scholarly journals Odor processing in the cockroach antennal lobe—the network components

2021 ◽  
Vol 383 (1) ◽  
pp. 59-73
Author(s):  
Debora Fuscà ◽  
Peter Kloppenburg
Keyword(s):  
Antennal Lobe ◽  
Periplaneta Americana ◽  
Experimental System ◽  
Projection Neurons ◽  
Odor Processing ◽  
Local Interneurons ◽  
Physiological Properties ◽  
Functional Equivalent ◽  
The Central Nervous System ◽  
Physiological Tasks

AbstractHighly interconnected neural networks perform olfactory signal processing in the central nervous system. In insects, the first synaptic processing of the olfactory input from the antennae occurs in the antennal lobe, the functional equivalent of the olfactory bulb in vertebrates. Key components of the olfactory network in the antennal lobe are two main types of neurons: the local interneurons and the projection (output) neurons. Both neuron types have different physiological tasks during olfactory processing, which accordingly require specialized functional phenotypes. This review gives an overview of important cell type-specific functional properties of the different types of projection neurons and local interneurons in the antennal lobe of the cockroach Periplaneta americana, which is an experimental system that has elucidated many important biophysical and cellular bases of intrinsic physiological properties of these neurons.

scholarly journals Task-specific roles of local interneurons for inter- and intraglomerular signaling in the insect antennal lobe

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Debora Fusca ◽  
Peter Kloppenburg
Keyword(s):  
Antennal Lobe ◽  
Periplaneta Americana ◽  
Morphological Properties ◽  
Primary Role ◽  
Tuning Curves ◽  
Complex Interactions ◽  
Local Interneurons ◽  
Whole Cell Patch Clamp ◽  
Functional Analog ◽  
Cell Type Specific

Local interneurons (LNs) mediate complex interactions within the antennal lobe, the primary olfactory system of insects, and the functional analog of the vertebrate olfactory bulb. In the cockroach Periplaneta americana, as in other insects, several types of LNs with distinctive physiological and morphological properties can be defined. Here, we combined whole-cell patch-clamp recordings and Ca2+ imaging of individual LNs to analyze the role of spiking and nonspiking LNs in inter- and intraglomerular signaling during olfactory information processing. Spiking GABAergic LNs reacted to odorant stimulation with a uniform rise in [Ca2+]i in the ramifications of all innervated glomeruli. In contrast, in nonspiking LNs, glomerular Ca2+ signals were odorant specific and varied between glomeruli, resulting in distinct, glomerulus-specific tuning curves. The cell type-specific differences in Ca2+ dynamics support the idea that spiking LNs play a primary role in interglomerular signaling, while they assign nonspiking LNs an essential role in intraglomerular signaling.

scholarly journals Task-specific roles of local interneurons for inter -and intraglomerular signaling in the insect antennal lobe

2020 ◽  
Author(s):  
Debora Fusca ◽  
Peter Kloppenburg
Keyword(s):  
Antennal Lobe ◽  
Periplaneta Americana ◽  
Morphological Properties ◽  
Primary Role ◽  
Tuning Curves ◽  
Complex Interactions ◽  
Local Interneurons ◽  
Whole Cell Patch Clamp ◽  
Functional Analog ◽  
Cell Type Specific

AbstractLocal interneurons (LNs) mediate complex interactions within the antennal lobe, the primary olfactory system of insects, and the functional analog of the vertebrate olfactory bulb. In the cockroach Periplaneta Americana, as in other insects, several types of LNs with distinctive physiological and morphological properties can be defined. Here, we combined whole-cell patch clamp recordings and Ca2+ imaging of individual LNs to analyze the role of spiking and nonspiking LNs in inter- and intraglomerular signaling during olfactory information processing. Spiking GABAergic LNs reacted to odorant stimulation with a uniform rise in [Ca2+]i in the ramifications of all innervated glomeruli. In contrast, in nonspiking LNs, glomerular Ca2+ signals were odorant specific and varied between glomeruli, resulting in distinct, glomerulus-specific tuning curves. The cell type-specific differences in Ca2+ dynamics support the idea that spiking LNs play a primary role in interglomerular signaling, while they assign nonspiking LNs an essential role in intraglomerular signaling.

scholarly journals Local interneurons and projection neurons in the antennal lobe from a spiking point of view

2013 ◽  
Vol 110 (10) ◽  
pp. 2465-2474 ◽  
Author(s):  
Anneke Meyer ◽  
C. Giovanni Galizia ◽  
Martin Paul Nawrot
Keyword(s):  
Antennal Lobe ◽  
Essential Feature ◽  
Point Of View ◽  
Local Network ◽  
Projection Neurons ◽  
Receptor Repertoire ◽  
Local Interneurons ◽  
Spatio Temporal ◽  
Characteristic Features

Local computation in microcircuits is an essential feature of distributed information processing in vertebrate and invertebrate brains. The insect antennal lobe represents a spatially confined local network that processes high-dimensional and redundant peripheral input to compute an efficient odor code. Social insects can rely on a particularly rich olfactory receptor repertoire, and they exhibit complex odor-guided behaviors. This corresponds with a high anatomical complexity of their antennal lobe network. In the honeybee, a large number of glomeruli that receive sensory input are interconnected by a dense network of local interneurons (LNs). Uniglomerular projection neurons (PNs) integrate sensory and recurrent local network input into an efficient spatio-temporal odor code. To investigate the specific computational roles of LNs and PNs, we measured several features of sub- and suprathreshold single-cell responses to in vivo odor stimulation. Using a semisupervised cluster analysis, we identified a combination of five characteristic features as sufficient to separate LNs and PNs from each other, independent of the applied odor-stimuli. The two clusters differed significantly in all these five features. PNs showed a higher spontaneous subthreshold activation, assumed higher peak response rates and a more regular spiking pattern. LNs reacted considerably faster to the onset of a stimulus, and their responses were more reliable across stimulus repetitions. We discuss possible mechanisms that can explain our results, and we interpret cell-type-specific characteristics with respect to their functional relevance.

Direct and glia-mediated effects of GABA on development of central olfactory neurons

2011 ◽  
Vol 7 (2-4) ◽  
pp. 143-161
Author(s):  
Heather S. Mallory ◽  
Nicholas J. Gibson ◽  
Jon H. Hayashi ◽  
Alan J. Nighorn ◽  
Lynne A. Oland
Keyword(s):  
Glial Cells ◽  
Antennal Lobe ◽  
Neuronal Morphology ◽  
Projection Neurons ◽  
Olfactory Pathway ◽  
Mediated Effects ◽  
Local Interneurons ◽  
Outward Currents ◽  
Olfactory Glomeruli

Previously studied for its role in processing olfactory information in the antennal lobe, GABA also may shape development of the olfactory pathway, acting either through or on glial cells. Early in development, the dendrites of GABAergic neurons extend to the glial border that surrounds the nascent olfactory lobe neuropil. These neuropil glia express both GABAA and GABAB receptors, about half of the glia in acute cultures responded to GABA with small outward currents, and about a third responded with small transient increases in intracellular calcium. The neuronal classes that express GABA in vivo, the local interneurons and a subset of projection neurons, also do so in culture. Exposure to GABA in culture increased the size and complexity of local interneurons, but had no effect on glial morphology. The presence of glia alone did not affect neuronal morphology, but in the presence of both glia and GABA, the growth-enhancing effects of GABA on cultured antennal lobe neurons were eliminated. Contact between the glial cells and the neurons was not necessary. Operating in vivo, these antagonistic effects, one direct and one glia mediated, could help to sculpt the densely branched, tufted arbors that are characteristic of neurons innervating olfactory glomeruli.

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