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Hensgen R, Göthe J, Jahn S, Hümmert S, Schneider KL, Takahashi N, Pegel U, Gotthardt S, Homberg U. Organization and neural connections of the lateral complex in the brain of the desert locust. J Comp Neurol 2021; 529:3533-3560. [PMID: 34216020 DOI: 10.1002/cne.25209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 11/08/2022]
Abstract
The lateral complexes (LXs) are bilaterally paired neuropils in the insect brain that mediate communication between the central complex (CX), a brain center controlling spatial orientation, various sensory processing areas, and thoracic motor centers that execute locomotion. The LX of the desert locust consists of the lateral accessory lobe (LAL), and the medial and lateral bulb. We have analyzed the anatomical organization and the neuronal connections of the LX in the locust, to provide a basis for future functional studies. Reanalyzing the morphology of neurons connecting the CX and the LX revealed likely feedback loops in the sky compass network of the CX via connections in the gall of the LAL and a newly identified neuropil termed ovoid body. In addition, we characterized 16 different types of neuron that connect the LAL with other areas in the brain. Eight types of neuron provide information flow between both LALs, five types are LAL input neurons, and three types are LAL output neurons. Among these are neurons providing input from sensory brain areas such as the lobula and antennal neuropils. Brain regions most often targeted by LAL neurons are the posterior slope, the wedge, and the crepine. Two descending neurons with dendrites in the LAL were identified. Our data support and complement existing knowledge about how the LAL is embedded in the neuronal network involved in processing of sensory information and generation of appropriate behavioral output for goal-directed locomotion.
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Affiliation(s)
- Ronja Hensgen
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Jonas Göthe
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Stefanie Jahn
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Sophie Hümmert
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Kim Lucia Schneider
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Naomi Takahashi
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Uta Pegel
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Sascha Gotthardt
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
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Homberg U, Hensgen R, Rieber E, Seyfarth J, Kern M, Dippel S, Dircksen H, Spänig L, Kina YP. Orcokinin in the central complex of the locust Schistocerca gregaria: Identification of immunostained neurons and colocalization with other neuroactive substances. J Comp Neurol 2020; 529:1876-1894. [PMID: 33128250 DOI: 10.1002/cne.25062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/22/2020] [Accepted: 10/22/2020] [Indexed: 12/20/2022]
Abstract
The central complex is a group of highly interconnected neuropils in the insect brain. It is involved in the control of spatial orientation, based on external compass cues and various internal needs. The functional and neurochemical organization of the central complex has been studied in detail in the desert locust Schistocerca gregaria. In addition to classical neurotransmitters, immunocytochemistry has provided evidence for a major contribution of neuropeptides to neural signaling within the central complex. To complement these data, we have identified all orcokinin-immunoreactive neurons in the locust central complex and associated brain areas. About 50 bilateral pairs of neurons innervating all substructures of the central complex exhibit orcokinin immunoreactivity. Among these were about 20 columnar neurons, 33 bilateral pairs of tangential neurons of the central body, and seven pairs of tangential neurons of the protocerebral bridge. In silico transcript analysis suggests the presence of eight different orcokinin-A type peptides in the desert locust. Double label experiments showed that all orcokinin-immunostained tangential neurons of the lateral accessory lobe cluster were also immunoreactive for GABA and the GABA-synthesizing enzyme glutamic acid decarboxylase. Two types of tangential neurons of the upper division of the central body were, furthermore, also labeled with an antiserum against Dip-allatostatin I. No colocalization was found with serotonin immunostaining. The data provide additional insights into the neurochemical organization of the locust central complex and suggest that orcokinin-peptides of the orcokinin-A gene act as neuroactive substances at all stages of signal processing in this brain area.
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Affiliation(s)
- Uwe Homberg
- Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Ronja Hensgen
- Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Evelyn Rieber
- Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany.,Behavioral Physiology and Sociobiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jutta Seyfarth
- Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Martina Kern
- Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Stefan Dippel
- Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | | | - Lisa Spänig
- Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Yelda Pakize Kina
- Department of Biology, Animal Physiology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
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