Dataset Information

Spectral unmixing: analysis of performance in the olfactory bulb in vivo.

ABSTRACT:

Background

The generation of transgenic mice expressing combinations of fluorescent proteins has greatly aided the reporting of activity and identification of specific neuronal populations. Methods capable of separating multiple overlapping fluorescence emission spectra, deep in the living brain, with high sensitivity and temporal resolution are therefore required. Here, we investigate to what extent spectral unmixing addresses these issues.

Methodology/principal findings

Using fluorescence resonance energy transfer (FRET)-based reporters, and two-photon laser scanning microscopy with synchronous multichannel detection, we report that spectral unmixing consistently improved FRET signal amplitude, both in vitro and in vivo. Our approach allows us to detect odor-evoked FRET transients 180-250 microm deep in the brain, the first demonstration of in vivo spectral imaging and unmixing of FRET signals at depths greater than a few tens of micrometer. Furthermore, we determine the reporter efficiency threshold for which FRET detection is improved by spectral unmixing.

Conclusions/significance

Our method allows the detection of small spectral variations in depth in the living brain, which is essential for imaging efficiently transgenic animals expressing combination of multiple fluorescent proteins.

SUBMITTER: Ducros M

PROVIDER: S-EPMC2635473 | biostudies-literature | 2009

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Spectral unmixing: analysis of performance in the olfactory bulb in vivo.

Ducros Mathieu M Moreaux Laurent L Bradley Jonathan J Tiret Pascale P Griesbeck Oliver O Charpak Serge S

PloS one 20090209 2

<h4>Background</h4>The generation of transgenic mice expressing combinations of fluorescent proteins has greatly aided the reporting of activity and identification of specific neuronal populations. Methods capable of separating multiple overlapping fluorescence emission spectra, deep in the living brain, with high sensitivity and temporal resolution are therefore required. Here, we investigate to what extent spectral unmixing addresses these issues.<h4>Methodology/principal findings</h4>Using fl ...[more]

PMID: 19198655

Similar Datasets

Project description:Here we present a detailed statistical analysis of the discharge characteristics of mitral cells of the main olfactory bulb of urethane-anesthetized rats. Neurons were recorded from the mitral cell layer, and antidromically identified by stimuli applied to the lateral olfactory tract. All mitral cells displayed repeated, prolonged bursts of action potentials typically lasting >100 sec and separated by similarly long intervals; about half were completely silent between bursts. No such bursting was observed in nonmitral cells recorded in close proximity to mitral cells. Bursts were asynchronous among even adjacent mitral cells. The intraburst activity of most mitral cells showed strong entrainment to the spontaneous respiratory rhythm; similar entrainment was seen in some, but not all nonmitral cells. All mitral cells displayed a peak of excitability at ~25 msec after spikes, as reflected by a peak in the interspike interval distribution and in the corresponding hazard function. About half also showed a peak at about 6 msec, reflecting the common occurrence of doublet spikes. Nonmitral cells showed no such doublet spikes. Bursts typically increased in intensity over the first 20-30 sec of a burst, during which time doublets were rare or absent. After 20-30 sec (in cells that exhibited doublets), doublets occurred frequently for as long as the burst persisted, in trains of up to 10 doublets. The last doublet was followed by an extended relative refractory period the duration of which was independent of train length. In cells that were excited by application of a particular odor, responsiveness was apparently greater during silent periods between bursts than during bursts. Conversely in cells that were inhibited by a particular odor, responsiveness was only apparent when cells were active. Extensive raw (event timing) data from the cells, together with details of those analyses, are provided as supplementary material, freely available for secondary use by others.

Project description:Olfactory sensory neurons distinguish a large variety of odor molecules and direct the information through their axons to the olfactory bulb, the first site for the processing of olfactory information in the brain. Olfaction is very important for most mammals for the maintenance of a good quality of life. Accumulating evidences endorse that olfactory sensory decline is connected with neurodegenerative disorders including schizophrenia, depression, multiple sclerosis, Huntington's, Alzheimer's and Parkinson's diseases. For several decades, neuroanatomical, volumetric, and histological approaches have been the gold standard techniques employed to characterize the olfactory bulb functionality. Diagnosis and treatment of olfactory dysfunction remain significant health care challenges to society. Novel strategies and clues that assist in the identification of biomarker and drug development for aid in the prevention and cure of neurological diseases are necessary. However, little attention has been focused specifically on the molecular composition of the olfactory bulb from the perspective of proteomics. To this end, an in-depth mapping of the olfactory bulb proteome was carried out using high resolution tandem mass spectrometry, revealing a repertoire of 7,754 proteins. A large proportion of the identified proteins were predicted to be involved in diverse biological processes including signal transduction, metabolism, transport, olfaction and protein synthesis. Pathway analysis of the identified proteins shows that, these proteins are predominantly involved in metabolic and neural processes, chromatin modeling, and synaptic vesicle transport associated with neuronal transmission. In total, our study offers valuable understandings into the molecular composition of the human olfactory bulb proteome that could possibly help neuroscience community to understand the olfactory bulb better and open avenues for intervention strategies for olfactory dysfunction in the future.

Dataset Information

Spectral unmixing: analysis of performance in the olfactory bulb in vivo.

Background

Methodology/principal findings

Conclusions/significance

Publications

Spectral unmixing: analysis of performance in the olfactory bulb in vivo.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure