Biology subjects

Wozny, C.

Publications and source records attributed to Wozny, C..

4 recordsLinked to original sources

bioRxiv2024

Parvalbumin expression identifies subicular principal cells with high projection specificity

The calcium-binding protein parvalbumin is an established marker for a subset of cortical inhibitory interneurons with similar biophysical features and connectivity. However, parvalbumin is also expressed in a small population of excitatory cells in layer 5 of the neocortex with specific sub-cortical projection targets. Parvalbumin may thus also in principal cells identify particular subclasses with distinct connectivity and function. Here we investigated whether parvalbumin is expressed in excitatory neurons of the hippocampal formation and if so, whether it delineated neurons with specific features. We report parvalbumin-expressing glutamatergic cells in the distal subiculum, which -based on location, connectivity and gene expression - separated into two subclasses: neurons in deep layers, which specifically project to the antero-ventral thalamus and neurons in superficial layers, which project to the mamillary bodies. Contrary to most adjacent pyramidal cells parvalbumin-positive neurons were non-bursting and displayed straight apical dendrites devoid of oblique dendrites. Functionally, the projections diverged from classical driver/modulator subdivisions. Parvalbumin expression thus marks two sub-types of subicular projection neurons with high target specificity and unique functional features.

neuroscience↗

bioRxiv2022

Effects of early life stress and subsequent re-exposure to stress on neuronal activity in the lateral habenula

Early life stress can result in depression in humans and depressive-like behaviour in rodents. In various animal models of depression, the lateral habenula (LHb) has been shown to become hyperactive immediately after early life stress. However, whether these pathological changes persist into adulthood is less well understood. Hence, we utilised the maternal separation (MS) model of depression to study how early life stress alters LHb physiology and depressive behaviour in adult mice. We find that only a weak depressive phenotype persists into adulthood which surprisingly is underpinned by LHb hypoactivity in acute slices, accompanied by alterations in both excitatory and inhibitory signalling. However, while we find the LHb to be less active at rest, we report that the neurons reside in a sensitised state where they are more responsive to re-exposure to stress in adulthood in the form of acute restraint, thus priming them to respond to aversive events with an increase in neuronal activity mediated by changes in glutamatergic transmission. These findings thus suggest that in addition to LHb hyperactivity, hypoactivity likely also promotes an adverse phenotype. Re-exposure to stress results in the reappearance of LHb hyperactivity offering a possible mechanism to explain how depression relapses occur following previous depressive episodes.

neuroscience↗

bioRxiv2019

Disentangling neuronal inhibition and inhibitory pathways in the lateral habenula

The lateral habenula (LHb) is hyperactive in depression, and thus potentiating inhibition of this structure makes an interesting target for future antidepressant therapies. However, the circuit mechanisms mediating inhibitory signalling within the LHb are not well-known. We addressed this issue by studying LHb neurons expressing either parvalbumin (PV), neuron-derived neurotrophic factor (Ndnf) or somatostatin (SOM), three markers of particular sub-classes of neocortical inhibitory neurons. While we report that Ndnf is not representative of any particular sub-population of LHb neuron, we find that both PV and SOM are expressed by physiologically distinct sub-classes. Furthermore, we describe multiple sources of inhibitory input to the LHb arising from both local PV-positive neurons, and from PV-positive neurons in the medial dorsal thalamic nucleus, and from SOM-positive neurons in the ventral pallidum. These findings hence provide new insight into inhibitory control within the LHb, and highlight that this structure is more neuronally diverse than previously thought. SummaryThe lateral habenula receives inhibitory input from three distinct sources: from local PV-positive neurons, from PV-positive neurons in the medial dorsal thalamic nucleus (MDT); and from SOM-positive neurons in the ventral pallidum (VP). O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=178 SRC="FIGDIR/small/633271v2_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@8df117org.highwire.dtl.DTLVardef@cf226aorg.highwire.dtl.DTLVardef@dc94f5org.highwire.dtl.DTLVardef@1b76a7f_HPS_FORMAT_FIGEXP M_FIG C_FIG Significance statementThe circuitry by which inhibitory signalling is processed within the lateral habenula is currently not well understood; yet this is an important topic as inhibition of the lateral habenula has been shown to have antidepressant efficacy. We therefore investigated inhibitory signalling mechanisms within the lateral habenula by studying input neurons expressing markers commonly associated with inhibitory identity. We identity sources of inhibitory input from both local neurons, and arising from neurons in the medial dorsal thalamic nucleus and ventral pallidum. ContributionsJ.F.W. performed the experiments. R.V. contributed to experiments. J.F.W. analysed the data. K.B. and P.W. designed and performed the in situ hybridisation experiments. C.W. designed and supervised the study, and helped J.F.W write the manuscript. R.V. and S.S. contributed to the manuscript and discussions.

neuroscience↗

bioRxiv2018

VGLUT2 functions as a differential marker for hippocampal output neurons

The subiculum is the gatekeeper between the hippocampus and cortical areas. Yet, the lack of a pyramidal cell-specific marker gene has made the analysis of the subicular area very difficult. Here we report that the vesicular-glutamate transporter 2 (VGLUT2) functions as a specific marker gene for subicular burst-firing neurons, and demonstrate that VGLUT2-Cre mice allow for Channelrhodopsin-2 (ChR2)-assisted connectivity analysis.

neuroscience↗