Biology subjects

Albeanu, D. F.

Publications and source records attributed to Albeanu, D. F..

3 recordsLinked to original sources

bioRxiv2018

Olfactory marker protein regulates refinement of the glomerular map

The olfactory glomerulus is the anatomical and functional unit of the olfactory bulb, defined by convergent input from olfactory sensory neuron (OSN) axons expressing the same type of odorant receptor (OR). A key marker of mature OSNs is the olfactory marker protein (OMP), whose deletion has been associated with deficits in OSN signal transduction and odor discrimination. Here, we have investigated glomerular odor responses and anatomical architecture in mice in which one or both alleles of OMP were replaced by the fluorescent synaptic activity reporter, synaptopHluorin (OMP+/- and OMP-/- mice, respectively). Functionally heterogeneous glomeruli, that is, ones with micro-domains with distinct odor responses were rare in OMP+/- mice, but occurred frequently in OMP-/- mice. Genetic targeting of single ORs revealed that these micro-domains arise from anomalous co-innervation of individual glomeruli by OSNs expressing different ORs. The glomerular mistargeting of OSNs in the absence of OMP is restricted to a local neighborhood of a few glomerular diameters. Our studies document functional heterogeneity in sensory input within individual glomeruli and uncover its anatomical correlate, revealing an unexpected role for OMP in the formation and refinement of the glomerular olfactory map.

neuroscience↗

bioRxiv2018

Mosaic representations of odors in the input and output layers of the mouse olfactory bulb

The elementary stimulus features encoded by the olfactory system remain poorly understood. We examined the relationship between 1,666 physical-chemical descriptors of odors and the activity of olfactory bulb inputs as well as outputs in awake mice. Glomerular and M/T cell responses were sparse and locally heterogeneous, with only a coarse dependence of glomerular positions on physical-chemical properties. Odor features represented by ensembles of M/T cells were overlapping, but distinct from those represented in glomeruli, consistent with extensive interplay between feedforward and feedback inputs to the bulb. This reformatting was well-described as a rotation in odor space. The descriptors accounted for a small fraction in response variance, and the similarity of odors in physical-chemical space was a poor predictor of similarity in neuronal representations. Our results suggest that commonly used physical-chemical properties are not systematically represented in bulbar activity and encourage further search for better descriptors of odor space.

neuroscience↗

bioRxiv2017

A High Resolution Whole Brain Imaging Using Oblique Light Sheet Tomography

Present light sheet fluorescence microscopes lack the wherewithal to image the whole brain (large tissues) with uniform illumination/detection parameters and high enough resolution to provide an understanding of the various aspects of neuroanatomy. To overcome this, we developed an oblique version of the light sheet microscope (Oblique Light Sheet Tomography, OLST) that includes a high magnification objective and serial sectioning, for volumetric imaging of the whole mouse brain at high spatial resolution at constant illumination/detection. We developed a novel gelatin based re-embedding procedure that makes the cleared brain rigid so that it can sectioned using our integrated microtome. Here, we characterize OLST and show that it can be used to observe dendritic morphology, spines and follow axons over a few mm in the mouse brain.

neuroscience↗