@article {47161, title = {Imaging fictive locomotor patterns in larval Drosophila.}, journal = {Journal of Neurophysiology}, volume = {114}, year = {2015}, month = {2015 Nov 06}, pages = {2564-77}, abstract = {

We have established a preparation in larval Drosophila to monitor fictive locomotion simultaneously across abdominal and thoracic segments of the isolated CNS with genetically encoded Ca(2+) indicators. The Ca(2+) signals closely followed spiking activity measured electrophysiologically in nerve roots. Three motor patterns are analyzed. Two comprise waves of Ca(2+) signals that progress along the longitudinal body axis in a posterior-to-anterior or anterior-to-posterior direction. These waves had statistically indistinguishable intersegmental phase delays compared with segmental contractions during forward and backward crawling behavior, despite being \~{}10 times slower. During these waves, motor neurons of the dorsal longitudinal and transverse muscles were active in the same order as the muscle groups are recruited during crawling behavior. A third fictive motor pattern exhibits a left-right asymmetry across segments and bears similarities with turning behavior in intact larvae, occurring equally frequently and involving asymmetry in the same segments. Ablation of the segments in which forward and backward waves of Ca(2+) signals were normally initiated did not eliminate production of Ca(2+) waves. When the brain and subesophageal ganglion (SOG) were removed, the remaining ganglia retained the ability to produce both forward and backward waves of motor activity, although the speed and frequency of waves changed. Bilateral asymmetry of activity was reduced when the brain was removed and abolished when the SOG was removed. This work paves the way to studying the neural and genetic underpinnings of segmentally coordinated motor pattern generation in Drosophila with imaging techniques.

}, issn = {1522-1598}, doi = {10.1152/jn.00731.2015}, author = {Pulver, Stefan R and Bayley, Timothy G and Taylor, Adam L and Berni, Jimena and Bate, Michael and Hedwig, Berthold} } @article {2377, title = {Positional cues in the Drosophila nerve cord: semaphorins pattern the dorso-ventral axis.}, journal = {PLoS Biology}, volume = {7}, year = {2009}, month = {2009 Jun 16}, pages = {e1000135}, abstract = {

During the development of neural circuitry, neurons of different kinds establish specific synaptic connections by selecting appropriate targets from large numbers of alternatives. The range of alternative targets is reduced by well organised patterns of growth, termination, and branching that deliver the terminals of appropriate pre- and postsynaptic partners to restricted volumes of the developing nervous system. We use the axons of embryonic Drosophila sensory neurons as a model system in which to study the way in which growing neurons are guided to terminate in specific volumes of the developing nervous system. The mediolateral positions of sensory arbors are controlled by the response of Robo receptors to a Slit gradient. Here we make a genetic analysis of factors regulating position in the dorso-ventral axis. We find that dorso-ventral layers of neuropile contain different levels and combinations of Semaphorins. We demonstrate the existence of a central to dorsal and central to ventral gradient of Sema 2a, perpendicular to the Slit gradient. We show that a combination of Plexin A (Plex A) and Plexin B (Plex B) receptors specifies the ventral projection of sensory neurons by responding to high concentrations of Semaphorin 1a (Sema 1a) and Semaphorin 2a (Sema 2a). Together our findings support the idea that axons are delivered to particular regions of the neuropile by their responses to systems of positional cues in each dimension.

}, keywords = {Animals, Axons, Cell Surface, Drosophila, Drosophila Proteins, Nerve Net, Nerve Tissue Proteins, Neurogenesis, Neuropil, Receptors, Semaphorins, Sensory Receptor Cells, Synapses}, issn = {1545-7885}, doi = {10.1371/journal.pbio.1000135}, author = {Zlatic, Marta and Li, Feng and Strigini, Maura and Grueber, Wesley and Bate, Michael} } @article {2380, title = {Genetic specification of axonal arbors: atonal regulates robo3 to position terminal branches in the Drosophila nervous system.}, journal = {Neuron}, volume = {37}, year = {2003}, month = {2003 Jan 9}, pages = {41-51}, abstract = {

Drosophila sensory neurons form distinctive terminal branch patterns in the developing neuropile of the embryonic central nervous system. In this paper we make a genetic analysis of factors regulating arbor position. We show that mediolateral position is determined in a binary fashion by expression (chordotonal neurons) or nonexpression (multidendritic neurons) of the Robo3 receptor for the midline repellent Slit. Robo3 expression is one of a suite of chordotonal neuron properties that depend on expression of the proneural gene atonal. Different features of terminal branches are separately regulated: an arbor can be shifted mediolaterally without affecting its dorsoventral location, and the distinctive remodeling of one arbor continues as normal despite this arbor shifting to an abnormal position in the neuropile.

}, keywords = {Afferent, Animals, Axons, Basic Helix-Loop-Helix Transcription Factors, Cell Communication, Cell Differentiation, Developmental, DNA-Binding Proteins, Drosophila melanogaster, Drosophila Proteins, Embryo, Female, Functional Laterality, Gene Expression Regulation, Growth Cones, Immunologic, Larva, Male, Membrane Proteins, Mutation, Nerve Tissue Proteins, Nervous System, Nervous System Malformations, Neuronal Plasticity, Neurons, Nonmammalian, Presynaptic Terminals, Receptors}, issn = {0896-6273}, author = {Zlatic, Marta and Landgraf, Matthias and Bate, Michael} }