Brief Sensory Deprivation Triggers Cell Type-Specific Structural and Functional Plasticity in Olfactory Bulb Neurons.

Can alterations in experience trigger different plastic modifications in neuronal structure and function, and if so, how do they integrate at the cellular level? To address this question, we interrogated circuitry in the mouse olfactory bulb responsible for the earliest steps in odor processing. We induced experience-dependent plasticity in mice of either sex by blocking one nostril for one day, a minimally invasive manipulation that leaves the sensory organ undamaged and is akin to the natural transient blockage suffered during common mild rhinal infections. We found that such brief sensory deprivation produced structural and functional plasticity in one highly specialized bulbar cell type: axon-bearing dopaminergic neurons in the glomerular layer. After 24 h naris occlusion, the axon initial segment (AIS) in bulbar dopaminergic neurons became significantly shorter, a structural modification that was also associated with a decrease in intrinsic excitability. These effects were specific to the AIS-positive dopaminergic subpopulation because no experience-dependent alterations in intrinsic excitability were observed in AIS-negative dopaminergic cells. Moreover, 24 h naris occlusion produced no structural changes at the AIS of bulbar excitatory neurons, mitral/tufted and external tufted cells, nor did it alter their intrinsic excitability. By targeting excitability in one specialized dopaminergic subpopulation, experience-dependent plasticity in early olfactory networks might act to fine-tune sensory processing in the face of continually fluctuating inputs.SIGNIFICANCE STATEMENT Sensory networks need to be plastic so they can adapt to changes in incoming stimuli. To see how cells in mouse olfactory circuits can change in response to sensory challenges, we blocked a nostril for just one day, a naturally relevant manipulation akin to the deprivation that occurs with a mild cold. We found that this brief deprivation induces forms of axonal and intrinsic functional plasticity in one specific olfactory bulb cell subtype: axon-bearing dopaminergic interneurons. In contrast, intrinsic properties of axon-lacking bulbar dopaminergic neurons and neighboring excitatory neurons remained unchanged. Within the same sensory circuits, specific cell types can therefore make distinct plastic changes in response to an ever-changing external landscape

Imidazol-1-ylethylindazole Voltage-Gated Sodium Channel Ligands Are Neuroprotective during Optic Neuritis in a Mouse Model of Multiple Sclerosis

[Image: see text] A series of imidazol-1-ylethylindazole sodium channel ligands were developed and optimized for sodium channel inhibition and in vitro neuroprotective activity. The molecules exhibited displacement of a radiolabeled sodium channel ligand and selectivity for blockade of the inactivated state of cloned neuronal Na(v) channels. Metabolically stable analogue 6 was able to protect retinal ganglion cells during optic neuritis in a mouse model of multiple sclerosis

Protocol for Patch-Seq of Small Interneurons

Obtaining electrophysiological recordings and gene expression information from the same neuron (Patch-seq) brings forward a unique opportunity to study the transcriptional correlates of functional properties and vice versa. Here, we provide a detailed Patch-seq protocol tailored to the specialized demands of studying small interneurons. Focusing on the technically demanding process of transitioning between patch recordings and cell extraction, our protocol describes and troubleshoots steps for successfully collecting small interneurons, allowing for multi-modal Patch-seq interrogation of this crucial cell type.</p

Data from Rapid presynaptic maturation in naturally regenerating axons of the adult mouse olfactory nerve

All raw data and analysis from Browne et al. 'Rapid presynaptic maturation in naturally regenerating axons of the adult mouse olfactory nerve' Cell Reports 41:111750 https://doi.org/10.1016/j.celrep.2022.111750 Includes image files (Zeiss .lsm), exported text files from electrophysiological recordings (.xls/.csv), matlab analysis scripts (.m; note scripts for image analysis of glomerular coverage are in the 'Figure 1' folder, with usage instructions), and statistical analyses (Prism .pzf). All data are summarised in the stand-alone 'Cell reports data file.xlsx' spreadsheet

Rapid presynaptic maturation in naturally regenerating axons

AbstractSuccessful neuronal regeneration requires the re-establishment of synaptic connectivity. Crucial to this process is the reconstitution of presynaptic machinery responsible for controlling neurotransmitter release. In the mammalian adult CNS post-injury regeneration is usually only possible after extensive experimental intervention, and it is unknown how presynaptic function is re-established, let alone how it might be optimised to promote functional recovery. Here we addressed these questions by studying presynaptic maturation during a regenerative process that occurs entirely naturally. After toxin-induced injury, olfactory sensory neurons in the adult mouse olfactory epithelium can regenerate fully, sending axons to the brain to re-establish synaptic contact with postsynaptic partners in the olfactory bulb. Using electrophysiological recordings in acute slices, we found that after initial re-contact, functional connectivity in this system was rapidly established. Moreover, re-connecting presynaptic terminals had almost mature functional properties, including high release probability and a strong capacity for presynaptic inhibition. Release probability then matured quickly, rendering re-established terminals functionally indistinguishable from controls just one week after initial contact. These data show that successful synaptic regeneration in the adult mammalian brain is not quite a ‘plug-and-play’ process; instead, almost-mature presynaptic terminals undergo a rapid phase of functional maturation to re-integrate into established target networks.</jats:p

Data from Rapid presynaptic maturation in naturally regenerating axons of the adult mouse olfactory nerve

All raw data and analysis from Browne et al. 'Rapid presynaptic maturation in naturally regenerating axons of the adult mouse olfactory nerve' Cell Reports 41:111750 https://doi.org/10.1016/j.celrep.2022.111750 Includes image files (Zeiss .lsm), exported text files from electrophysiological recordings (.xls/.csv), matlab analysis scripts (.m; note scripts for image analysis of glomerular coverage are in the 'Figure 1' folder, with usage instructions), and statistical analyses (Prism .pzf). All data are summarised in the stand-alone 'Cell reports data file.xlsx' spreadsheet.</p