Dataset Information

T-GRASP, a targeted GRASP for assessing neuronal connectivity.

ABSTRACT: BACKGROUND:Understanding how behaviors are generated by neural circuits requires knowledge of the synaptic connections between the composite neurons. Methods for mapping synaptic connections, such as electron microscopy and paired recordings, are labor intensive and alternative methods are thus desirable. NEW METHOD:Development of a targeted GFP Reconstitution Across Synaptic Partners(GRASP) method, t-GRASP, for assessing neural connectivity is described. RESULTS:Numerous different pre-synaptic and post-synaptic/dendritic proteins were tested for enhancing the specificity of GRASP signal to synaptic regions. Pairing of both targeted pre- and post-t-GRASP constructs resulted in strong preferential GRASP signal in synaptic regions in Drosophila larval sensory neurons, larval neuromuscular junctions, and adult photoreceptor neurons with minimal false-positive signal. COMPARISON WITH EXISTING METHODS:Activity-independent t-GRASP exhibits an enhancement of GRASP signal specificity for synaptic contact sites as compared to existing Drosophila GRASP methods. Fly strains were developed for expression of both pre- and post-t-GRASP with each of the three Drosophila binary transcription systems, thus enabling GRASP assays to be performed between any two driver pairs of any transcription system in either direction, an option not available for existing Drosophila GRASP methods. CONCLUSIONS:t-GRASP is a novel targeted GRASP method for assessing synaptic connectivity between Drosophila neurons. Its flexibility of use with all three Drosophila binary transcription systems significantly expands the potential use of GRASP in Drosophila.

SUBMITTER: Shearin HK

PROVIDER: S-EPMC6689385 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

t-GRASP, a targeted GRASP for assessing neuronal connectivity.

Shearin Harold K HK Quinn Casey D CD Mackin Robert D RD Macdonald Ian S IS Stowers R Steven RS

Journal of neuroscience methods 20180521

<h4>Background</h4>Understanding how behaviors are generated by neural circuits requires knowledge of the synaptic connections between the composite neurons. Methods for mapping synaptic connections, such as electron microscopy and paired recordings, are labor intensive and alternative methods are thus desirable.<h4>New method</h4>Development of a targeted GFP Reconstitution Across Synaptic Partners(GRASP) method, t-GRASP, for assessing neural connectivity is described.<h4>Results</h4>Numerous d ...[more]

PMID: 29792886

Similar Datasets

Project description:Coordinated reach-to-grasp movements require precise spatiotemporal synchrony between proximal forelimb muscles (shoulder, elbow) that transport the hand toward a target during reach, and distal muscles (wrist, digit) that simultaneously preshape and orient the hand for grasp. The precise mechanisms through which the redundant neuromuscular circuitry coordinates reach with grasp, however, remain unclear. Recently, Geed and Van Kan (2016) demonstrated, using exploratory factor analysis (EFA), that limited numbers of global, template-like transport/preshape- and grasp-related muscle components underlie the complexity and variability of intramuscular electromyograms (EMGs) of up to 21 distal and proximal muscles recorded while monkeys performed reach-to-grasp tasks. Importantly, transport/preshape- and grasp-related muscle components showed invariant spatiotemporal coupling, which provides a potential mechanism for coordinating forelimb muscles during reach-to-grasp movements. In the present study, we tested whether ensemble discharges of forelimb neurons in the cerebellar nucleus interpositus (NI) and its target, the magnocellular red nucleus (RNm), a source of rubrospinal fibers, function as neuronal correlates of the transport/preshape- and grasp-related muscle components we identified. EFA applied to single-unit discharges of populations of NI and RNm neurons recorded while the same monkeys that were used previously performed the same reach-to-grasp tasks, revealed neuronal components in the ensemble discharges of both NI and RNm neuronal populations with characteristics broadly similar to muscle components. Subsets of NI and RNm neuronal components were strongly and significantly crosscorrelated with subsets of muscle components, suggesting that similar functional units of reach-to-grasp behavior are expressed by NI and RNm neuronal populations and forelimb muscles. Importantly, like transport/preshape- and grasp-related muscle components, their NI and RNm neuronal correlates showed invariant spatiotemporal coupling. Clinical and lesion studies have reported disruption of coupling between reach and grasp following cerebellar damage; the present results expand on those studies by identifying a neuronal mechanism that may underlie cerebellar contributions to spatiotemporal coordination of distal and proximal limb muscles during reaching to grasp. We conclude that finding similar functional units of behavior expressed at multiple levels of information processing along interposito-rubrospinal pathways and forelimb muscles supports the hypothesis that functionally related populations of NI and RNm neurons act synergistically in the control of complex coordinated motor behaviors.

Dataset Information

T-GRASP, a targeted GRASP for assessing neuronal connectivity.

Publications

t-GRASP, a targeted GRASP for assessing neuronal connectivity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets