251
|
Abstract
Hierarchically organized brains communicate through feedforward (FF) and feedback (FB) pathways. In mammals, FF and FB are mediated by higher and lower frequencies during wakefulness. FB is preferentially impaired by general anesthetics in multiple mammalian species. This suggests FB serves critical functions in waking brains. The brain of Drosophila melanogaster (fruit fly) is also hierarchically organized, but the presence of FB in these brains is not established. Here, we studied FB in the fly brain, by simultaneously recording local field potentials (LFPs) from low-order peripheral structures and higher-order central structures. We analyzed the data using Granger causality (GC), the first application of this analysis technique to recordings from the insect brain. Our analysis revealed that low frequencies (0.1–5 Hz) mediated FB from the center to the periphery, while higher frequencies (10–45 Hz) mediated FF in the opposite direction. Further, isoflurane anesthesia preferentially reduced FB. Our results imply that the spectral characteristics of FF and FB may be a signature of hierarchically organized brains that is conserved from insects to mammals. We speculate that general anesthetics may induce unresponsiveness across species by targeting the mechanisms that support FB.
Collapse
|
252
|
Selcho M, Mühlbauer B, Hensgen R, Shiga S, Wegener C, Yasuyama K. Anatomical characterization of PDF-tri neurons and peptidergic neurons associated with eclosion behavior in Drosophila. J Comp Neurol 2018; 526:1307-1328. [DOI: 10.1002/cne.24408] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Mareike Selcho
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter; University of Würzburg; Würzburg D-97074 Germany
| | - Barbara Mühlbauer
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter; University of Würzburg; Würzburg D-97074 Germany
| | - Ronja Hensgen
- Animal Physiology, Department of Biology; Philipps-University Marburg; Marburg D-35032 Germany
| | - Sakiko Shiga
- Department of Biology and Geosciences, Graduate School of Science; Osaka City University; Osaka 558-8585 Japan
| | - Christian Wegener
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter; University of Würzburg; Würzburg D-97074 Germany
| | - Kouji Yasuyama
- Department of Natural Sciences; Kawasaki Medical School; Kurashiki 701-0192 Japan
| |
Collapse
|
253
|
Identification of a Single Pair of Interneurons for Bitter Taste Processing in the Drosophila Brain. Curr Biol 2018; 28:847-858.e3. [PMID: 29502953 DOI: 10.1016/j.cub.2018.01.084] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/20/2017] [Accepted: 01/30/2018] [Indexed: 11/23/2022]
Abstract
Drosophila has become an excellent model system for investigating the organization and function of the gustatory system due to the relatively simple neuroanatomical organization of its brain and the availability of powerful genetic and transgenic technology. Thus, at the molecular and cellular levels, a great deal of insight into the peripheral detection and coding of gustatory information has already been attained. In contrast, much less is known about the central neural circuits that process this information and induce behaviorally appropriate motor output. Here, we combine functional behavioral tests with targeted transgene expression through specific driver lines to identify a single bilaterally homologous pair of bitter-sensitive interneurons that are located in the subesophageal zone of the brain. Anatomical and functional data indicate that these interneurons receive specific synaptic input from bitter-sensitive gustatory receptor neurons. Targeted transgenic activation and inactivation experiments show that these bitter-sensitive interneurons can largely suppress the proboscis extension reflex to appetitive stimuli, such as sugar and water. These functional experiments, together with calcium-imaging studies and calcium-modulated photoactivatable ratiometric integrator (CaMPARI) labeling, indicate that these first-order local interneurons play an important role in the inhibition of the proboscis extension reflex that occurs in response to bitter tastants. Taken together, our studies present a cellular identification and functional characterization of a key gustatory interneuron in the bitter-sensitive gustatory circuitry of the adult fly.
Collapse
|
254
|
Diesner M, Gallot A, Binz H, Gaertner C, Vitecek S, Kahnt J, Schachtner J, Jacquin-Joly E, Gadenne C. Mating-Induced Differential Peptidomics of Neuropeptides and Protein Hormones in Agrotis ipsilon Moths. J Proteome Res 2018; 17:1397-1414. [PMID: 29466015 DOI: 10.1021/acs.jproteome.7b00779] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In many insects, mating induces drastic changes in male and female responses to sex pheromones or host-plant odors. In the male moth Agrotis ipsilon, mating induces a transient inhibition of behavioral and neuronal responses to the female sex pheromone. As neuropeptides and peptide hormones regulate most behavioral processes, we hypothesize that they could be involved in this mating-dependent olfactory plasticity. Here we used next-generation RNA sequencing and a combination of liquid chromatography, matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, and direct tissue profiling to analyze the transcriptome and peptidome of different brain compartments in virgin and mated males and females of A. ipsilon. We identified 37 transcripts encoding putative neuropeptide precursors and 54 putative bioactive neuropeptides from 23 neuropeptide precursors (70 sequences in total, 25 neuropeptide precursors) in different areas of the central nervous system including the antennal lobes, the gnathal ganglion, and the corpora cardiaca-corpora allata complex. Comparisons between virgin and mated males and females revealed tissue-specific differences in peptide composition between sexes and according to physiological state. Mated males showed postmating differences in neuropeptide occurrence, which could participate in the mating-induced olfactory plasticity.
Collapse
Affiliation(s)
- Max Diesner
- Department of Biology - Animal Physiology , Philipps University Marburg , D-35032 Marburg , Germany
| | - Aurore Gallot
- Institut d'Ecologie et des Sciences de l'Environnement de Paris (UMR iEES-Paris) , INRA , Route de Saint-Cyr , 78026 Versailles Cedex , France
| | - Hellena Binz
- Institute of Zoology , University of Mainz , Johann-Joachim-Becher-Weg 6 , 55128 Mainz , Germany
| | - Cyril Gaertner
- Institut d'Ecologie et des Sciences de l'Environnement de Paris (UMR iEES-Paris) , INRA , Route de Saint-Cyr , 78026 Versailles Cedex , France
| | - Simon Vitecek
- Institut d'Ecologie et des Sciences de l'Environnement de Paris (UMR iEES-Paris) , INRA , Route de Saint-Cyr , 78026 Versailles Cedex , France
| | - Jörg Kahnt
- Max-Planck-Institute für terrestrische Mikrobiologie, Marburg , Germany
| | - Joachim Schachtner
- Department of Biology - Animal Physiology , Philipps University Marburg , D-35032 Marburg , Germany
| | - Emmanuelle Jacquin-Joly
- Institut d'Ecologie et des Sciences de l'Environnement de Paris (UMR iEES-Paris) , INRA , Route de Saint-Cyr , 78026 Versailles Cedex , France
| | - Christophe Gadenne
- Institut de Génétique, Environnement et Protection des Plantes (UMR IGEPP) , INRA , Agrocampus Ouest, rue Le Nôtre , 49054 Angers cedex 01 , France
| |
Collapse
|
255
|
Elucidating the Neuronal Architecture of Olfactory Glomeruli in the Drosophila Antennal Lobe. Cell Rep 2018; 16:3401-3413. [PMID: 27653699 DOI: 10.1016/j.celrep.2016.08.063] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 07/15/2016] [Accepted: 08/18/2016] [Indexed: 11/21/2022] Open
Abstract
Olfactory glomeruli are morphologically conserved spherical compartments of the olfactory system, distinguishable solely by their chemosensory repertoire, anatomical position, and volume. Little is known, however, about their numerical neuronal composition. We therefore characterized their neuronal architecture and correlated these anatomical features with their functional properties in Drosophila melanogaster. We quantitatively mapped all olfactory sensory neurons (OSNs) innervating each glomerulus, including sexually dimorphic distributions. Our data reveal the impact of OSN number on glomerular dimensions and demonstrate yet unknown sex-specific differences in several glomeruli. Moreover, we quantified uniglomerular projection neurons for each glomerulus, which unraveled a glomerulus-specific numerical innervation. Correlation between morphological features and functional specificity showed that glomeruli innervated by narrowly tuned OSNs seem to possess a larger number of projection neurons and are involved in less lateral processing than glomeruli targeted by broadly tuned OSNs. Our study demonstrates that the neuronal architecture of each glomerulus encoding crucial odors is unique.
Collapse
|
256
|
Spatial Receptive Fields for Odor Localization. Curr Biol 2018; 28:600-608.e3. [PMID: 29429617 DOI: 10.1016/j.cub.2017.12.055] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/14/2017] [Accepted: 12/28/2017] [Indexed: 11/20/2022]
Abstract
Animals rely on olfaction to navigate through complex olfactory landscapes, but the mechanisms that allow an animal to encode the spatial structure of an odorous environment remain unclear. To acquire information about the spatial distribution of an odorant, animals may rely on bilateral olfactory organs and compare side differences of odor intensity and timing [1-6] or may perform spatial and temporal signal integration of subsequent samplings [7]. The American cockroach can efficiently locate a source of sex pheromone even after the removal of one antenna, suggesting that bilateral comparison is not a prerequisite for odor localization in this species [8, 9]. Cognate olfactory sensory neurons (OSNs) originating from different locations on the flagellum, but bearing the same olfactory receptor, converge onto the same glomerulus within the antennal lobe, which is thought to result in a loss of spatial information. Here, we identified 12 types of pheromone-responsive projection neurons (PNs), each with spatially tuned receptive field. The combination of (1) the antennotopic organization of OSNs terminals and (2) the stereotyped compartmentalization of PNs' dendritic arborization within the macroglomerulus (MG), allows encoding the spatial position of the pheromone. Furthermore, each PN type innervates a different compartment of the mushroom body, providing the means for encoding spatial olfactory information along the olfactory circuit. Finally, MG PNs exhibit both excitatory and inhibitory spatial receptive fields and modulate their responses based on changes in stimulus geometry. In conclusion, we propose a mechanism for encoding information on the spatial distribution of a pheromone, expanding both our understanding of odor coding and of the strategies insects adopt to localize a sexual mate.
Collapse
|
257
|
Rickert C, Lüer K, Vef O, Technau GM. Progressive derivation of serially homologous neuroblast lineages in the gnathal CNS of Drosophila. PLoS One 2018; 13:e0191453. [PMID: 29415052 PMCID: PMC5802887 DOI: 10.1371/journal.pone.0191453] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/04/2018] [Indexed: 11/18/2022] Open
Abstract
Along the anterior-posterior axis the central nervous system is subdivided into segmental units (neuromeres) the composition of which is adapted to their region-specific functional requirements. In Drosophila melanogaster each neuromere is formed by a specific set of identified neural stem cells (neuroblasts, NBs). In the thoracic and anterior abdominal region of the embryonic ventral nerve cord segmental sets of NBs resemble the ground state (2nd thoracic segment, which does not require input of homeotic genes), and serial (segmental) homologs generate similar types of lineages. The three gnathal head segments form a transitional zone between the brain and the ventral nerve cord. It has been shown recently that although all NBs of this zone are serial homologs of NBs in more posterior segments, they progressively differ from the ground state in anterior direction (labial > maxillary > mandibular segment) with regard to numbers and expression profiles. To study the consequences of their derived characters we traced the embryonic lineages of gnathal NBs using the Flybow and DiI-labelling techniques. For a number of clonal types serial homology is rather clearly reflected by their morphology (location and projection patterns) and cell specific markers, despite of reproducible segment-specific differences. However, many lineages, particularly in the mandibular segment, show a degree of derivation that impedes their assignment to ground state serial homologs. These findings demonstrate that differences in gene expression profiles of gnathal NBs go along with anteriorly directed progressive derivation in the composition of their lineages. Furthermore, lineage sizes decrease from labial to mandibular segments, which in concert with decreasing NB-numbers lead to reduced volumes of gnathal neuromeres, most significantly in the mandibular segment.
Collapse
Affiliation(s)
- Christof Rickert
- Institute of Developmental Biology and Neurobiology, University of Mainz, J.-J.-Becherweg 32,Mainz, Germany
- * E-mail: (CR); (GMT)
| | - Karin Lüer
- Institute of Developmental Biology and Neurobiology, University of Mainz, J.-J.-Becherweg 32,Mainz, Germany
| | - Olaf Vef
- Institute of Developmental Biology and Neurobiology, University of Mainz, J.-J.-Becherweg 32,Mainz, Germany
| | - Gerhard M. Technau
- Institute of Developmental Biology and Neurobiology, University of Mainz, J.-J.-Becherweg 32,Mainz, Germany
- * E-mail: (CR); (GMT)
| |
Collapse
|
258
|
Kropf J, Rössler W. In-situ recording of ionic currents in projection neurons and Kenyon cells in the olfactory pathway of the honeybee. PLoS One 2018; 13:e0191425. [PMID: 29351552 PMCID: PMC5774781 DOI: 10.1371/journal.pone.0191425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/04/2018] [Indexed: 11/18/2022] Open
Abstract
The honeybee olfactory pathway comprises an intriguing pattern of convergence and divergence: ~60.000 olfactory sensory neurons (OSN) convey olfactory information on ~900 projection neurons (PN) in the antennal lobe (AL). To transmit this information reliably, PNs employ relatively high spiking frequencies with complex patterns. PNs project via a dual olfactory pathway to the mushroom bodies (MB). This pathway comprises the medial (m-ALT) and the lateral antennal lobe tract (l-ALT). PNs from both tracts transmit information from a wide range of similar odors, but with distinct differences in coding properties. In the MBs, PNs form synapses with many Kenyon cells (KC) that encode odors in a spatially and temporally sparse way. The transformation from complex information coding to sparse coding is a well-known phenomenon in insect olfactory coding. Intrinsic neuronal properties as well as GABAergic inhibition are thought to contribute to this change in odor representation. In the present study, we identified intrinsic neuronal properties promoting coding differences between PNs and KCs using in-situ patch-clamp recordings in the intact brain. We found very prominent K+ currents in KCs clearly differing from the PN currents. This suggests that odor coding differences between PNs and KCs may be caused by differences in their specific ion channel properties. Comparison of ionic currents of m- and l-ALT PNs did not reveal any differences at a qualitative level.
Collapse
Affiliation(s)
- Jan Kropf
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
| |
Collapse
|
259
|
Sears JC, Broadie K. Fragile X Mental Retardation Protein Regulates Activity-Dependent Membrane Trafficking and Trans-Synaptic Signaling Mediating Synaptic Remodeling. Front Mol Neurosci 2018; 10:440. [PMID: 29375303 PMCID: PMC5770364 DOI: 10.3389/fnmol.2017.00440] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/18/2017] [Indexed: 12/31/2022] Open
Abstract
Fragile X syndrome (FXS) is the leading monogenic cause of autism and intellectual disability. The disease arises through loss of fragile X mental retardation protein (FMRP), which normally exhibits peak expression levels in early-use critical periods, and is required for activity-dependent synaptic remodeling during this transient developmental window. FMRP canonically binds mRNA to repress protein translation, with targets that regulate cytoskeleton dynamics, membrane trafficking, and trans-synaptic signaling. We focus here on recent advances emerging in these three areas from the Drosophila disease model. In the well-characterized central brain mushroom body (MB) olfactory learning/memory circuit, FMRP is required for activity-dependent synaptic remodeling of projection neurons innervating the MB calyx, with function tightly restricted to an early-use critical period. FMRP loss is phenocopied by conditional removal of FMRP only during this critical period, and rescued by FMRP conditional expression only during this critical period. Consistent with FXS hyperexcitation, FMRP loss defects are phenocopied by heightened sensory experience and targeted optogenetic hyperexcitation during this critical period. FMRP binds mRNA encoding Drosophila ESCRTIII core component Shrub (human CHMP4 homolog) to restrict Shrub translation in an activity-dependent mechanism only during this same critical period. Shrub mediates endosomal membrane trafficking, and perturbing Shrub expression is known to interfere with neuronal process pruning. Consistently, FMRP loss and Shrub overexpression targeted to projection neurons similarly causes endosomal membrane trafficking defects within synaptic boutons, and genetic reduction of Shrub strikingly rescues Drosophila FXS model defects. In parallel work on the well-characterized giant fiber (GF) circuit, FMRP limits iontophoretic dye loading into central interneurons, demonstrating an FMRP role controlling core neuronal properties through the activity-dependent repression of translation. In the well-characterized Drosophila neuromuscular junction (NMJ) model, developmental synaptogenesis and activity-dependent synaptic remodeling both require extracellular matrix metalloproteinase (MMP) enzymes interacting with the heparan sulfate proteoglycan (HSPG) glypican dally-like protein (Dlp) to restrict trans-synaptic Wnt signaling, with FXS synaptogenic defects alleviated by both MMP and HSPG reduction. This new mechanistic axis spanning from activity to FMRP to HSPG-dependent MMP regulation modulates activity-dependent synaptogenesis. We discuss future directions for these mechanisms, and intersecting research priorities for FMRP in glial and signaling interactions.
Collapse
Affiliation(s)
- James C. Sears
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
- Vanderbilt Kennedy Center for Research on Human Development, Nashville, TN, United States
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| |
Collapse
|
260
|
Image processing for precise three-dimensional registration and stitching of thick high-resolution laser-scanning microscopy image stacks. Comput Biol Med 2018; 92:22-41. [DOI: 10.1016/j.compbiomed.2017.10.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/03/2017] [Accepted: 10/23/2017] [Indexed: 12/13/2022]
|
261
|
Hartenstein V, Omoto JJ, Ngo KT, Wong D, Kuert PA, Reichert H, Lovick JK, Younossi-Hartenstein A. Structure and development of the subesophageal zone of the Drosophila brain. I. Segmental architecture, compartmentalization, and lineage anatomy. J Comp Neurol 2018; 526:6-32. [PMID: 28730682 PMCID: PMC5963519 DOI: 10.1002/cne.24287] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/13/2017] [Accepted: 07/17/2017] [Indexed: 02/03/2023]
Abstract
The subesophageal zone (SEZ) of the Drosophila brain houses the circuitry underlying feeding behavior and is involved in many other aspects of sensory processing and locomotor control. Formed by the merging of four neuromeres, the internal architecture of the SEZ can be best understood by identifying segmentally reiterated landmarks emerging in the embryo and larva, and following the gradual changes by which these landmarks become integrated into the mature SEZ during metamorphosis. In previous works, the system of longitudinal fibers (connectives) and transverse axons (commissures) has been used as a scaffold that provides internal landmarks for the neuromeres of the larval ventral nerve cord. We have extended the analysis of this scaffold to the SEZ and, in addition, reconstructed the tracts formed by lineages and nerves in relationship to the connectives and commissures. As a result, we establish reliable criteria that define boundaries between the four neuromeres (tritocerebrum, mandibular neuromere, maxillary neuromere, labial neuromere) of the SEZ at all stages of development. Fascicles and lineage tracts also demarcate seven columnar neuropil domains (ventromedial, ventro-lateral, centromedial, central, centrolateral, dorsomedial, dorsolateral) identifiable throughout development. These anatomical subdivisions, presented in the form of an atlas including confocal sections and 3D digital models for the larval, pupal and adult stage, allowed us to describe the morphogenetic changes shaping the adult SEZ. Finally, we mapped MARCM-labeled clones of all secondary lineages of the SEZ to the newly established neuropil subdivisions. Our work will facilitate future studies of function and comparative anatomy of the SEZ.
Collapse
Affiliation(s)
- Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jaison J. Omoto
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Kathy T. Ngo
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Darren Wong
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | | | | | - Jennifer K. Lovick
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Amelia Younossi-Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| |
Collapse
|
262
|
Kendroud S, Bohra AA, Kuert PA, Nguyen B, Guillermin O, Sprecher SG, Reichert H, VijayRaghavan K, Hartenstein V. Structure and development of the subesophageal zone of the Drosophila brain. II. Sensory compartments. J Comp Neurol 2018; 526:33-58. [PMID: 28875566 PMCID: PMC5971197 DOI: 10.1002/cne.24316] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/15/2017] [Accepted: 08/15/2017] [Indexed: 12/29/2022]
Abstract
The subesophageal zone (SEZ) of the Drosophila brain processes mechanosensory and gustatory sensory input from sensilla located on the head, mouth cavity and trunk. Motor output from the SEZ directly controls the movements involved in feeding behavior. In an accompanying paper (Hartenstein et al., ), we analyzed the systems of fiber tracts and secondary lineages to establish reliable criteria for defining boundaries between the four neuromeres of the SEZ, as well as discrete longitudinal neuropil domains within each SEZ neuromere. Here we use this anatomical framework to systematically map the sensory projections entering the SEZ throughout development. Our findings show continuity between larval and adult sensory neuropils. Gustatory axons from internal and external taste sensilla of the larva and adult form two closely related sensory projections, (a) the anterior central sensory center located deep in the ventromedial neuropil of the tritocerebrum and mandibular neuromere, and (b) the anterior ventral sensory center (AVSC), occupying a superficial layer within the ventromedial tritocerebrum. Additional, presumed mechanosensory terminal axons entering via the labial nerve define the ventromedial sensory center (VMSC) in the maxilla and labium. Mechanosensory afferents of the massive array of chordotonal organs (Johnston's organ) of the adult antenna project into the centrolateral neuropil column of the anterior SEZ, creating the antenno-mechanosensory and motor center (AMMC). Dendritic projections of dye back-filled motor neurons extend throughout a ventral layer of the SEZ, overlapping widely with the AVSC and VMSC. Our findings elucidate fundamental structural aspects of the developing sensory systems in Drosophila.
Collapse
Affiliation(s)
- Sarah Kendroud
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ali Asgar Bohra
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, India
| | | | - Bao Nguyen
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Oriane Guillermin
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Simon G. Sprecher
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | | | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| |
Collapse
|
263
|
Abstract
The brain is a network of neurons, one that generates behaviour, and knowing the former is crucial to understanding the latter. Identifying the exact network of synaptic connections, or connectome, of the fly's central nervous system is now a major objective in Drosophila neurobiology, one that has been initiated in several laboratories, especially the Janelia Research Campus of the Howard Hughes Medical Institute. Progress is most advanced in the optic neuropiles of the visual system. The effort to derive a connectome from these and other neuropile regions is proceeding by various methods of electron microscopy, especially focused-ion beam milling scanning electron microscopy, and relies upon - but is to be carefully distinguished from - published light microscopic methods that reveal the projections of genetically labelled cell types. The latter reveal those neurons that come into close proximity and are therefore candidate synaptic partners. Synaptic partnerships are not in fact reliably revealed by such candidate pairs, anatomical connections often revealing unexpected pathways. Synaptic partnerships identified from ultrastructural features provide a strong heuristic basis to interpret not only functional interactions between identified neurons, but also a powerful means to predict such interactions, and suggest functional pathways not readily predicted from existing experimental evidence. The analysis of circuit function may proceed cell by cell, by examining the behavioural outcome of either interrupting or restoring function to any one element in an anatomically defined circuit, but can be foiled by degeneracy in pathway elements. Circuit information can also be used to identify and analyse circuit motifs, and their role in higher-order network properties. These attempts in Drosophila anticipate parallel attempts in other systems, notably the inner plexiform layer of the vertebrate retina, and augment the one complete connectome already available to us, that available for 30 years in the nematode Caenorhabditis elegans.
Collapse
Affiliation(s)
- Ian A Meinertzhagen
- a Department of Psychology and Neuroscience, Life Sciences Centre , Dalhousie University , Halifax , Canada ;,b Janelia Research Campus of Howard Hughes Medical Institute , Ashburn , VA , USA
| |
Collapse
|
264
|
Huang TH, Niesman P, Arasu D, Lee D, De La Cruz AL, Callejas A, Hong EJ, Lois C. Tracing neuronal circuits in transgenic animals by transneuronal control of transcription ( TRACT). eLife 2017; 6:32027. [PMID: 29231171 PMCID: PMC5777821 DOI: 10.7554/elife.32027] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/02/2017] [Indexed: 12/20/2022] Open
Abstract
Understanding the computations that take place in brain circuits requires identifying how neurons in those circuits are connected to one another. We describe a technique called TRACT (TRAnsneuronal Control of Transcription) based on ligand-induced intramembrane proteolysis to reveal monosynaptic connections arising from genetically labeled neurons of interest. In this strategy, neurons expressing an artificial ligand (‘donor’ neurons) bind to and activate a genetically-engineered artificial receptor on their synaptic partners (‘receiver’ neurons). Upon ligand-receptor binding at synapses the receptor is cleaved in its transmembrane domain and releases a protein fragment that activates transcription in the synaptic partners. Using TRACT in Drosophila we have confirmed the connectivity between olfactory receptor neurons and their postsynaptic targets, and have discovered potential new connections between neurons in the circadian circuit. Our results demonstrate that the TRACT method can be used to investigate the connectivity of neuronal circuits in the brain. One of the main obstacles to understanding how the brain works is that we know relatively little about how its nerve cells or neurons are connected to one another. These connections make up the brain’s wiring diagram. Current methods for revealing this wiring all have limitations. The most popular method – serial electron microscopy – can reveal the connections in a small region of the brain in great detail, but it cannot show connections between neurons that are far apart. Huang et al. have now created a genetic system for visualizing these connections. For neurons to communicate, one neuron must produce a signal called a ligand. This ligand can then bind to and activate its partner neuron. Huang et al. modified the DNA of neurons so that every time those cells produced a specific ligand, they also produced a red fluorescent protein. Similar modifications ensured that every time the ligand activated a partner neuron, the activated neuron produced a green fluorescent protein. Viewing the red and green neurons under a microscope enabled Huang et al. to see which cells were communicating with which others. While these experiments took place in fruit flies, the same approach should also work in other laboratory animals, including fish, mice and rats. Once we know the wiring diagram of the brain, the next step is to investigate the role of the various connections. To understand how a computer works, for example, we might change the connections between its circuit components and look at how this affects the computer’s output. With this new method, we can change how neurons communicate with one another in the brain, and then look at the effects on behavior. This should provide insights into the workings of the human brain, and clues to what goes wrong in disorders like schizophrenia and autism.
Collapse
Affiliation(s)
- Ting-Hao Huang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Peter Niesman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Deepshika Arasu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Donghyung Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Aubrie L De La Cruz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Antuca Callejas
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States.,Department of Cell Biology, School of Science, University of Extremadura, Badajoz, Spain
| | - Elizabeth J Hong
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Carlos Lois
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| |
Collapse
|
265
|
Crustacean olfactory systems: A comparative review and a crustacean perspective on olfaction in insects. Prog Neurobiol 2017; 161:23-60. [PMID: 29197652 DOI: 10.1016/j.pneurobio.2017.11.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 11/10/2017] [Accepted: 11/28/2017] [Indexed: 12/20/2022]
Abstract
Malacostracan crustaceans display a large diversity of sizes, morphs and life styles. However, only a few representatives of decapod taxa have served as models for analyzing crustacean olfaction, such as crayfish and spiny lobsters. Crustaceans bear multiple parallel chemosensory pathways represented by different populations of unimodal chemosensory and bimodal chemo- and mechanosensory sensilla on the mouthparts, the walking limbs and primarily on their two pairs of antennae. Here, we focus on the olfactory pathway associated with the unimodal chemosensory sensilla on the first antennal pair, the aesthetascs. We explore the diverse arrangement of these sensilla across malacostracan taxa and point out evolutionary transformations which occurred in the central olfactory pathway. We discuss the evolution of chemoreceptor proteins, comparative aspects of active chemoreception and the temporal resolution of crustacean olfactory system. Viewing the evolution of crustacean brains in light of energetic constraints can help us understand their functional morphology and suggests that in various crustacean lineages, the brains were simplified convergently because of metabolic limitations. Comparing the wiring of afferents, interneurons and output neurons within the olfactory glomeruli suggests a deep homology of insect and crustacean olfactory systems. However, both taxa followed distinct lineages during the evolutionary elaboration of their olfactory systems. A comparison with insects suggests their olfactory systems ö especially that of the vinegar fly ö to be superb examples for "economy of design". Such a comparison also inspires new thoughts about olfactory coding and the functioning of malacostracan olfactory systems in general.
Collapse
|
266
|
Grob R, Fleischmann PN, Grübel K, Wehner R, Rössler W. The Role of Celestial Compass Information in Cataglyphis Ants during Learning Walks and for Neuroplasticity in the Central Complex and Mushroom Bodies. Front Behav Neurosci 2017; 11:226. [PMID: 29184487 PMCID: PMC5694495 DOI: 10.3389/fnbeh.2017.00226] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/30/2017] [Indexed: 11/27/2022] Open
Abstract
Central place foragers are faced with the challenge to learn the position of their nest entrance in its surroundings, in order to find their way back home every time they go out to search for food. To acquire navigational information at the beginning of their foraging career, Cataglyphis noda performs learning walks during the transition from interior worker to forager. These small loops around the nest entrance are repeatedly interrupted by strikingly accurate back turns during which the ants stop and precisely gaze back to the nest entrance—presumably to learn the landmark panorama of the nest surroundings. However, as at this point the complete navigational toolkit is not yet available, the ants are in need of a reference system for the compass component of the path integrator to align their nest entrance-directed gazes. In order to find this directional reference system, we systematically manipulated the skylight information received by ants during learning walks in their natural habitat, as it has been previously suggested that the celestial compass, as part of the path integrator, might provide such a reference system. High-speed video analyses of distinct learning walk elements revealed that even exclusion from the skylight polarization pattern, UV-light spectrum and the position of the sun did not alter the accuracy of the look back to the nest behavior. We therefore conclude that C. noda uses a different reference system to initially align their gaze directions. However, a comparison of neuroanatomical changes in the central complex and the mushroom bodies before and after learning walks revealed that exposure to UV light together with a naturally changing polarization pattern was essential to induce neuroplasticity in these high-order sensory integration centers of the ant brain. This suggests a crucial role of celestial information, in particular a changing polarization pattern, in initially calibrating the celestial compass system.
Collapse
Affiliation(s)
- Robin Grob
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
| | - Pauline N Fleischmann
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
| | - Kornelia Grübel
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
| | - Rüdiger Wehner
- Brain Research Institute, University of Zürich, Zürich, Switzerland
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
| |
Collapse
|
267
|
Transsynaptic Mapping of Second-Order Taste Neurons in Flies by trans-Tango. Neuron 2017; 96:783-795.e4. [PMID: 29107518 DOI: 10.1016/j.neuron.2017.10.011] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 06/30/2017] [Accepted: 10/05/2017] [Indexed: 12/27/2022]
Abstract
Mapping neural circuits across defined synapses is essential for understanding brain function. Here we describe trans-Tango, a technique for anterograde transsynaptic circuit tracing and manipulation. At the core of trans-Tango is a synthetic signaling pathway that is introduced into all neurons in the animal. This pathway converts receptor activation at the cell surface into reporter expression through site-specific proteolysis. Specific labeling is achieved by presenting a tethered ligand at the synapses of genetically defined neurons, thereby activating the pathway in their postsynaptic partners and providing genetic access to these neurons. We first validated trans-Tango in the Drosophila olfactory system and then implemented it in the gustatory system, where projections beyond the first-order receptor neurons are not fully characterized. We identified putative second-order neurons within the sweet circuit that include projection neurons targeting known neuromodulation centers in the brain. These experiments establish trans-Tango as a flexible platform for transsynaptic circuit analysis.
Collapse
|
268
|
The morphology of antennal lobe projection neurons is controlled by a POU-domain transcription factor Bmacj6 in the silkmoth Bombyx mori. Sci Rep 2017; 7:14050. [PMID: 29070905 PMCID: PMC5656611 DOI: 10.1038/s41598-017-14578-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 10/12/2017] [Indexed: 11/08/2022] Open
Abstract
How to wire a neural circuit is crucial for the functioning of the nervous system. Here, we describe the neuroanatomy of the olfactory neurons in the spli mutant strain of silkmoth (Bombyx mori) to investigate the function of a transcription factor involved in neuronal wiring in the central olfactory circuit. The genomic structure of the gene Bmacj6, which encodes a class IV POU domain transcription factor, is disrupted in the spli mutant. We report the neuroanatomical abnormality in the morphology of the antennal lobe projection neurons (PNs) that process the sex pheromone. In addition to the mis-targeting of dendrites and axons, we found axonal bifurcation within the PNs. These results indicate that the morphology of neurons in the pheromone processing pathway is modified by Bmacj6.
Collapse
|
269
|
Bidaye SS, Bockemühl T, Büschges A. Six-legged walking in insects: how CPGs, peripheral feedback, and descending signals generate coordinated and adaptive motor rhythms. J Neurophysiol 2017; 119:459-475. [PMID: 29070634 DOI: 10.1152/jn.00658.2017] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Walking is a rhythmic locomotor behavior of legged animals, and its underlying mechanisms have been the subject of neurobiological research for more than 100 years. In this article, we review relevant historical aspects and contemporary studies in this field of research with a particular focus on the role of central pattern generating networks (CPGs) and their contribution to the generation of six-legged walking in insects. Aspects of importance are the generation of single-leg stepping, the generation of interleg coordination, and how descending signals influence walking. We first review how CPGs interact with sensory signals from the leg in the generation of leg stepping. Next, we summarize how these interactions are modified in the generation of motor flexibility for forward and backward walking, curve walking, and speed changes. We then review the present state of knowledge with regard to the role of CPGs in intersegmental coordination and how CPGs might be involved in mediating descending influences from the brain for the initiation, maintenance, modification, and cessation of the motor output for walking. Throughout, we aim to specifically address gaps in knowledge, and we describe potential future avenues and approaches, conceptual and methodological, with the latter emphasizing in particular options arising from the advent of neurogenetic approaches to this field of research and its combination with traditional approaches.
Collapse
Affiliation(s)
- Salil S Bidaye
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California
| | - Till Bockemühl
- Department of Animal Physiology, Zoological Institute, University of Cologne , Cologne , Germany
| | - Ansgar Büschges
- Department of Animal Physiology, Zoological Institute, University of Cologne , Cologne , Germany
| |
Collapse
|
270
|
Groothuis J, Smid HM. Nasonia Parasitic Wasps Escape from Haller's Rule by Diphasic, Partially Isometric Brain-Body Size Scaling and Selective Neuropil Adaptations. BRAIN, BEHAVIOR AND EVOLUTION 2017; 90:243-254. [PMID: 29059675 DOI: 10.1159/000480421] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/16/2017] [Indexed: 11/19/2022]
Abstract
Haller's rule states that brains scale allometrically with body size in all animals, meaning that relative brain size increases with decreasing body size. This rule applies both on inter- and intraspecific comparisons. Only 1 species, the extremely small parasitic wasp Trichogramma evanescens, is known as an exception and shows an isometric brain-body size relation in an intraspecific comparison between differently sized individuals. Here, we investigated if such an isometric brain-body size relationship also occurs in an intraspecific comparison with a slightly larger parasitic wasp, Nasonia vitripennis, a species that may vary 10-fold in body weight upon differences in levels of scramble competition during larval development. We show that Nasonia exhibits diphasic brain-body size scaling: larger wasps scale allometrically, following Haller's rule, whereas the smallest wasps show isometric scaling. Brains of smaller wasps are, therefore, smaller than expected and we hypothesized that this may lead to adaptations in brain architecture. Volumetric analysis of neuropil composition revealed that wasps of different sizes differed in relative volume of multiple neuropils. The optic lobes and mushroom bodies in particular were smaller in the smallest wasps. Furthermore, smaller brains had a relatively smaller total neuropil volume and larger cellular rind than large brains. These changes in relative brain size and brain architecture suggest that the energetic constraints on brain tissue outweigh specific cognitive requirements in small Nasonia wasps.
Collapse
Affiliation(s)
- Jitte Groothuis
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | | |
Collapse
|
271
|
Rittschof CC, Schirmeier S. Insect models of central nervous system energy metabolism and its links to behavior. Glia 2017; 66:1160-1175. [DOI: 10.1002/glia.23235] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/30/2017] [Accepted: 09/08/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Clare C. Rittschof
- Department of Entomology; College of Agriculture, Food, and the Environment, University of Kentucky; Lexington Kentucky
| | - Stefanie Schirmeier
- Institut für Neuro-und Verhaltensbiologie, University of Münster; Münster Germany
| |
Collapse
|
272
|
Wolff GH, Thoen HH, Marshall J, Sayre ME, Strausfeld NJ. An insect-like mushroom body in a crustacean brain. eLife 2017; 6:29889. [PMID: 28949916 PMCID: PMC5614564 DOI: 10.7554/elife.29889] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/25/2017] [Indexed: 01/02/2023] Open
Abstract
Mushroom bodies are the iconic learning and memory centers of insects. No previously described crustacean possesses a mushroom body as defined by strict morphological criteria although crustacean centers called hemiellipsoid bodies, which serve functions in sensory integration, have been viewed as evolutionarily convergent with mushroom bodies. Here, using key identifiers to characterize neural arrangements, we demonstrate insect-like mushroom bodies in stomatopod crustaceans (mantis shrimps). More than any other crustacean taxon, mantis shrimps display sophisticated behaviors relating to predation, spatial memory, and visual recognition comparable to those of insects. However, neuroanatomy-based cladistics suggesting close phylogenetic proximity of insects and stomatopod crustaceans conflicts with genomic evidence showing hexapods closely related to simple crustaceans called remipedes. We discuss whether corresponding anatomical phenotypes described here reflect the cerebral morphology of a common ancestor of Pancrustacea or an extraordinary example of convergent evolution. With more than four million species, arthropods are the largest and most diverse group of animals on the planet and include, for example, crustaceans, insects and spiders. They are defined by their segmented bodies, hard outer skeletons and jointed limbs. All arthropods share a common ancestor that lived more than 550 million years ago. Exactly how this ancestral arthropod gave rise to the myriad species that exist today is unclear but we know that at some point the arthropod family tree split into branches, one of which went on to become the crustaceans. The crustacean branch then split again, giving rise to a line of descendants that would become the insects. But although insects evolved from crustaceans, the brains of insects possess structures that those of crustaceans do not. Known as mushroom bodies, these structures help to form and store memories. Their absence in crustaceans has therefore been an enduring mystery. Wolff et al. now add a piece to the puzzle by showing that one group of modern-day crustaceans, the mantis shrimps, does in fact possess mushroom bodies. By visualizing cells and pathways within the brains of mantis shrimps, and also a number of closely related species, Wolff et al. show that only these shrimps possess true mushroom bodies. However, some of the mantis shrimp’s close relatives possess a few attributes of these structures. This suggests that mushroom bodies are evolutionarily ancient structures that arose in a common ancestor of insects and crustaceans, before being lost or radically modified in most of the crustaceans. So why did this happen? Mantis shrimps are top predators with excellent vision that hunt over considerable distances, requiring them to evaluate and memorize complex features of their environment. These cognitive demands, which might not be shared by other crustaceans, may have led to the mantis shrimps retaining their mushroom bodies. Further research into the brains and behavior of the mantis shrimp may provide insights into how mushroom bodies construct memories of a complex sensory world.
Collapse
Affiliation(s)
| | | | - Justin Marshall
- Sensory Neurobiology Group, University of Queensland, Brisbane, Australia
| | - Marcel E Sayre
- Department of Neuroscience, School of Mind, Brain and Behavior, University of Arizona, Tucson, United States
| | - Nicholas James Strausfeld
- Department of Neuroscience, School of Mind, Brain and Behavior, University of Arizona, Tucson, United States
| |
Collapse
|
273
|
Zhao XC, Xie GY, Berg BG, Schachtner J, Homberg U. Distribution of tachykinin-related peptides in the brain of the tobacco budworm Heliothis virescens. J Comp Neurol 2017; 525:3918-3934. [DOI: 10.1002/cne.24310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/06/2017] [Accepted: 08/22/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
- Chemosensory lab/Department of Psychology; Norwegian University of Science and Technology; Trondheim 7489 Norway
| | - Gui-Ying Xie
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Bente G. Berg
- Chemosensory lab/Department of Psychology; Norwegian University of Science and Technology; Trondheim 7489 Norway
| | - Joachim Schachtner
- Department of Biology, Animal Physiology; Philipps University; Marburg 35032 Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology; Philipps University; Marburg 35032 Germany
| |
Collapse
|
274
|
de Vries L, Pfeiffer K, Trebels B, Adden AK, Green K, Warrant E, Heinze S. Comparison of Navigation-Related Brain Regions in Migratory versus Non-Migratory Noctuid Moths. Front Behav Neurosci 2017; 11:158. [PMID: 28928641 PMCID: PMC5591330 DOI: 10.3389/fnbeh.2017.00158] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 08/15/2017] [Indexed: 11/13/2022] Open
Abstract
Brain structure and function are tightly correlated across all animals. While these relations are ultimately manifestations of differently wired neurons, many changes in neural circuit architecture lead to larger-scale alterations visible already at the level of brain regions. Locating such differences has served as a beacon for identifying brain areas that are strongly associated with the ecological needs of a species-thus guiding the way towards more detailed investigations of how brains underlie species-specific behaviors. Particularly in relation to sensory requirements, volume-differences in neural tissue between closely related species reflect evolutionary investments that correspond to sensory abilities. Likewise, memory-demands imposed by lifestyle have revealed similar adaptations in regions associated with learning. Whether this is also the case for species that differ in their navigational strategy is currently unknown. While the brain regions associated with navigational control in insects have been identified (central complex (CX), lateral complex (LX) and anterior optic tubercles (AOTU)), it remains unknown in what way evolutionary investments have been made to accommodate particularly demanding navigational strategies. We have thus generated average-shape atlases of navigation-related brain regions of a migratory and a non-migratory noctuid moth and used volumetric analysis to identify differences. We further compared the results to identical data from Monarch butterflies. Whereas we found differences in the size of the nodular unit of the AOTU, the LX and the protocerebral bridge (PB) between the two moths, these did not unambiguously reflect migratory behavior across all three species. We conclude that navigational strategy, at least in the case of long-distance migration in lepidopteran insects, is not easily deductible from overall neuropil anatomy. This suggests that the adaptations needed to ensure successful migratory behavior are found in the detailed wiring characteristics of the neural circuits underlying navigation-differences that are only accessible through detailed physiological and ultrastructural investigations. The presented results aid this task in two ways. First, the identified differences in neuropil volumes serve as promising initial targets for electrophysiology. Second, the new standard atlases provide an anatomical reference frame for embedding all functional data obtained from the brains of the Bogong and the Turnip moth.
Collapse
Affiliation(s)
- Liv de Vries
- Lund Vision Group, Department of Biology, Lund UniversityLund, Sweden
| | - Keram Pfeiffer
- Department of Biology, Marburg UniversityMarburg, Germany
| | - Björn Trebels
- Department of Biology, Marburg UniversityMarburg, Germany
| | - Andrea K Adden
- Lund Vision Group, Department of Biology, Lund UniversityLund, Sweden
| | - Ken Green
- New South Wales National Parks and Wildlife ServiceJindabyne, NSW, Australia
| | - Eric Warrant
- Lund Vision Group, Department of Biology, Lund UniversityLund, Sweden
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund UniversityLund, Sweden
| |
Collapse
|
275
|
Strube-Bloss MF, Grabe V, Hansson BS, Sachse S. Calcium imaging revealed no modulatory effect on odor-evoked responses of the Drosophila antennal lobe by two populations of inhibitory local interneurons. Sci Rep 2017; 7:7854. [PMID: 28798324 PMCID: PMC5552818 DOI: 10.1038/s41598-017-08090-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/06/2017] [Indexed: 12/26/2022] Open
Abstract
Although we have considerable knowledge about how odors are represented in the antennal lobe (AL), the insects’ analogue to the olfactory bulb, we still do not fully understand how the different neurons in the AL network contribute to the olfactory code. In Drosophila melanogaster we can selectively manipulate specific neuronal populations to elucidate their function in odor processing. Here we silenced the synaptic transmission of two distinct subpopulations of multiglomerular GABAergic local interneurons (LN1 and LN2) using shibire (shits) and analyzed their impact on odor-induced glomerular activity at the AL input and output level. We verified that the employed shits construct effectively blocked synaptic transmission to the AL when expressed in olfactory sensory neurons. Notably, selective silencing of both LN populations did not significantly affect the odor-evoked activity patterns in the AL. Neither the glomerular input nor the glomerular output activity was modulated in comparison to the parental controls. We therefore conclude that these LN subpopulations, which cover one third of the total LN number, are not predominantly involved in odor identity coding per se. As suggested by their broad innervation patterns and contribution to long-term adaptation, they might contribute to AL–computation on a global and longer time scale.
Collapse
Affiliation(s)
- Martin F Strube-Bloss
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, 07745, Jena, Germany.,Department of Behavioral Physiology & Sociobiology, Theodor-Boveri-Institute of Bioscience, Biocenter University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Veit Grabe
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Bill S Hansson
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Silke Sachse
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
| |
Collapse
|
276
|
Ngo KT, Andrade I, Hartenstein V. Spatio-temporal pattern of neuronal differentiation in the Drosophila visual system: A user's guide to the dynamic morphology of the developing optic lobe. Dev Biol 2017; 428:1-24. [PMID: 28533086 PMCID: PMC5825191 DOI: 10.1016/j.ydbio.2017.05.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/08/2017] [Accepted: 05/09/2017] [Indexed: 11/20/2022]
Abstract
Visual information processing in animals with large image forming eyes is carried out in highly structured retinotopically ordered neuropils. Visual neuropils in Drosophila form the optic lobe, which consists of four serially arranged major subdivisions; the lamina, medulla, lobula and lobula plate; the latter three of these are further subdivided into multiple layers. The visual neuropils are formed by more than 100 different cell types, distributed and interconnected in an invariant highly regular pattern. This pattern relies on a protracted sequence of developmental steps, whereby different cell types are born at specific time points and nerve connections are formed in a tightly controlled sequence that has to be coordinated among the different visual neuropils. The developing fly visual system has become a highly regarded and widely studied paradigm to investigate the genetic mechanisms that control the formation of neural circuits. However, these studies are often made difficult by the complex and shifting patterns in which different types of neurons and their connections are distributed throughout development. In the present paper we have reconstructed the three-dimensional architecture of the Drosophila optic lobe from the early larva to the adult. Based on specific markers, we were able to distinguish the populations of progenitors of the four optic neuropils and map the neurons and their connections. Our paper presents sets of annotated confocal z-projections and animated 3D digital models of these structures for representative stages. The data reveal the temporally coordinated growth of the optic neuropils, and clarify how the position and orientation of the neuropils and interconnecting tracts (inner and outer optic chiasm) changes over time. Finally, we have analyzed the emergence of the discrete layers of the medulla and lobula complex using the same markers (DN-cadherin, Brp) employed to systematically explore the structure and development of the central brain neuropil. Our work will facilitate experimental studies of the molecular mechanisms regulating neuronal fate and connectivity in the fly visual system, which bears many fundamental similarities with the retina of vertebrates.
