Primary sensory neurons containing command neuron peptide constitute a morphologically distinct class of sensory neurons in the terrestrial snail

Vinarskaya

Zuzina

et al. 2016

Sci Rep

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We analyzed changes in the activity of individually identifiable neurons involved in the networks underlying feeding and withdrawal behaviors in snails before, during, and after aversive learning in vitro. Responses to food in the “reinforcing” serotonergic neurons involved in withdrawal changed significantly after training, implying that these serotonergic cells participate in the reactivation of memory and are involved in the reconsolidation process. In behavioral experiments it was shown that impairment of the functioning of the serotonergic system with the selective neurotoxin 5,7-DiHT did not change the memory, when tested once, but resulted in a complete extinction of the contextual memory after repeated reactivation of memory. Conversely, the cued memory to a specific type of food was significantly reduced but still present. Thus, we conclude that it is only for the context memory, that participation of the “reinforcing” serotonergic neurons in memory retrieval may be the gate condition for the choice between extinction/reconsolidation.

Section: Resultsmentioning

confidence: 99%

Impairment of the serotonergic neurons underlying reinforcement elicits extinction of the repeatedly reactivated context memory

Vinarskaya

Zuzina

et al. 2016

Sci Rep

Self Cite

“…In Helix, the tentacle CNP-IR receptors seem to be the mechanoreceptors (Ierusalimsky and Balaban 2007b). Fibers of IR neurons in the pleural ganglia spread to the areas occupied by mechanosensory cells, which suggests a possible interaction.…”

Section: Morphology and Functions Of The Cnpl-ir Neurons In Various Imentioning

confidence: 99%

“…Previously, only the data on the primary sensory cells in the tentacles have been published (Ierusalimsky and Balaban 2007b).…”

Section: Pulmonata: Helix Lucorummentioning

confidence: 99%

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Family of CNP neuropeptides: common morphology in various invertebrates

Ierusalimsky

2011

Cell Tissue Res

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Neuropeptides expressed in the command neurons for withdrawal behavior were originally detected in the the central nervous system (CNS) of the terrestrial snail Helix (command neurons peptides, CNP). The family of CNP-like neuropeptides bears a C-terminal signature sequence Tyr-Pro-Arg-X. Using antisera against two of them, we have studied the CNS of various invertebrates belonging to the phyla of mollusks, annelids and insects. The immunoreactive neurons were detected in all studied species. Stained neurons were either interneurons projecting along the CNS ganglia chain, or sensory neurons, or neurohormonal cells. Beyond common morphological features, the immunoreactive cells had another similarity: the level of CNP expression depended on the functional state of the animal. Thus, the homologous neuropeptides in evolutionary distant invertebrate species possess some common morphological and functional features.

“…A small part of the sensory cells population sends their axons directly to the cerebral ganglion (Chase and Tolloczko, 1986). Thus, there are three parallel pathways from the sensory pad primary neurons used in olfactory processing: to glomeruli, to interneurons of a tentacular ganglion, and direct projections to the cerebral ganglia (Chase and Tolloczko, 1993; Ierusalimsky and Balaban, 2007). The PC lobe is a division of the cerebral ganglion unique to terrestrial slugs and snails that is specialized for the processing (third stage) of olfactory information (Ratte and Chase, 1997).…”

Section: Introductionmentioning

confidence: 99%

Changes in frequency of spontaneous oscillations in procerebrum correlate to behavioural choice in terrestrial snails.

Samarova

2009

Front. Cell. Neurosci.

The aim of our study was to understand functional significance of spontaneous oscillations of local field potential in the olfactory brain lobe of terrestrial snail, the procerebrum (PC). We compared changes in frequency of oscillations in semi-intact preparations from snails trained to percept the same conditioned odor as positive (associated with food reinforcement) or negative (associated with noxious reinforcement). In vivo recordings in freely behaving naïve snails showed a significant decrease of spontaneous PC oscillations frequency during a stage of tentacle withdrawal to odor presentation. In in vitro preparations from naïve snails, a similar decrease in frequency of the PC oscillations to odor presentation was observed. Changes in frequency of the oscillations to cineole presentations in the “aversive” group of snails (demonstrating withdrawal) were much more pronounced than in naïve snails. No significant difference in responses to 5% and 20% cineole was noted. Changes in the spontaneous oscillations frequency in the snails trained to respond with positive reaction (approach) to cineole depended on the concentration of the applied odor, and these responses were qualitatively similar to responses of other groups during the first 10 s of responses to odor, but significantly different (increase in PC oscillations frequency) from the responses of the aversively trained and naïve snails in the interval 11–30 s, which corresponds to the end of the tentacle withdrawal and timing of decision making (approach or escape) in the free behaving snails. Obtained results suggest that frequency of the PC lobe spontaneous oscillations correlate to the choice of behavior in snails: withdrawal (decrease in frequency) or approach (increase in frequency) to the source of odor.