Topic: olfactory sensory neurons

Animals identify odors based on the combinatorial activation of olfactory sensory neurons having distinct chemical receptive fields. However, as the dose response of any olfactory sensory neuron is believed to follow a sigmoidal function that grows monotonically until it reaches a plateau, the subset of olfactory sensory neurons activated by an odor is expected to scale up with the odor concentration, undercutting the efficiency of combinatorial coding. Here we show that olfactory sensory neurons can in fact undergo a silent state upon strong and prolonged excitation called depolarization bloc

Odors evoke distinct patterns of neural activity across different concentrations, both at the input level of olfactory sensory neurons (OSN) and glomeruli, as well as the next level, mitral/tufted cells (MTCs). What features of these patterns carry invariant information about odor identity and what are the neural mechanisms defining these features? To address this question, we designed an all-optical system to monitor the activity of many glomeruli and MT cells with high temporal resolution and developed an optogenetic method for establishing functional connectivity between glomeruli and MTCs.

Vision plays a crucial role in instructing the brain’s spatial navigation systems. In the absence of vision, the remaining sensory systems attempt to fill in the previously dominated role of vision. However, how the brain’s navigational system is affected, as well as the strategies it adapts to facilitate spatial awareness following vision loss remains an open question. To explore this, we recorded from head direction (HD) cells in the anterior dorsal nucleus (ADn) of the thalamus in freely moving sighted and blind animals. First, we found that both congenitally blind and late-onset blind anim

The functional logic of brain circuits of Drosophila neuropils is largely determined by local/intrinsic neurons. The architecture of the antennal lobe (AL), for example, is numerically dominated by its local neurons (LNs) that interact with olfactory sensory neurons (OSNs) and projection neurons (PNs) within and across glomeruli. Detailed connectomic data, e.g., the Hemibrain dataset, reveal a massive number of nested feedback loops among these three classes of neurons. Dissecting the role of these feedback circuits is key to the understanding the computation taking place in AL and beyond. How

Olfactory sensory neurons (OSNs) detect odours at a wide range of intensities. In insects, volatile compounds are perceived by odorant receptors (ORs), which are made up of an odour-specific protein (OrX) and the ubiquitous odorant co-receptor Orco. In principle, ORs tune the sensitivity of odour detection, with some OSNs exhibiting exceptionally high sensitivity. To test whether additional mechanisms underlie odour-specific neuronal processing, we investigated synapses between OSNs and projection neurons in the antennal lobe, the first relay station of the olfactory pathway. Here, we studied

Successful recovery after nervous system injury requires not only the restoration of damaged projections, but also appropriate processing of restored input by downstream circuits. How do target circuits adapt to such conditions of denervation and re-innervation? Might they undergo adaptive plastic modifications that promote functional repair and recovery? We addressed these questions by studying a unique model of naturally occurring regeneration in the adult mammalian brain. After a single dose of the olfactotoxin methimazole, olfactory sensory neurons in the nasal olfactory epithelium degener

Promoting adult neurogenesis in aging has the potential to rejuvenate neural circuits and restore associated functions. Establishing tractable models of adult neurogenesis can significantly expedite the identification of compounds and their cellular mechanisms promoting nervous system regeneration in aging. We have established the fruit fly Drosophila melanogaster as an easily scalable, highly tractable and genetically conserved platform to analyze nervous system regeneration. Particularly, by developing and implementing genetically-encoded lineage tracing systems, as well as molecular and ima

Odor cues from distant objects are sparse and highly fluctuating due to turbulent transport. However, whether animals can use these spatiotemporally varying statistics for decision-making is unclear. To address this question, we built a custom olfactometer to deliver discrete and brief (~40 ms halfwidth) odor pulses at arbitrary Poisson-distributed pulse rates. We then developed a behavioral task in which head-restrained, water-restricted mice had to make binary decisions based on the total odor pulse count in 5 seconds to obtain a water reward (Figures A-B). Performance in the task approached

In the olfactory system, the glomeruli of the olfactory bulb define the first synapse processing odour information in the brain. Here, many synapses are established between olfactory sensory neurons (OSNs) and olfactory bulb neurons. Xenopus tropicalis tadpoles provide an excellent experimental platform to investigate the molecular mechanisms of synaptic transmission in vivo due to its experimental accessibility and transparency. We investigated long-lasting depolarizations (LLDs) occurring in the glomerular layer of the olfactory bulb by measuring changes in the local field potential. We reco

Changes in olfaction are emerging as early warning signs of several major neurological diseases. Neurological diseases are also associated with aberrant brain rhythms. Olfactory sensory neurons (OSN) deliver input from the nasal epithelium (NE) to the olfactory bulb (OB) and are key drivers of rhythmicity. Here, we examine the role of sensory input arising from the NE in the generation of electrophysiological rhythms in the OB. Rats were implanted with electrodes in the OB and post-surgery gadolinium/saline was infused bilaterally to both nares. Olfactory function was assessed using the hidden