Collapse
Affiliation(s)
- Kathy T Ngo
- Department of Molecular, Cell, and Developmental Biology, United States
| | - Ingrid Andrade
- Department of Molecular, Cell, and Developmental Biology, United States
| | - Volker Hartenstein
- Department of Molecular, Cell, and Developmental Biology, United States; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States.
| |
Collapse
|
277
|
Robie AA, Hirokawa J, Edwards AW, Umayam LA, Lee A, Phillips ML, Card GM, Korff W, Rubin GM, Simpson JH, Reiser MB, Branson K. Mapping the Neural Substrates of Behavior. Cell 2017; 170:393-406.e28. [PMID: 28709004 DOI: 10.1016/j.cell.2017.06.032] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/01/2017] [Accepted: 06/19/2017] [Indexed: 11/20/2022]
Abstract
Assigning behavioral functions to neural structures has long been a central goal in neuroscience and is a necessary first step toward a circuit-level understanding of how the brain generates behavior. Here, we map the neural substrates of locomotion and social behaviors for Drosophila melanogaster using automated machine-vision and machine-learning techniques. From videos of 400,000 flies, we quantified the behavioral effects of activating 2,204 genetically targeted populations of neurons. We combined a novel quantification of anatomy with our behavioral analysis to create brain-behavior correlation maps, which are shared as browsable web pages and interactive software. Based on these maps, we generated hypotheses of regions of the brain causally related to sensory processing, locomotor control, courtship, aggression, and sleep. Our maps directly specify genetic tools to target these regions, which we used to identify a small population of neurons with a role in the control of walking.
Collapse
Affiliation(s)
- Alice A Robie
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Jonathan Hirokawa
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA; Laboratory of Integrative Brain Function, The Rockefeller University, New York, NY, USA
| | - Austin W Edwards
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Lowell A Umayam
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Allen Lee
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Mary L Phillips
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA; Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Gwyneth M Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Wyatt Korff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Julie H Simpson
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA; Department of Molecular, Cellular, and Developmental Biology, UC Santa Barbara, Santa Barbara, CA, USA
| | - Michael B Reiser
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Kristin Branson
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
| |
Collapse
|
278
|
Whole-Brain Calcium Imaging Reveals an Intrinsic Functional Network in Drosophila. Curr Biol 2017; 27:2389-2396.e4. [PMID: 28756955 DOI: 10.1016/j.cub.2017.06.076] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/09/2017] [Accepted: 06/29/2017] [Indexed: 02/07/2023]
Abstract
A long-standing goal of neuroscience has been to understand how computations are implemented across large-scale brain networks. By correlating spontaneous activity during "resting states" [1], studies of intrinsic brain networks in humans have demonstrated a correspondence with task-related activation patterns [2], relationships to behavior [3], and alterations in processes such as aging [4] and brain disorders [5], highlighting the importance of resting-state measurements for understanding brain function. Here, we develop methods to measure intrinsic functional connectivity in Drosophila, a powerful model for the study of neural computation. Recent studies using calcium imaging have measured neural activity at high spatial and temporal resolution in zebrafish, Drosophila larvae, and worms [6-10]. For example, calcium imaging in the zebrafish brain recently revealed correlations between the midbrain and hindbrain, demonstrating the utility of measuring intrinsic functional connections in model organisms [8]. An important component of human connectivity research is the use of brain atlases to compare findings across individuals and studies [11]. An anatomical atlas of the central adult fly brain was recently described [12]; however, combining an atlas with whole-brain calcium imaging has yet to be performed in vivo in adult Drosophila. Here, we measure intrinsic functional connectivity in Drosophila by acquiring calcium signals from the central brain. We develop an alignment procedure to assign functional data to atlas regions and correlate activity between regions to generate brain networks. This work reveals a large-scale architecture for neural communication and provides a framework for using Drosophila to study functional brain networks.
Collapse
|
279
|
Tedjakumala SR, Rouquette J, Boizeau ML, Mesce KA, Hotier L, Massou I, Giurfa M. A Tyrosine-Hydroxylase Characterization of Dopaminergic Neurons in the Honey Bee Brain. Front Syst Neurosci 2017; 11:47. [PMID: 28740466 PMCID: PMC5502285 DOI: 10.3389/fnsys.2017.00047] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/09/2017] [Indexed: 11/13/2022] Open
Abstract
Dopamine (DA) plays a fundamental role in insect behavior as it acts both as a general modulator of behavior and as a value system in associative learning where it mediates the reinforcing properties of unconditioned stimuli (US). Here we aimed at characterizing the dopaminergic neurons in the central nervous system of the honey bee, an insect that serves as an established model for the study of learning and memory. We used tyrosine hydroxylase (TH) immunoreactivity (ir) to ensure that the neurons detected synthesize DA endogenously. We found three main dopaminergic clusters, C1-C3, which had been previously described; the C1 cluster is located in a small region adjacent to the esophagus (ES) and the antennal lobe (AL); the C2 cluster is situated above the C1 cluster, between the AL and the vertical lobe (VL) of the mushroom body (MB); the C3 cluster is located below the calyces (CA) of the MB. In addition, we found a novel dopaminergic cluster, C4, located above the dorsomedial border of the lobula, which innervates the visual neuropils of the bee brain. Additional smaller processes and clusters were found and are described. The profuse dopaminergic innervation of the entire bee brain and the specific connectivity of DA neurons, with visual, olfactory and gustatory circuits, provide a foundation for a deeper understanding of how these sensory modules are modulated by DA, and the DA-dependent value-based associations that occur during associative learning.
Collapse
Affiliation(s)
- Stevanus R Tedjakumala
- Research Centre on Animal Cognition, Center for Integrative Biology, Centre National de la Recherche Scientifique (CNRS), University of ToulouseToulouse, France
| | - Jacques Rouquette
- Advanced Technology Institute in Life Sciences (ITAV), Centre National de la Recherche Scientifique-Université Paul Sabatier Toulouse III (CNRS-UPS), Université Paul Sabatier Toulouse III (UPS), Université de ToulouseToulouse, France
| | - Marie-Laure Boizeau
- Advanced Technology Institute in Life Sciences (ITAV), Centre National de la Recherche Scientifique-Université Paul Sabatier Toulouse III (CNRS-UPS), Université Paul Sabatier Toulouse III (UPS), Université de ToulouseToulouse, France
| | - Karen A Mesce
- Department of Entomology, University of MinnesotaSaint Paul, MN, United States
| | - Lucie Hotier
- Research Centre on Animal Cognition, Center for Integrative Biology, Centre National de la Recherche Scientifique (CNRS), University of ToulouseToulouse, France
| | - Isabelle Massou
- Research Centre on Animal Cognition, Center for Integrative Biology, Centre National de la Recherche Scientifique (CNRS), University of ToulouseToulouse, France
| | - Martin Giurfa
- Research Centre on Animal Cognition, Center for Integrative Biology, Centre National de la Recherche Scientifique (CNRS), University of ToulouseToulouse, France
| |
Collapse
|
280
|
Boyan G, Liu Y, Khalsa SK, Hartenstein V. A conserved plan for wiring up the fan-shaped body in the grasshopper and Drosophila. Dev Genes Evol 2017; 227:253-269. [PMID: 28752327 PMCID: PMC5813802 DOI: 10.1007/s00427-017-0587-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 07/10/2017] [Indexed: 01/07/2023]
Abstract
The central complex comprises an elaborate system of modular neuropils which mediate spatial orientation and sensory-motor integration in insects such as the grasshopper and Drosophila. The neuroarchitecture of the largest of these modules, the fan-shaped body, is characterized by its stereotypic set of decussating fiber bundles. These are generated during development by axons from four homologous protocerebral lineages which enter the commissural system and subsequently decussate at stereotypic locations across the brain midline. Since the commissural organization prior to fan-shaped body formation has not been previously analyzed in either species, it was not clear how the decussating bundles relate to individual lineages, or if the projection pattern is conserved across species. In this study, we trace the axonal projections from the homologous central complex lineages into the commissural system of the embryonic and larval brains of both the grasshopper and Drosophila. Projections into the primordial commissures of both species are found to be lineage-specific and allow putatively equivalent fascicles to be identified. Comparison of the projection pattern before and after the commencement of axon decussation in both species reveals that equivalent commissural fascicles are involved in generating the columnar neuroarchitecture of the fan-shaped body. Further, the tract-specific columns in both the grasshopper and Drosophila can be shown to contain axons from identical combinations of central complex lineages, suggesting that this columnar neuroarchitecture is also conserved.
Collapse
Affiliation(s)
- George Boyan
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität, Grosshadernerstrasse 2, 82152, Planegg-Martinsried, Germany
| | - Yu Liu
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität, Grosshadernerstrasse 2, 82152, Planegg-Martinsried, Germany
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, North Cuihu Road 2, Kunming, 650091, China
| | - Sat Kartar Khalsa
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA.
| |
Collapse
|
281
|
Identified Serotonergic Modulatory Neurons Have Heterogeneous Synaptic Connectivity within the Olfactory System of Drosophila. J Neurosci 2017; 37:7318-7331. [PMID: 28659283 DOI: 10.1523/jneurosci.0192-17.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 05/20/2017] [Accepted: 06/19/2017] [Indexed: 11/21/2022] Open
Abstract
Modulatory neurons project widely throughout the brain, dynamically altering network processing based on an animal's physiological state. The connectivity of individual modulatory neurons can be complex, as they often receive input from a variety of sources and are diverse in their physiology, structure, and gene expression profiles. To establish basic principles about the connectivity of individual modulatory neurons, we examined a pair of identified neurons, the "contralaterally projecting, serotonin-immunoreactive deutocerebral neurons" (CSDns), within the olfactory system of Drosophila Specifically, we determined the neuronal classes providing synaptic input to the CSDns within the antennal lobe (AL), an olfactory network targeted by the CSDns, and the degree to which CSDn active zones are uniformly distributed across the AL. Using anatomical techniques, we found that the CSDns received glomerulus-specific input from olfactory receptor neurons (ORNs) and projection neurons (PNs), and networkwide input from local interneurons (LNs). Furthermore, we quantified the number of CSDn active zones in each glomerulus and found that CSDn output is not uniform, but rather heterogeneous, across glomeruli and stereotyped from animal to animal. Finally, we demonstrate that the CSDns synapse broadly onto LNs and PNs throughout the AL but do not synapse upon ORNs. Our results demonstrate that modulatory neurons do not necessarily provide purely top-down input but rather receive neuron class-specific input from the networks that they target, and that even a two cell modulatory network has highly heterogeneous, yet stereotyped, pattern of connectivity.SIGNIFICANCE STATEMENT Modulatory neurons often project broadly throughout the brain to alter processing based on physiological state. However, the connectivity of individual modulatory neurons to their target networks is not well understood, as modulatory neuron populations are heterogeneous in their physiology, morphology, and gene expression. In this study, we use a pair of identified serotonergic neurons within the Drosophila olfactory system as a model to establish a framework for modulatory neuron connectivity. We demonstrate that individual modulatory neurons can integrate neuron class-specific input from their target network, which is often nonreciprocal. Additionally, modulatory neuron output can be stereotyped, yet nonuniform, across network regions. Our results provide new insight into the synaptic relationships that underlie network function of modulatory neurons.
Collapse
|
282
|
Anatomical Reconstruction and Functional Imaging Reveal an Ordered Array of Skylight Polarization Detectors in Drosophila. J Neurosci 2017; 36:5397-404. [PMID: 27170135 DOI: 10.1523/jneurosci.0310-16.2016] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/06/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Many insects exploit skylight polarization as a compass cue for orientation and navigation. In the fruit fly, Drosophila melanogaster, photoreceptors R7 and R8 in the dorsal rim area (DRA) of the compound eye are specialized to detect the electric vector (e-vector) of linearly polarized light. These photoreceptors are arranged in stacked pairs with identical fields of view and spectral sensitivities, but mutually orthogonal microvillar orientations. As in larger flies, we found that the microvillar orientation of the distal photoreceptor R7 changes in a fan-like fashion along the DRA. This anatomical arrangement suggests that the DRA constitutes a detector for skylight polarization, in which different e-vectors maximally excite different positions in the array. To test our hypothesis, we measured responses to polarized light of varying e-vector angles in the terminals of R7/8 cells using genetically encoded calcium indicators. Our data confirm a progression of preferred e-vector angles from anterior to posterior in the DRA, and a strict orthogonality between the e-vector preferences of paired R7/8 cells. We observed decreased activity in photoreceptors in response to flashes of light polarized orthogonally to their preferred e-vector angle, suggesting reciprocal inhibition between photoreceptors in the same medullar column, which may serve to increase polarization contrast. Together, our results indicate that the polarization-vision system relies on a spatial map of preferred e-vector angles at the earliest stage of sensory processing. SIGNIFICANCE STATEMENT The fly's visual system is an influential model system for studying neural computation, and much is known about its anatomy, physiology, and development. The circuits underlying motion processing have received the most attention, but researchers are increasingly investigating other functions, such as color perception and object recognition. In this work, we investigate the early neural processing of a somewhat exotic sense, called polarization vision. Because skylight is polarized in an orientation that is rigidly determined by the position of the sun, this cue provides compass information. Behavioral experiments have shown that many species use the polarization pattern in the sky to direct locomotion. Here we describe the input stage of the fly's polarization-vision system.
Collapse
|
283
|
Thoen HH, Strausfeld NJ, Marshall J. Neural organization of afferent pathways from the stomatopod compound eye. J Comp Neurol 2017; 525:3010-3030. [PMID: 28577301 DOI: 10.1002/cne.24256] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/25/2017] [Accepted: 05/16/2017] [Indexed: 01/01/2023]
Abstract
Crustaceans and insects share many similarities of brain organization suggesting that their common ancestor possessed some components of those shared features. Stomatopods (mantis shrimps) are basal eumalacostracan crustaceans famous for their elaborate visual system, the most complex of which possesses 12 types of color photoreceptors and the ability to detect both linearly and circularly polarized light. Here, using a palette of histological methods we describe neurons and their neuropils most immediately associated with the stomatopod retina. We first provide a general overview of the major neuropil structures in the eyestalks lateral protocerebrum, with respect to the optical pathways originating from the six rows of specialized ommatidia in the stomatopod's eye, termed the midband. We then focus on the structure and neuronal types of the lamina, the first optic neuropil in the stomatopod visual system. Using Golgi impregnations to resolve single neurons we identify cells in different parts of the lamina corresponding to the three different regions of the stomatopod eye (midband and the upper and lower eye halves). While the optic cartridges relating to the spectral and polarization sensitive midband ommatidia show some specializations not found in the lamina serving the upper and lower eye halves, the general morphology of the midband lamina reflects cell types elsewhere in the lamina and cell types described for other species of Eumalacostraca.
Collapse
Affiliation(s)
- Hanne H Thoen
- Sensory Neurobiology Group, Queensland Brain Institute, University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia
| | - Nicholas J Strausfeld
- Department of Neuroscience, School of Mind, Brain and Behavior, University of Arizona, Tucson, Arizona, 85721
| | - Justin Marshall
- Sensory Neurobiology Group, Queensland Brain Institute, University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia
| |
Collapse
|
284
|
Kamhi JF, Sandridge-Gresko A, Walker C, Robson SKA, Traniello JFA. Worker brain development and colony organization in ants: Does division of labor influence neuroplasticity? Dev Neurobiol 2017; 77:1072-1085. [PMID: 28276652 DOI: 10.1002/dneu.22496] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/24/2017] [Accepted: 02/25/2017] [Indexed: 01/09/2023]
Abstract
Brain compartment size allometries may adaptively reflect cognitive needs associated with behavioral development and ecology. Ants provide an informative system to study the relationship of neural architecture and development because worker tasks and sensory inputs may change with age. Additionally, tasks may be divided among morphologically and behaviorally differentiated worker groups (subcastes), reducing repertoire size through specialization and aligning brain structure with task-specific cognitive requirements. We hypothesized that division of labor may decrease developmental neuroplasticity in workers due to the apparently limited behavioral flexibility associated with task specialization. To test this hypothesis, we compared macroscopic and cellular neuroanatomy in two ant sister clades with striking contrasts in worker morphological differentiation and colony-level social organization: Oecophylla smaragdina, a socially complex species with large colonies and behaviorally distinct dimorphic workers, and Formica subsericea, a socially basic species with small colonies containing monomorphic workers. We quantified volumes of functionally distinct brain compartments in newly eclosed and mature workers and measured the effects of visual experience on synaptic complex (microglomeruli) organization in the mushroom bodies-regions of higher-order sensory integration-to determine the extent of experience-dependent neuroplasticity. We demonstrate that, contrary to our hypothesis, O. smaragdina workers have significant age-related volume increases and synaptic reorganization in the mushroom bodies, whereas F. subsericea workers have reduced age-related neuroplasticity. We also found no visual experience-dependent synaptic reorganization in either species. Our findings thus suggest that changes in the mushroom body with age are associated with division of labor, and therefore social complexity, in ants. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1072-1085, 2017.
Collapse
Affiliation(s)
- J Frances Kamhi
- Department of Biology, Boston University, Boston, Massachusetts, 02215.,Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, 02215
| | - Aynsley Sandridge-Gresko
- Department of Natural Sciences and Mathematics, Lesley University, Cambridge, Massachusetts, 02138
| | - Christina Walker
- Department of Biology, Boston University, Boston, Massachusetts, 02215
| | - Simon K A Robson
- Zoology and Ecology, James Cook University, Townsville, Queensland, 4811, Australia
| | - James F A Traniello
- Department of Biology, Boston University, Boston, Massachusetts, 02215.,Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, 02215
| |
Collapse
|
285
|
Xie X, Tabuchi M, Brown MP, Mitchell SP, Wu MN, Kolodkin AL. The laminar organization of the Drosophila ellipsoid body is semaphorin-dependent and prevents the formation of ectopic synaptic connections. eLife 2017. [PMID: 28632130 PMCID: PMC5511011 DOI: 10.7554/elife.25328] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The ellipsoid body (EB) in the Drosophila brain is a central complex (CX) substructure that harbors circumferentially laminated ring (R) neuron axons and mediates multifaceted sensory integration and motor coordination functions. However, what regulates R axon lamination and how lamination affects R neuron function remain unknown. We show here that the EB is sequentially innervated by small-field and large-field neurons and that early developing EB neurons play an important regulatory role in EB laminae formation. The transmembrane proteins semaphorin-1a (Sema-1a) and plexin A function together to regulate R axon lamination. R neurons recruit both GABA and GABA-A receptors to their axon terminals in the EB, and optogenetic stimulation coupled with electrophysiological recordings show that Sema-1a-dependent R axon lamination is required for preventing the spread of synaptic inhibition between adjacent EB lamina. These results provide direct evidence that EB lamination is critical for local pre-synaptic inhibitory circuit organization. DOI:http://dx.doi.org/10.7554/eLife.25328.001 The human brain contains around one hundred billion nerve cells, or neurons, which are interconnected and organized into distinct layers within different brain regions. Electrical impulses pass along a cable-like part of each neuron, known as the axon, to reach other neurons in different layers of various brain structures. The brain of a fruit fly contains fewer neurons – about 100 thousand in total – but it still establishes precise connections among neurons in different brain layers. In both flies and humans, axons grow along set paths to reach their targets by following guidance cues. Many of these cues are conserved between insects and mammals, including proteins belonging to the semaphorin family. These proteins work together to steer growing axons towards their proper targets and repel them away from the incorrect ones. However, how neurons establish connections in specific layers remains poorly understood. In the middle of the fruit fly brain lies a donut-shaped structure called the ellipsoid body, which the fly needs to navigate the world around it. The ellipsoid body contains a group of neurons that extend their axons to form multiple concentric rings. Xie et al. have now asked how the different “ring neurons” are organized in the ellipsoid body and how this sort of organization affects the connections between the neurons. Imaging techniques were used to visualize the layered organization of different ring neurons and to track their growing axons. Further work showed that this organization depends on semaphorin signaling, because when this pathway was disrupted, the layered pattern did not develop properly. This in turn, caused the axons of the ring neuron to wander out of their correct concentric ring and connect with the wrong targets in adjacent rings. Together these findings show that neurons rely on evolutionarily conserved semaphorins to correctly organize themselves into layers and connect with the appropriate targets. Further work is now needed to identify additional proteins that are critical for fly brains to form layered structures, and to understand how this layered organization influences how an animal behaves. DOI:http://dx.doi.org/10.7554/eLife.25328.002
Collapse
Affiliation(s)
- Xiaojun Xie
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Masashi Tabuchi
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Matthew P Brown
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Sarah P Mitchell
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Mark N Wu
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Alex L Kolodkin
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, United States
| |
Collapse
|
286
|
Thamm M, Scholl C, Reim T, Grübel K, Möller K, Rössler W, Scheiner R. Neuronal distribution of tyramine and the tyramine receptor AmTAR1 in the honeybee brain. J Comp Neurol 2017; 525:2615-2631. [DOI: 10.1002/cne.24228] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/19/2017] [Accepted: 04/20/2017] [Indexed: 01/28/2023]
Affiliation(s)
- Markus Thamm
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Christina Scholl
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Tina Reim
- Animal Physiology, Institute for Biochemistry and Biology, University of PotsdamPotsdam Germany
| | - Kornelia Grübel
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Karin Möller
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Wolfgang Rössler
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| | - Ricarda Scheiner
- Behavioral Physiology & SociobiologyBiocenter, University of WürzburgAm Hubland Würzburg Germany
| |
Collapse
|
287
|
Watanabe H, Nishino H, Mizunami M, Yokohari F. Two Parallel Olfactory Pathways for Processing General Odors in a Cockroach. Front Neural Circuits 2017; 11:32. [PMID: 28529476 PMCID: PMC5418552 DOI: 10.3389/fncir.2017.00032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/18/2017] [Indexed: 11/23/2022] Open
Abstract
In animals, sensory processing via parallel pathways, including the olfactory system, is a common design. However, the mechanisms that parallel pathways use to encode highly complex and dynamic odor signals remain unclear. In the current study, we examined the anatomical and physiological features of parallel olfactory pathways in an evolutionally basal insect, the cockroach Periplaneta americana. In this insect, the entire system for processing general odors, from olfactory sensory neurons to higher brain centers, is anatomically segregated into two parallel pathways. Two separate populations of secondary olfactory neurons, type1 and type2 projection neurons (PNs), with dendrites in distinct glomerular groups relay olfactory signals to segregated areas of higher brain centers. We conducted intracellular recordings, revealing olfactory properties and temporal patterns of both types of PNs. Generally, type1 PNs exhibit higher odor-specificities to nine tested odorants than type2 PNs. Cluster analyses revealed that odor-evoked responses were temporally complex and varied in type1 PNs, while type2 PNs exhibited phasic on-responses with either early or late latencies to an effective odor. The late responses are 30–40 ms later than the early responses. Simultaneous intracellular recordings from two different PNs revealed that a given odor activated both types of PNs with different temporal patterns, and latencies of early and late responses in type2 PNs might be precisely controlled. Our results suggest that the cockroach is equipped with two anatomically and physiologically segregated parallel olfactory pathways, which might employ different neural strategies to encode odor information.
Collapse
Affiliation(s)
- Hidehiro Watanabe
- Division of Biology, Department of Earth System Science, Fukuoka UniversityFukuoka, Japan
| | - Hiroshi Nishino
- Research Institute for Electronic Science, Hokkaido UniversitySapporo, Japan
| | | | - Fumio Yokohari
- Division of Biology, Department of Earth System Science, Fukuoka UniversityFukuoka, Japan
| |
Collapse
|
288
|
Martín-Vega D, Simonsen TJ, Wicklein M, Hall MJR. Age estimation during the blow fly intra-puparial period: a qualitative and quantitative approach using micro-computed tomography. Int J Legal Med 2017; 131:1429-1448. [PMID: 28474172 PMCID: PMC5556140 DOI: 10.1007/s00414-017-1598-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/20/2017] [Indexed: 12/12/2022]
Abstract
Minimum post-mortem interval (minPMI) estimates often rely on the use of developmental data from blow flies (Diptera: Calliphoridae), which are generally the first colonisers of cadavers and, therefore, exemplar forensic indicators. Developmental data of the intra-puparial period are of particular importance, as it can account for more than half of the developmental duration of the blow fly life cycle. During this period, the insect undergoes metamorphosis inside the opaque, barrel-shaped puparium, formed by the hardening and darkening of the third instar larval cuticle, which shows virtually no external changes until adult emergence. Regrettably, estimates based on the intra-puparial period are severely limited due to the lack of reliable, non-destructive ageing methods and are frequently based solely on qualitative developmental markers. In this study, we use non-destructive micro-computed tomography (micro-CT) for (i) performing qualitative and quantitative analyses of the morphological changes taking place during the intra-puparial period of two forensically relevant blow fly species, Calliphora vicina and Lucilia sericata, and (ii) developing a novel and reliable method for estimating insect age in forensic practice. We show that micro-CT provides age-diagnostic qualitative characters for most 10% time intervals of the total intra-puparial period, which can be used over a range of temperatures and with a resolution comparable to more invasive and time-consuming traditional imaging techniques. Moreover, micro-CT can be used to yield a quantitative measure of the development of selected organ systems to be used in combination with qualitative markers. Our results confirm micro-CT as an emerging, powerful tool in medico-legal investigations.
Collapse
Affiliation(s)
- Daniel Martín-Vega
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
| | | | - Martina Wicklein
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
| | - Martin J R Hall
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| |
Collapse
|
289
|
Tang X, Roessingh S, Hayley SE, Chu ML, Tanaka NK, Wolfgang W, Song S, Stanewsky R, Hamada FN. The role of PDF neurons in setting the preferred temperature before dawn in Drosophila. eLife 2017; 6. [PMID: 28463109 PMCID: PMC5449184 DOI: 10.7554/elife.23206] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 04/23/2017] [Indexed: 12/02/2022] Open
Abstract
Animals have sophisticated homeostatic controls. While mammalian body temperature fluctuates throughout the day, small ectotherms, such as Drosophila achieve a body temperature rhythm (BTR) through their preference of environmental temperature. Here, we demonstrate that pigment dispersing factor (PDF) neurons play an important role in setting preferred temperature before dawn. We show that small lateral ventral neurons (sLNvs), a subset of PDF neurons, activate the dorsal neurons 2 (DN2s), the main circadian clock cells that regulate temperature preference rhythm (TPR). The number of temporal contacts between sLNvs and DN2s peak before dawn. Our data suggest that the thermosensory anterior cells (ACs) likely contact sLNvs via serotonin signaling. Together, the ACs-sLNs-DN2s neural circuit regulates the proper setting of temperature preference before dawn. Given that sLNvs are important for sleep and that BTR and sleep have a close temporal relationship, our data highlight a possible neuronal interaction between body temperature and sleep regulation. DOI:http://dx.doi.org/10.7554/eLife.23206.001
Collapse
Affiliation(s)
- Xin Tang
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, Cincinnati, United States
| | - Sanne Roessingh
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Sean E Hayley
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, Cincinnati, United States
| | - Michelle L Chu
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, Cincinnati, United States
| | - Nobuaki K Tanaka
- Creative Research Institution, Hokkaido University, Sapporo, Japan.,PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Werner Wolfgang
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Seongho Song
- Department of Mathematical Sciences, University of Cincinnati, Cincinnati, United States
| | - Ralf Stanewsky
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Fumika N Hamada
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, Cincinnati, United States.,PRESTO, Japan Science and Technology Agency, Saitama, Japan.,Department of Ophthalmology, College of Medicine, University of Cincinnati, Cincinnati, United States.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, United States
| |
Collapse
|
290
|
Genes and neural circuits for sleep of the fruit fly. Neurosci Res 2017; 118:82-91. [DOI: 10.1016/j.neures.2017.04.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/29/2017] [Accepted: 03/29/2017] [Indexed: 02/07/2023]
|
291
|
Paeger L, Bardos V, Kloppenburg P. Transient voltage-activated K + currents in central antennal lobe neurons: cell type-specific functional properties. J Neurophysiol 2017; 117:2053-2064. [PMID: 28179480 PMCID: PMC5434483 DOI: 10.1152/jn.00685.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 02/01/2023] Open
Abstract
In this study we analyzed transient voltage-activated K+ currents (IA) of projection neurons and local interneurons in the antennal lobe of the cockroach Periplaneta americana The antennal lobe is the first synaptic processing station for olfactory information in insects. Local interneurons are crucial for computing olfactory information and form local synaptic connections exclusively in the antennal lobe, whereas a primary task of the projection neurons is the transfer of preprocessed olfactory information from the antennal lobe to higher order centers in the protocerebrum. The different physiological tasks of these neurons require specialized physiological and morphological neuronal phenotypes. We asked if and how the different physiological phenotypes are reflected in the functional properties of IA, which is crucial for shaping intrinsic electrophysiological properties of neurons. Whole cell patch-clamp recordings from adult male P. americana showed that all their central antennal lobe neurons can generate IA The current exhibited marked cell type-specific differences in voltage dependence of steady-state activation and inactivation, and differences in inactivation kinetics during sustained depolarization. Pharmacological experiments revealed that IA in all neuron types was partially blocked by α-dendrotoxin and phrixotoxin-2, which are considered blockers with specificity for Shaker- and Shal-type channels, respectively. These findings suggest that IA in each cell type is a mixed current generated by channels of both families. The functional role of IA was analyzed in experiments under current clamp, in which portions of IA were blocked by α-dendrotoxin or phrixotoxin-2. These experiments showed that IA contributes significantly to the intrinsic electrophysiological properties, such as the action potential waveform and membrane excitability.NEW & NOTEWORTHY In the insect olfactory system, projection neurons and local interneurons have task-specific electrophysiological and morphological phenotypes. Voltage-activated potassium channels play a crucial role in shaping functional properties of these neurons. This study revealed marked cell type-specific differences in the biophysical properties of transient voltage-activated potassium currents in central antennal lobe neurons.
Collapse
Affiliation(s)
- Lars Paeger
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Viktor Bardos
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Peter Kloppenburg
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| |
Collapse
|
292
|
Age-associated increase of the active zone protein Bruchpilot within the honeybee mushroom body. PLoS One 2017; 12:e0175894. [PMID: 28437454 PMCID: PMC5402947 DOI: 10.1371/journal.pone.0175894] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/02/2017] [Indexed: 01/07/2023] Open
Abstract
In honeybees, age-associated structural modifications can be observed in the mushroom bodies. Prominent examples are the synaptic complexes (microglomeruli, MG) in the mushroom body calyces, which were shown to alter their size and density with age. It is not known whether the amount of intracellular synaptic proteins in the MG is altered as well. The presynaptic protein Bruchpilot (BRP) is localized at active zones and is involved in regulating the probability of neurotransmitter release in the fruit fly, Drosophila melanogaster. Here, we explored the localization of the honeybee BRP (Apis mellifera BRP, AmBRP) in the bee brain and examined age-related changes in the AmBRP abundance in the central bee brain and in microglomeruli of the mushroom body calyces. We report predominant AmBRP localization near the membrane of presynaptic boutons within the mushroom body MG. The relative amount of AmBRP was increased in the central brain of two-week old bees whereas the amount of Synapsin, another presynaptic protein involved in the regulation of neurotransmitter release, shows an increase during the first two weeks followed by a decrease. In addition, we demonstrate an age-associated modulation of AmBRP located near the membrane of presynaptic boutons within MG located in mushroom body calyces where sensory input is conveyed to mushroom body intrinsic neurons. We discuss that the observed age-associated AmBRP modulation might be related to maturation processes or to homeostatic mechanisms that might help to maintain synaptic functionality in old animals.
Collapse
|
293
|
Omoto JJ, Keleş MF, Nguyen BCM, Bolanos C, Lovick JK, Frye MA, Hartenstein V. Visual Input to the Drosophila Central Complex by Developmentally and Functionally Distinct Neuronal Populations. Curr Biol 2017; 27:1098-1110. [PMID: 28366740 PMCID: PMC5446208 DOI: 10.1016/j.cub.2017.02.063] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 02/24/2017] [Accepted: 02/27/2017] [Indexed: 01/05/2023]
Abstract
The Drosophila central brain consists of stereotyped neural lineages, developmental-structural units of macrocircuitry formed by the sibling neurons of single progenitors called neuroblasts. We demonstrate that the lineage principle guides the connectivity and function of neurons, providing input to the central complex, a collection of neuropil compartments important for visually guided behaviors. One of these compartments is the ellipsoid body (EB), a structure formed largely by the axons of ring (R) neurons, all of which are generated by a single lineage, DALv2. Two further lineages, DALcl1 and DALcl2, produce neurons that connect the anterior optic tubercle, a central brain visual center, with R neurons. Finally, DALcl1/2 receive input from visual projection neurons of the optic lobe medulla, completing a three-legged circuit that we call the anterior visual pathway (AVP). The AVP bears a fundamental resemblance to the sky-compass pathway, a visual navigation circuit described in other insects. Neuroanatomical analysis and two-photon calcium imaging demonstrate that DALcl1 and DALcl2 form two parallel channels, establishing connections with R neurons located in the peripheral and central domains of the EB, respectively. Although neurons of both lineages preferentially respond to bright objects, DALcl1 neurons have small ipsilateral, retinotopically ordered receptive fields, whereas DALcl2 neurons share a large excitatory receptive field in the contralateral hemifield. DALcl2 neurons become inhibited when the object enters the ipsilateral hemifield and display an additional excitation after the object leaves the field of view. Thus, the spatial position of a bright feature, such as a celestial body, may be encoded within this pathway.
Collapse
Affiliation(s)
- Jaison Jiro Omoto
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mehmet Fatih Keleş
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Bao-Chau Minh Nguyen
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Cheyenne Bolanos
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jennifer Kelly Lovick
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mark Arthur Frye
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
294
|
Rosner R, von Hadeln J, Salden T, Homberg U. Anatomy of the lobula complex in the brain of the praying mantis compared to the lobula complexes of the locust and cockroach. J Comp Neurol 2017; 525:2343-2357. [PMID: 28295329 PMCID: PMC5435961 DOI: 10.1002/cne.24208] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 12/30/2022]
Abstract
The praying mantis is an insect which relies on vision for capturing prey, avoiding being eaten and for spatial orientation. It is well known for its ability to use stereopsis for estimating the distance of objects. The neuronal substrate mediating visually driven behaviors, however, is not very well investigated. To provide a basis for future functional studies, we analyzed the anatomical organization of visual neuropils in the brain of the praying mantis Hierodula membranacea and provide supporting evidence from a second species, Rhombodera basalis, with particular focus on the lobula complex (LOX). Neuropils were three‐dimensionally reconstructed from synapsin‐immunostained whole mount brains. The neuropil organization and the pattern of γ‐aminobutyric acid immunostaining of the medulla and LOX were compared between the praying mantis and two related polyneopteran species, the Madeira cockroach and the desert locust. The investigated visual neuropils of the praying mantis are highly structured. Unlike in most insects the LOX of the praying mantis consists of five nested neuropils with at least one neuropil not present in the cockroach or locust. Overall, the mantis LOX is more similar to the LOX of the locust than the more closely related cockroach suggesting that the sensory ecology plays a stronger role than the phylogenetic distance of the three species in structuring this center of visual information processing.
Collapse
Affiliation(s)
- Ronny Rosner
- Institute of Neuroscience, Henry Wellcome Building for Neuroecology, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, United Kingdom
| | - Joss von Hadeln
- Department of Biology, Animal Physiology, Philipps-University, 35032, Marburg, Germany
| | - Tobias Salden
- Department of Biology, Animal Physiology, Philipps-University, 35032, Marburg, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-University, 35032, Marburg, Germany
| |
Collapse
|
295
|
Montagna M, Haug JT, Strada L, Haug C, Felber M, Tintori A. Central nervous system and muscular bundles preserved in a 240 million year old giant bristletail (Archaeognatha: Machilidae). Sci Rep 2017; 7:46016. [PMID: 28387236 PMCID: PMC5384076 DOI: 10.1038/srep46016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 02/28/2017] [Indexed: 11/09/2022] Open
Abstract
Among the incomparably diverse group of insects no cases of central nervous system (CNS) preservation have been so far described in compression fossils. A third of the fossil insects collected from a 240–239 million year old (Ma) level at Monte San Giorgio UNESCO World Heritage (Switzerland-Italy) underwent phosphatization, resulting in the extraordinary preservation of soft tissues. Here we describe Gigamachilis triassicus gen. et sp. nov. (Archaeognatha: Machiloidea: Machilidae) that, with an estimated total length of ~80 millimeters, represents the largest apterygote insect ever recorded. The holotype preserves: (i) components of the CNS represented by four abdominal ganglia, optic lobes with neuropils and compound retina; (ii) muscular bundles. Moreover, G. triassicus, possessing morphological features that prompt its assignment to the extant archaeognathan ingroup Machilidae, places the origin of modern lineages to Middle Triassic. Interestingly, at Monte San Giorgio, in the same stratigraphic unit the modern morphology of G. triassicus co-occurs with the ancient one represented by Dasyleptus triassicus (Archaeognatha: †Monura). Comparing these two types of body organization we provide a new reconstruction of the possible character evolution leading towards modern archaeognathan forms, suggesting the acquisition of novel features in a lineage of apterygote insects during the Permian or the Lower Triassic.
Collapse
Affiliation(s)
- Matteo Montagna
- Dipartimento di Scienze Agrarie e Ambientali - Università degli Studi di Milano, Via Celoria 2, I-20133 Milano, Italy
| | - Joachim T Haug
- Functional Morphology, Department of Biology II and GeoBio-Center, LMU Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
| | - Laura Strada
- Dipartimento di Scienze della Terra "Ardito Desio" - Università degli Studi di Milano, Via Mangiagalli 34, I-20133 Milano, Italy
| | - Carolin Haug
- Functional Morphology, Department of Biology II and GeoBio-Center, LMU Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
| | - Markus Felber
- Consulenze Geologiche e Ambientali SA, Via Comacini 31, CH-6834 Morbio Inferiore, Switzerland
| | - Andrea Tintori
- Dipartimento di Scienze della Terra "Ardito Desio" - Università degli Studi di Milano, Via Mangiagalli 34, I-20133 Milano, Italy
| |
Collapse
|
296
|
Nirazawa T, Fujii T, Seki Y, Namiki S, Kazawa T, Kanzaki R, Ishikawa Y. Morphology and physiology of antennal lobe projection neurons in the hawkmoth Agrius convolvuli. JOURNAL OF INSECT PHYSIOLOGY 2017; 98:214-222. [PMID: 28118991 DOI: 10.1016/j.jinsphys.2017.01.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/13/2017] [Accepted: 01/16/2017] [Indexed: 06/06/2023]
Abstract
The neuronal pathways involved in the processing of sex pheromone information were investigated in the hawkmoth Agrius convolvuli (Lepidoptera: Sphingidae), which uses (E,E)-11,13-hexadecadienal (E11,E13-16:Ald) as the single sex pheromone component. We first clarified the anatomical organization of the antennal lobe of A. convolvuli. Subsequently, central neurons in the antennal lobe that responded to E11,E13-16:Ald were identified. The dendritic processes of these neurons were confined within a specific glomerulus (cumulus) in the antennal lobe. The axons of these neurons projected to the inferior lateral protocerebrum and mushroom body calyx. Although the anatomical organization and morphology of individual neurons in A. convolvuli were similar to other species in the superfamily Bombycoidea, the use of cumulus as the single pathway for sex pheromone information processing was characteristic to this species.
Collapse
Affiliation(s)
- Takuya Nirazawa
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8904, Japan; Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8567, Japan
| | - Takeshi Fujii
- Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8567, Japan.
| | - Yoichi Seki
- Laboratory of Cellular Neurobiology, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Shigehiro Namiki
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8904, Japan
| | - Tomoki Kazawa
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8904, Japan
| | - Ryohei Kanzaki
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8904, Japan
| | - Yukio Ishikawa
- Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8567, Japan
| |
Collapse
|
297
|
Schultzhaus JN, Saleem S, Iftikhar H, Carney GE. The role of the Drosophila lateral horn in olfactory information processing and behavioral response. JOURNAL OF INSECT PHYSIOLOGY 2017; 98:29-37. [PMID: 27871975 DOI: 10.1016/j.jinsphys.2016.11.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 11/16/2016] [Accepted: 11/17/2016] [Indexed: 06/06/2023]
Abstract
Animals must rapidly and accurately process environmental information to produce the correct behavioral responses. Reactions to previously encountered as well as to novel but biologically important stimuli are equally important, and one understudied region in the insect brain plays a role in processing both types of stimuli. The lateral horn is a higher order processing center that mainly processes olfactory information and is linked via olfactory projection neurons to another higher order learning center, the mushroom body. This review focuses on the lateral horn of Drosophila where most functional studies have been performed. We discuss connectivity between the primary olfactory center, the antennal lobe, and the lateral horn and mushroom body. We also present evidence for the lateral horn playing roles in innate behavioral responses by encoding biological valence to novel odor cues and in learned responses to previously encountered odors by modulating neural activity within the mushroom body. We describe how these processes contribute to acceptance or avoidance of appropriate or inappropriate mates and food, as well as the identification of predators. The lateral horn is a sexually dimorphic and plastic region of the brain that modulates other regions of the brain to ensure that insects produce rapid and effective behavioral responses to both novel and learned stimuli, yet multiple gaps exist in our knowledge of this important center. We anticipate that future studies on olfactory processing, learning, and innate behavioral responses will include the lateral horn in their examinations, leading to a more comprehensive understanding of olfactory information relay and resulting behaviors.
Collapse
Affiliation(s)
- Janna N Schultzhaus
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843-3258, United States
| | - Sehresh Saleem
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843-3258, United States
| | - Hina Iftikhar
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843-3258, United States
| | - Ginger E Carney
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843-3258, United States.
| |
Collapse
|
298
|
Polavaram S, Ascoli GA. An ontology-based search engine for digital reconstructions of neuronal morphology. Brain Inform 2017; 4:123-134. [PMID: 28337675 PMCID: PMC5413594 DOI: 10.1007/s40708-017-0062-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/13/2017] [Indexed: 11/27/2022] Open
Abstract
Neuronal morphology is extremely diverse across and within animal species, developmental stages, brain regions, and cell types. This diversity is functionally important because neuronal structure strongly affects synaptic integration, spiking dynamics, and network connectivity. Digital reconstructions of axonal and dendritic arbors are thus essential to quantify and model information processing in the nervous system. NeuroMorpho.Org is an established repository containing tens of thousands of digitally reconstructed neurons shared by several hundred laboratories worldwide. Each neuron is annotated with specific metadata based on the published references and additional details provided by data owners. The number of represented metadata concepts has grown over the years in parallel with the increase of available data. Until now, however, the lack of standardized terminologies and of an adequately structured metadata schema limited the effectiveness of user searches. Here we present a new organization of NeuroMorpho.Org metadata grounded on a set of interconnected hierarchies focusing on the main dimensions of animal species, anatomical regions, and cell types. We have comprehensively mapped each metadata term in NeuroMorpho.Org to this formal ontology, explicitly resolving all ambiguities caused by synonymy and homonymy. Leveraging this consistent framework, we introduce OntoSearch, a powerful functionality that seamlessly enables retrieval of morphological data based on expert knowledge and logical inferences through an intuitive string-based user interface with auto-complete capability. In addition to returning the data directly matching the search criteria, OntoSearch also identifies a pool of possible hits by taking into consideration incomplete metadata annotation.
Collapse
Affiliation(s)
- Sridevi Polavaram
- Center for Neural Informatics, Structures and Plasticity, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA
| | - Giorgio A Ascoli
- Center for Neural Informatics, Structures and Plasticity, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA.
| |
Collapse
|
299
|
Immonen EV, Dacke M, Heinze S, El Jundi B. Anatomical organization of the brain of a diurnal and a nocturnal dung beetle. J Comp Neurol 2017; 525:1879-1908. [PMID: 28074466 DOI: 10.1002/cne.24169] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/14/2016] [Accepted: 12/21/2016] [Indexed: 12/25/2022]
Abstract
To avoid the fierce competition for food, South African ball-rolling dung beetles carve a piece of dung off a dung-pile, shape it into a ball and roll it away along a straight line path. For this unidirectional exit from the busy dung pile, at night and day, the beetles use a wide repertoire of celestial compass cues. This robust and relatively easily measurable orientation behavior has made ball-rolling dung beetles an attractive model organism for the study of the neuroethology behind insect orientation and sensory ecology. Although there is already some knowledge emerging concerning how celestial cues are processed in the dung beetle brain, little is known about its general neural layout. Mapping the neuropils of the dung beetle brain is thus a prerequisite to understand the neuronal network that underlies celestial compass orientation. Here, we describe and compare the brains of a day-active and a night-active dung beetle species based on immunostainings against synapsin and serotonin. We also provide 3D reconstructions for all brain areas and many of the fiber bundles in the brain of the day-active dung beetle. Comparison of neuropil structures between the two dung beetle species revealed differences that reflect adaptations to different light conditions. Altogether, our results provide a reference framework for future studies on the neuroethology of insects in general and dung beetles in particular.
Collapse
Affiliation(s)
- Esa-Ville Immonen
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland.,Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Marie Dacke
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| | - Stanley Heinze
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| | - Basil El Jundi
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| |
Collapse
|
300
|
Schwarz O, Bohra AA, Liu X, Reichert H, VijayRaghavan K, Pielage J. Motor control of Drosophila feeding behavior. eLife 2017; 6:e19892. [PMID: 28211791 PMCID: PMC5315463 DOI: 10.7554/elife.19892] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 02/02/2017] [Indexed: 12/01/2022] Open
Abstract
The precise coordination of body parts is essential for survival and behavior of higher organisms. While progress has been made towards the identification of central mechanisms coordinating limb movement, only limited knowledge exists regarding the generation and execution of sequential motor action patterns at the level of individual motoneurons. Here we use Drosophila proboscis extension as a model system for a reaching-like behavior. We first provide a neuroanatomical description of the motoneurons and muscles contributing to proboscis motion. Using genetic targeting in combination with artificial activation and silencing assays we identify the individual motoneurons controlling the five major sequential steps of proboscis extension and retraction. Activity-manipulations during naturally evoked proboscis extension show that orchestration of serial motoneuron activation does not rely on feed-forward mechanisms. Our data support a model in which central command circuits recruit individual motoneurons to generate task-specific proboscis extension sequences.
Collapse
Affiliation(s)
- Olivia Schwarz
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Biozentrum University of Basel, Basel, Switzerland
- Division of Zoology and Neurobiology, Technical University Kaiserslautern, Kaiserslautern, Germany
| | - Ali Asgar Bohra
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Xinyu Liu
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Biozentrum University of Basel, Basel, Switzerland
| | | | | | - Jan Pielage
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Biozentrum University of Basel, Basel, Switzerland
- Division of Zoology and Neurobiology, Technical University Kaiserslautern, Kaiserslautern, Germany
| |
Collapse
|