opsins C_LIO_LIThis tool can help probe causal brain-behavior relationships in living animals C_LI

neuroscience↗

bioRxiv2023

Sequential Transitions of Male Sexual Behaviours Driven by Dual Acetylcholine-Dopamine Dynamics

The neural mechanisms regulating sequential transitions of male sexual behaviors, such as mounting, intromission, and ejaculation, in the brain remain unclear. Here, we report that dopamine (DA) and acetylcholine (ACh) dynamics in the ventral shell of the nucleus accumbens (vsNAc) closely aligns with serial transitions of sexual behaviors in male mice. During intromission, the vsNAc exhibits dual ACh-DA rhythms generated by reciprocal regulation between ACh and DA signaling via nicotinic acetylcholine (nAChR) and dopamine D2 (D2R) receptors. Knockdown of choline acetyl transferase (ChAT) or D2R in the vsNAc diminished the likelihood of intromission and ejaculation. Optogenetic manipulations reveal that DA signaling sustains male sexual behaviors by suppressing activities of D2RvsNAc neurons. Moreover, ACh signaling promotes the initiation of mounting and intromission, but also induces the intromission-to-ejaculation transition by triggering a slowdown of DA rhythm. Therefore, dual ACh-DA dynamics harmonize in the vsNAc to drive sequential transitions of male mating behaviors.

neuroscience↗

bioRxiv2023

The CaliAli tool for long-term tracking of neuronal population dynamics in calcium imaging

Neuron-tracking algorithms exhibit suboptimal performance in calcium imaging when the same neurons are not consistently detected, as unmatched features hinder intersession alignment. CaliAli addresses this issue by employing an alignment-before-extraction strategy that incorporates vasculature information to improve the detectability of weak signals and maximize the number of trackable neurons. By excelling in neural remapping and high spatial overlap scenarios, CaliAli paves the way toward further understanding long-term neural network dynamics.

neuroscience↗

bioRxiv2023

Activity of estrogen receptor beta expressing neurons in the medial amygdala regulates preference towards receptive females in male mice.

The processing of information regarding the sex and reproductive state of conspecific individuals is critical for successful reproduction and survival in males. Generally, male mice exhibit a preference towards sexually receptive (RF) over non-receptive females (XF) or gonadally intact males (IM). Previous studies suggested the involvement of estrogen receptor beta (ER{beta}) expressed in the medial amygdala (MeA) in male preference towards RF. To further delineate the role played by ER{beta} in the MeA in the neuronal network regulating male preference, we developed a new ER{beta}-iCre mouse line using the CRISPR-Cas9 system. Fiber-photometry Ca2+ imaging revealed that ER{beta} expressing neurons in the postero-dorsal part of the MeA (MeApd-ER{beta}+ neurons) were more active during social investigation towards RF compared to copresented XF or IM mice in a preference test. Chemogenetic inhibition of MeApd-ER{beta}+ neuronal activity abolished a preference to RF in "RF vs. XF", but not "RF vs. IM", tests. Analysis with cre-dependent retrograde tracing viral vectors identified the principal part of the bed nucleus of stria terminalis (BNSTp) as a primary projection site of MeApd-ER{beta}+ neurons. Fiber-photometry recording in the BNSTp during a preference test revealed that chemogenetic inhibition of MeApd-ER{beta}+ neurons abolished differential neuronal activity of BNSTp cells as well as a preference to RF against XF but not against IM mice. Collectively, these findings demonstrate for the first time that MeApd-ER{beta}+ neuronal activity is required for expression of receptivity-based preference (i.e., RF vs XF) but not sex-based preference (i.e., RF vs IM) in male mice. Significance StatementIn this study, by introducing a new Cre mice line for ER{beta}+ cells, we described the function of MeApd-ER{beta}+ neurons and characteristics of their neuronal activity during preference tests. Using fiber photometry and DREADD techniques we have found MeApd-ER{beta}+ neurons have a specific role in receptivity-based (receptive female vs. non-receptive female) preference but not in sexbased (receptive female vs. intact male) preference in male mice. We have also described this specific role of MeApd-ER{beta}+ neurons is achieved by regulating the neuronal activity of downstream BNSTp neurons during receptivity-based, but not sex-based, preference tests. Our findings contribute to a better understating of the function of estrogen receptor expressing neurons in the neuronal network for the male-typical reproductive behaviors.

neuroscience↗

bioRxiv2020

Chronic stress induces sex-specific functional and morphological alterations in cortico-accumbal and cortico-tegmental pathways.

BackgroundThe medial prefrontal cortex (mPFC) is part of a complex circuit controlling stress responses by sending projections to different limbic structures including the nucleus accumbens (NAc) and ventral tegmental area (VTA). However, the impact of chronic stress on NAc- and VTA-projecting mPFC neurons is still unknown and the distinct contribution of these pathways to stress responses in males and females is unclear. MethodsBehavioral stress responses were induced by 21 days of chronic variable stress (CVS) in male and female C57BL6 mice. An inter-sectional viral approach was used to label both pathways and assess the functional, morphological, and transcriptional adaptations in NAc- and VTA-projecting mPFC neurons in stressed males and females. Using chemogenetic approaches, we modified neuronal activity of NAc-projecting mPFC neurons to decipher their contribution to stress phenotypes. ResultsCVS induced depressive-like behaviors in males and females. NAc- and VTA-projecting mPFC neurons exhibited sex-specific functional, morphological, and transcriptional alterations. The functional changes were more severe in females in NAc-projecting mPFC neurons while males exhibited more drastic reductions in dendritic complexity in VTA-projecting mPFC neurons after CVS. Finally, chemogenetic overactivation of the cortico-accumbal pathway triggered anxiety and behavioral despair in both sexes while its inhibition rescued the phenotype only in females. ConclusionsOur results suggest that by changing the activity of transcriptional programs controlling neuronal plasticity, CVS interferes with the morphological and synaptic properties of the cortico-accumbal and tegmental pathways differently in males and females contributing to the expression of anxiety and depressive-like behaviors distinctly in a sex-specific fashion.

neuroscience↗