Projection neurons are necessary for the maintenance, but not for the assembly, of the mouse olfactory circuit

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: Aug. 15, 2023

ABSTRACT The assembly and maintenance of neural circuits is crucial for proper brain function. Although the has been extensively studied, much less understood about mechanisms controlling their as animals mature. In olfactory system, axons sensory neurons (OSNs) expressing same odor receptor converge into discrete synaptic structures bulb (OB) called glomeruli, forming a stereotypic map. OB projection neurons, mitral tufted cells (M/Ts), have single dendrite that branches glomerulus, where they make synapses with OSNs. We used genetic method to progressively eliminate vast majority M/T in early postnatal mice, observed proceeded normally. However, became adults apical remaining M/Ts grew multiple innervated several OSNs receptors projected disrupting Moreover, ablating adult also resulted similar structural changes projections from Interestingly, ability these mice detect odors was relatively preserved despite only having 1-5% transmitting odorant information brain, highly disrupted OB. These results indicate reduced number does not affect normal circuit, but induces instability circuitry animals.

Language: Английский

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Dense and persistent odor representations in the olfactory bulb of awake mice

Journal of Neuroscience, Journal Year: 2024, Volume and Issue: 44(39), P. e0116242024 - e0116242024

Published: Aug. 26, 2024

Recording and analysis of neural activity are often biased toward detecting sparse subsets highly active neurons, masking important signals carried in low-magnitude variable responses. To investigate the contribution seemingly noisy to odor encoding, we used mesoscale calcium imaging from mice both sexes record responses dorsal surface bilateral olfactory bulbs (OBs). The outer layer mouse OB is comprised dendrites organized into discrete "glomeruli," which defined by receptor-specific sensory neuron input. We extracted a large population glomeruli logistic regression classify odors individual trials with high accuracy. then add-in dropout analyses determine necessary sufficient for classification. Classifiers successfully predicted identity even after excluding sparse, glomeruli, indicating that information redundantly represented across glomeruli. Additionally, found random forest (RF) feature selection informed Gini inequality (RF impurity, RFGI) reliably ranked their overall RFGI provided measure "feature importance" each glomerulus correlated intuitive features like response magnitude. Finally, agreement previous work, persists glomerular offset. Together, our findings support model coding where identification, but widely, available representing about more than one odor.

Language: Английский

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Projection neurons are necessary for the maintenance of the mouse olfactory circuit

Published: Oct. 28, 2024

The assembly and maintenance of neural circuits is crucial for proper brain function. Although the has been extensively studied, much less understood about mechanisms controlling their as animals mature. In olfactory system, axons sensory neurons (OSNs) expressing same odor receptor converge into discrete synaptic structures bulb (OB) called glomeruli, forming a stereotypic map. OB projection neurons, mitral tufted cells (M/Ts), have single dendrite that branches glomerulus, where they make synapses with OSNs. We used genetic method to progressively eliminate vast majority M/T in early postnatal mice, observed proceeded normally. However, became adults apical remaining M/Ts grew multiple innervated several OSNs receptors projected disrupting Moreover, ablating adult also resulted similar structural changes projections from Interestingly, ability these mice detect odors was relatively preserved despite only having 1-5% transmitting odorant information brain, highly disrupted OB. These results indicate reduced number does not affect normal circuit, but induces instability circuitry animals.

Language: Английский

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Projection neurons are necessary for the maintenance of the mouse olfactory circuit

eLife, Journal Year: 2024, Volume and Issue: 13

Published: Dec. 13, 2024

The assembly and maintenance of neural circuits is crucial for proper brain function. Although the has been extensively studied, much less understood about mechanisms controlling their as animals mature. In olfactory system, axons sensory neurons (OSNs) expressing same odor receptor converge into discrete synaptic structures bulb (OB) called glomeruli, forming a stereotypic map. OB projection neurons, mitral tufted cells (M/Ts), have single dendrite that branches glomerulus, where they make synapses with OSNs. We used genetic method to progressively eliminate vast majority M/T in early postnatal mice, observed proceeded normally. However, became adults apical remaining M/Ts grew multiple innervated several OSNs receptors projected disrupting Moreover, ablating adult also resulted similar structural changes projections from Interestingly, ability these mice detect odors was relatively preserved despite only having 1–5% transmitting odorant information brain, highly disrupted OB. These results indicate reduced number does not affect normal circuit, but induces instability circuitry animals.

Language: Английский

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Odor and reward-evoked GABAergic neuronal activity in the basal forebrain influences olfactory-guided behavior in mice

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2022, Volume and Issue: unknown

Published: Sept. 4, 2022

ABSTRACT Sensory perception relies on the flexible detection and interpretation of stimuli across variable contexts, conditions, behavioral states. The basal forebrain is a hub for state regulation, supplying dense cholinergic GABAergic projections to various brain regions involved in sensory processing. Of neurons forebrain, parvalbumin (PV) somatostatin (SST) subtypes serve opposing roles towards regulating To elucidate role circuits sensory-guided behavior, we investigated signaling dynamics during odor-guided decision-making. We used fiber photometry record cell type-specific activity an odor discrimination task correlated temporal patterns PV SST neuronal with olfactory performance. found that while both PV-expressing SST-expressing were activated by odors, selectively suppressed reward whereas activated. Notably, chemogenetic inhibition BF modestly altered decision bias favor reward-seeking optogenetic presentations improved accuracy. Together, these results suggest bidirectional neuron distinctly influence decision-making guided behavior. SIGNIFICANCE STATEMENT This study reveals distinct Fiber shows parvalbumin-expressing are rewards, somatostatin-expressing activated, establishing unique recruitment reinforcement. Chemogenetic interventions demonstrate divergent behavior perception. research provides new insights into how shape

Language: Английский

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