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Swart CC, Wattenberger A, Hackett A, Isaman D. Lifelong neurogenesis in the cerebral ganglion of the Chinese mud snail, Cipangopaludina chinensis. Brain Behav 2017; 7:e00652. [PMID: 28413703 PMCID: PMC5390835 DOI: 10.1002/brb3.652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/06/2016] [Accepted: 12/18/2016] [Indexed: 02/02/2023] Open
Abstract
INTRODUCTION A small group of Gastropods possessing giant neurons have long been used to study a wide variety of fundamental neurophysiological phenomena. However, the majority of gastropods do not have large neurons but instead have large numbers of small neurons and remain largely unstudied. We explored neuron size and rate of increase in neuron numbers in the Chinese mud snail, Cipangopaludina chinensis. METHODS Using histological sections and whole mounts of the cerebral ganglia, we collected cross-sectional data on neuron number and size across the lifespan of this animal. Neurogenesis was verified using Click-it EdU staining. RESULTS We found that total neuron number in the cerebral ganglia increases throughout the lifespan of this species at a constant rate. New neurons arise primarily near the nerve roots. Females live longer (up to 7 years) than males (up to 5 years) and thus achieve larger numbers of neurons in the cerebral ganglion. Neuron size is consistently small (<10 μm) in the cerebral ganglia at all ages, however, cells in the posterior section of the cerebral ganglia are modestly but significantly larger than cells at the anterior. CONCLUSIONS These features suggest that C. chinensis and similar species of Caenogastropoda are good candidates for studying gastropod neurogenesis, senescence, and sex differences in the nervous system.
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Serfőző Z, Nacsa K, Veréb Z, Battonyai I, Hegedűs C, Balogh C, Elekes K. Nitric oxide-coupled signaling in odor elicited molecular events in the olfactory center of the terrestrial snail, Helix pomatia. Cell Signal 2016; 30:67-81. [PMID: 27884734 DOI: 10.1016/j.cellsig.2016.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/15/2016] [Accepted: 11/18/2016] [Indexed: 12/22/2022]
Abstract
Olfaction, a chemosensory modality, plays a pivotal role in the orientation and behavior of invertebrates. The central olfactory processing unit in terrestrial stylomatophoran snails is the procerebrum, which contains NO synthesizing interneurons, whose oscillatory currents are believed to be the base of odor evoked memory formation. Nevertheless, in this model the up- and downstream events of molecular cascades that trigger and follow NO release, respectively, have not been studied. Immunocytochemistry and flow cytometry studies performed on procerebral neural perikarya isolated from the snail Helix pomatia revealed cell populations with discrete DAF-2 fluorescence, indicating the release of different amounts of NO. Glutamate increased the intensity of DAF-2 fluorescence, and the number of DAF-2 positive non-bursting interneurons, through a mechanism likely to involve an NMDA-like receptor. Similarly to glutamate, NO activation induced an increase in intracellular cGMP levels through activation of soluble guanylyl cyclase. Immunohistochemical localization of proteins possessing the phosphorylated target sequence of AGC family kinases (RXXS/T-P), among them protein kinase A (RRXS/T-P), showed striking similarities to the distribution of NOS/cGMP. Activators of cyclic nucleotide synthesis increased the AGC-kinase-dependent phosphorylation of discrete proteins with 28, 45, and 55kDamw. Importantly, exposure of snails to an attractive odorant induced hyperphosphorylation of the 28kDa protein, and increased levels of cGMP synthesis. Protein S-nitrosylation and intercellular activation of protein kinase G were also suggested as alternative components of NO signaling in the snail procerebrum. The present results from Helix pomatia indicate an important role for procerebrum NO/cGMP/PKA signaling pathways in the regulation of olfactory (food-finding) behavior.
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Affiliation(s)
- Zoltán Serfőző
- MTA Centre for Ecological Research, Balaton Limnological Institute, Tihany, Hungary.
| | - Kálmán Nacsa
- MTA Centre for Ecological Research, Balaton Limnological Institute, Tihany, Hungary
| | - Zoltán Veréb
- Institute of Biochemistry and Molecular Biology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
| | - Izabella Battonyai
- MTA Centre for Ecological Research, Balaton Limnological Institute, Tihany, Hungary
| | - Csaba Hegedűs
- Institute of Medical Chemistry, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
| | - Csilla Balogh
- MTA Centre for Ecological Research, Balaton Limnological Institute, Tihany, Hungary
| | - Károly Elekes
- MTA Centre for Ecological Research, Balaton Limnological Institute, Tihany, Hungary
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Voltage-gated membrane currents in neurons involved in odor information processing in snail procerebrum. Brain Struct Funct 2013; 219:673-82. [DOI: 10.1007/s00429-013-0526-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 02/08/2013] [Indexed: 10/27/2022]
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Kobayashi S, Ito E. GABAergic effects on the slow oscillatory neural activities in the procerebrum of Limax valentianus. Short communication. ACTA BIOLOGICA HUNGARICA 2012; 63 Suppl 2:91-5. [PMID: 22776480 DOI: 10.1556/abiol.63.2012.suppl.2.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We examined GABAergic modulation on "slow" oscillation (<1.0 Hz) of the procerebrum in the terrestrial mollusk, Limax valentianus. Short application of GABA-receptor agonists slightly increased the frequency of a periodic oscillation in the procerebrum, whereas persistent application decreased it. GABA-receptor antagonists decreased the oscillatory frequency. The GABA-like immunoreactivities were found in the neuropil and the cell body layers of the procerebrum. Because GABAergic inhibition is known to be essential for the generation of "fast" synchronous neuronal oscillation in the CNSs in othre many animals, our present findings are first evidence suggesting that GABA modulates 'slow' oscillation in the CNS.
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Affiliation(s)
- S Kobayashi
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.
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Kobayashi S, Matsuo R, Sadamoto H, Watanabe S, Ito E. Excitatory effects of GABA on procerebrum neurons in a slug. J Neurophysiol 2012; 108:989-98. [DOI: 10.1152/jn.01137.2010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Classical neurotransmitters, such as glutamate and γ-aminobutyric acid (GABA), often have different actions on invertebrate neurons from those reported for vertebrate neurons. In the terrestrial mollusk Limax, glutamate was found to function as an inhibitory transmitter in the procerebrum (PC), but it has not yet been clarified how GABA acts in the PC. We thus examined what effects GABA exerts on PC neurons in the present study. For this purpose, we first applied GABA to isolated PC preparations and recorded postsynaptic currents and potentials in PC neurons. The GABA application reduced the amplitude of inhibitory postsynaptic currents and depolarization-induced outward currents recorded in nonbursting neurons and increased the number of spontaneous spikes of nonbursting neurons. However, direct GABA-induced currents were not observed in either bursting or nonbursting neurons. These results suggest a potential direct effect of GABA on outward currents resulting in enhanced excitability of PC neurons. Next, we measured the change in [Ca2+]i in cultured PC neurons by application of GABA. The GABA application increased spontaneous Ca2+ events in cultured neurons. These Ca2+ events were ascribable to the influx of extracellular Ca2+. We then confirmed the presence of GABA and GABA receptors in the PC. The GABA-like immunoreactivity was observed in the neuropil layers of the PC, and the mRNAs for both GABAA and GABAB receptors were expressed in the PC. In particular, GABAB receptor mRNA, rather than GABAA, was found to be more abundantly expressed in the PC. These results suggest that GABA functions as an excitatory modulator for PC neurons via mainly GABAB receptors.
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Affiliation(s)
- Suguru Kobayashi
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa, Japan; and
| | - Ryota Matsuo
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa, Japan; and
| | - Hisayo Sadamoto
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa, Japan; and
| | - Satoshi Watanabe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Etsuro Ito
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa, Japan; and
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Organization of the procerebrum in terrestrial pulmonates (Helix, Limax) reconsidered: cell mass layer synaptology and its serotonergic input system. Brain Struct Funct 2012; 218:477-90. [DOI: 10.1007/s00429-012-0409-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 03/16/2012] [Indexed: 10/28/2022]
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Comparative neuroanatomy of Caudofoveata, Solenogastres, Polyplacophora, and Scaphopoda (Mollusca) and its phylogenetic implications. ZOOMORPHOLOGY 2012. [DOI: 10.1007/s00435-012-0150-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Matsuo R, Kobayashi S, Yamagishi M, Ito E. Two pairs of tentacles and a pair of procerebra: optimized functions and redundant structures in the sensory and central organs involved in olfactory learning of terrestrial pulmonates. J Exp Biol 2011; 214:879-86. [DOI: 10.1242/jeb.024562] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Terrestrial pulmonates can learn olfactory-aversion tasks and retain them in their long-term memory. To elucidate the cellular mechanisms underlying learning and memory, researchers have focused on both the peripheral and central components of olfaction: two pairs of tentacles (the superior and inferior tentacles) and a pair of procerebra, respectively. Data from tentacle-amputation experiments showed that either pair of tentacles is sufficient for olfactory learning. Results of procerebrum lesion experiments showed that the procerebra are necessary for olfactory learning but that either one of the two procerebra, rather than both, is used for each olfactory learning event. Together, these data suggest that there is a redundancy in the structures of terrestrial pulmonates necessary for olfactory learning. In our commentary we exemplify and discuss functional optimization and structural redundancy in the sensory and central organs involved in olfactory learning and memory in terrestrial pulmonates.
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Affiliation(s)
- Ryota Matsuo
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido, Sanuki 769-2193, Japan
| | - Suguru Kobayashi
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido, Sanuki 769-2193, Japan
| | - Miki Yamagishi
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido, Sanuki 769-2193, Japan
| | - Etsuro Ito
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido, Sanuki 769-2193, Japan
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Sekiguchi T, Furudate H, Kimura T. Internal representation and memory formation of odor preference based on oscillatory activities in a terrestrial slug. Learn Mem 2010; 17:372-80. [DOI: 10.1101/lm.1867110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Samarova E, Balaban P. Changes in frequency of spontaneous oscillations in procerebrum correlate to behavioural choice in terrestrial snails. Front Cell Neurosci 2009; 3:8. [PMID: 19753329 PMCID: PMC2742667 DOI: 10.3389/neuro.03.008.2009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Accepted: 07/27/2009] [Indexed: 11/13/2022] Open
Abstract
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.
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Affiliation(s)
- Elena Samarova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science Moscow, Russia
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Watanabe S, Kirino Y, Gelperin A. Neural and molecular mechanisms of microcognition in Limax. Learn Mem 2008; 15:633-42. [DOI: 10.1101/lm920908] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Ierusalimsky VN, Balaban PM. Primary sensory neurons containing command neuron peptide constitute a morphologically distinct class of sensory neurons in the terrestrial snail. Cell Tissue Res 2007; 330:169-77. [PMID: 17605049 DOI: 10.1007/s00441-007-0447-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Accepted: 05/25/2007] [Indexed: 10/23/2022]
Abstract
In the central nervous system of the terrestrial snail Helix, the gene HCS2, which encodes several neuropeptides of the CNP (command neuron peptide) family, is mostly expressed in cells related to withdrawal behavior. In the present work, we demonstrate that a small percentage (0.1%) of the sensory cells, located in the sensory pad and in the surrounding epithelial region ("collar") of the anterior and posterior tentacles, is immunoreactive to antisera raised against the neuropeptides CNP2 and CNP4, encoded by the HCS2 gene. No CNP-like-immunoreactive neurons have been detected among the tentacular ganglionic interneurons. The CNP-like-immunoreactive fiber bundles enter the cerebral ganglia within the nerves of the tentacles (tentacular nerve and medial lip nerve) and innervate the metacerebral lobe, viz., the integrative brain region well-known as the target area for many cerebral ganglia nerves. The procerebral lobe, which is involved in the processing of olfactory information, is not CNP-immunoreactive. Our data suggest that the sensory cells, which contain the CNP neuropeptides, belong to a class of sensory neurons with a specific function, presumably involved in the withdrawal behavior of the snail.
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Affiliation(s)
- Victor N Ierusalimsky
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.
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Nikitin ES, Zakharov IS, Samarova EI, Kemenes G, Balaban PM. Fine tuning of olfactory orientation behaviour by the interaction of oscillatory and single neuronal activity. Eur J Neurosci 2006; 22:2833-44. [PMID: 16324118 DOI: 10.1111/j.1460-9568.2005.04480.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We used a simple sensory and motor system to investigate the neuronal mechanisms of olfactory orientation behaviour. The main olfactory organs of terrestrial molluscs, the experimental animals used in this work, are located on the tips of their tentacles, which display complex movements when they explore a new environment. By reconstructing the trajectory of the tentacle tip ('nose') movements in three dimensions in freely moving snails, we showed that the protracted tentacles performed continuous scanning, both spontaneously and in response to odours. Odour applications elicited a brief startle-like quiver of the tentacle in a concentration-independent manner as well as a concentration-dependent contraction. Previous work showed that activation of an identified cerebral motoneuron, MtC3, produces tentacle contraction. Here we showed that in semi-intact preparations, MtC3 responded to odours in a concentration-dependent manner, similar to the tentacle contraction response to the same odours in intact animals. This observation suggests that MtC3 is involved in the central control of the scanning area by regulating the tentacle length. Using voltage-sensitive dyes and imaging, we demonstrated that during the hyperpolarizing phases of oscillations in the procerebral lobe, the main olfactory centre of the CNS of terrestrial molluscs, MtC3 spike frequency significantly decreased. We also showed that direct activation of the procerebral lobe resulted in the phasic inhibition of MtC3. This is therefore an example of an olfactory system in which the interaction of oscillatory and single neuronal activity plays an important role in the fine tuning of orientation behaviour to suit the particular odour environment.
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Affiliation(s)
- Evgeny S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology, 5 A Butlerova Str. Moscow 117485, Russia.
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Nikitin ES, Balaban PM. Optical recording of responses to odor in olfactory structures of the nervous system in the terrestrial mollusk Helix. NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 2001; 31:21-30. [PMID: 11265810 DOI: 10.1023/a:1026666012225] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Electrophysiological methods and optical methods based on the use of potential-sensitive dyes were used to record stable rhythmic oscillations of local potentials in the olfactory structure (procerebrum) of the pulmonate mollusk Helix: these oscillations were generally similar to those previously observed in slugs. Odor had the effect of transiently altering rhythmic oscillations to generate an individual pattern. This is the first study describing the recording of procerebrum potentials evoked by presentation of odor, with mapping of the areas of propagation of these potentials relative to the areas of propagation of rhythmic oscillations. The boundary of the propagation of the evoked potential was essentially similar to the projection of the neuropil, and rhythmic oscillations were recorded in the projection layer of procerebrum cell bodies. Evoked potential waves appeared in areas corresponding to the site at which the olfactory nerve enters the cerebral ganglion (of which the procerebrum forms a part) and were propagated in the procerebrum neuropil towards the cell body layer. Evoked potentials did not provoke out-of-phase waves of rhythmic oscillations.
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Affiliation(s)
- E S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow
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Nikitin ES, Balaban PM. Optical recording of odor-evoked responses in the olfactory brain of the naïve and aversively trained terrestrial snails. Learn Mem 2000; 7:422-32. [PMID: 11112801 PMCID: PMC311347 DOI: 10.1101/lm.32500] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Regular spontaneous oscillations were recorded both electro- and optophysiologically using a voltage-sensitive absorption dye in the olfactory part of the brain (procerebral lobe of the cerebral ganglia) of the gastropod mollusk Helix lucorum. Odor application caused transient changes in procerebral oscillations, and an odor-evoked potential was recorded in the procerebrum (PC). The wave of evoked potential originated near the place of olfactory nerve entrance into the PC and propagated via the procerebral neuropile toward the cell body layer. The spread of the odor-evoked potential corresponded roughly to the neuropile area, whereas the spontaneous oscillations were recorded in the cell body layer of the PC and were not observed in the neuropile. Evoked potential did not produce additional events intercalated into the ongoing spontaneous oscillations. Changes in parameters of spontaneous oscillations to the repeated presentations of the same odor were variable. To estimate the role of spontaneous oscillations in odor encoding, we trained the snail to avoid cineole, using paired presentations of cineole and electric shock. Elaboration of conditioned aversion to cineole applications resulted in distinct pairing-specific changes in behavior of the snails and procerebral activity. Responses to odor (cineole) applications were not different in amplitude or frequency of spontaneous oscillations in control and trained snails, whereas ratio of amplitudes of the same oscillation wave in proximal and distal regions of the procerebrum was significantly different in control and aversively trained snails, reflecting changes in neural firing in certain areas of the olfactory lobe.
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Affiliation(s)
- E S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology RAS, Moscow 117865, Russia
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Schütt A, Bullock TH, Başar E. Odor input generates approximately 1.5 Hz and approximately 3 Hz spectral peaks in the helix pedal ganglion. Brain Res 2000; 879:73-87. [PMID: 11011008 DOI: 10.1016/s0006-8993(00)02736-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In 1999 we reported that odorants evoke in the Helix pedal ganglion (PG) activity patterns which are largely odorant-specific and related to the nature of odor and its behavioral output. Notably, some activities (for example, approximately 1.5 and approximately 3 Hz), nonspecific to odorants, were consistently evoked in PG. The present contribution goes farther in a deeper survey of the intrinsic and odorant-evoked activities of PG with special weight on the nonspecific fluctuations. We address the following questions. (i) What are the features of the activities? (ii) Are they comparable to the activities found in the motor systems of the other invertebrates? (iii) To what functions can they be related? Three main frequency components represented by power peaks at <1 Hz, 1-2 Hz and 2-8 Hz seem to feature the response activities of PG. (a) The aversive odorants induce odorant-specific patterns represented by peak power frequencies at <1 Hz. (b) The oscillation at approximately 1 Hz, which exists intrinsically in the Helix PG, can be specifically enhanced by appetitive odors. Activities induced in the procerebrum (PC), the visceral ganglion (VG) and PG by appetitive odorants, such as ethanol and apple, peak at 1.3-2 Hz, whereas those induced by aversive ones, such as formic acid and onion at <1 Hz. (c) The 2-8 Hz components always accompany the odorant-evoked activities of the PG either as the second or third strongest component, or in the form of conspicuous, long-lasting approximately 3 Hz oscillations. (d) The nonspecific odor-evoked 1-2 Hz and approximately 3 Hz activities, and the intrinsic approximately 1 Hz activity of the PG seem to be interrelated by a degree of mutual exclusion. We may therefore consider these activities as elementary, slow components that are involved in the processing of signals in this ganglion. It can be inferred from the findings in other invertebrates that the 1-3 Hz spontaneous discharge is strongly connected with motor activity that involves the feedback mechanism of the procerebro-cerebro-buccal or -procerebro-cerebro-pedal circuit. Our approach differs from most others reported so far in the following aspects: (i) use of gross steel electrodes for recording population activities; (ii) lengthy stimulation (10 min); (iii) long observation during and after stimulation; (iv) power spectral presentation of temporal evolution of activity patterns; (v) estimation of peak power frequency by Frequency-Amplitude Plot (FAP) (obtained from signals averaged in the frequency domain; a method based on systems theory).
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Affiliation(s)
- A Schütt
- Institute of Physiology, Medical University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
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Abstract
Evidence is reviewed to evaluate whether the term "brain is justified in referring to the snail's cerebral ganglion. The focus of the review is terrestrial species, with particular attention given to the genus Helix. In accordance with a standard definition of "brain, the cerebral ganglion is found to be differentiated both structurally and functionally. It receives convergent sensory inputs from a variety of anterior sensory organs plus the posterior body wall. Its outputs comprise motor commands directed towards anterior muscle systems, e.g., the tentacles and the penis, as well as premotor commands directed towards executory centers in other ganglia, e.g., the buccal, visceral, and pedal ganglia. Of the three major divisions in the ganglion, the procerebrum and the mesocerebrum are the most differentiated, whereas the metacerebrum is the least differentiated. The specializations of the procerebrum for olfactory functions, and the mesocerebrum for reproductive functions, reflect the importance of adaptations for feeding and mating in the evolution of the Gastropoda.
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Affiliation(s)
- R Chase
- Department of Biology, McGill University, Montreal, Quebec, H3A 1B1 Canada.
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Koene JM, Jansen RF, Ter Maat A, Chase R. A conserved location for the central nervous system control of mating behaviour in gastropod molluscs: evidence from a terrestrial snail. J Exp Biol 2000; 203:1071-80. [PMID: 10683166 DOI: 10.1242/jeb.203.6.1071] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have investigated the role of the right mesocerebrum in the expression of mating behaviour in the garden snail Helix aspersa. Using an in vivo stimulation and recording technique, we provide evidence for both sensory and motor functions in the mesocerebral neuronal population. Some neurones were specifically sensitive to tactile stimuli delivered to the skin on the superior tentacles and around the genital pore. Electrical stimulation of the right mesocerebrum evoked genital eversion and, in combination with tactile stimulation, dart-shooting and penial eversion. Genital eversions were also elicited by injections of APGWamide. During courtship, one recorded unit increased its activity only in correlation with penial eversion, while six other units increased their activity only during dart-shooting. Three additional units increased their activity during both types of behaviour. In addition, most of the recorded units showed increased neuronal activity during times of contact with a partner. Comparison of our results with available data from other molluscs leads us to conclude that the right anteromedial region of the cerebral ganglion is an evolutionarily conserved region of the gastropod brain specialised for the control of male mating behaviour. It is striking to find such functional conservation in the central nervous system of phylogenetically distant gastropods given the large differences in behaviour during mating.
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Affiliation(s)
- J M Koene
- Department of Biology, McGill University, Montréal, Québec, H3A 1B1 Canada and Faculty of Biology, Vrije Universiteit, De Boelelaan 1087, The Netherlands.
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Gelperin A, Flores J, Raccuia-Behling F, Cooke IR. Nitric oxide and carbon monoxide modulate oscillations of olfactory interneurons in a terrestrial mollusk. J Neurophysiol 2000; 83:116-27. [PMID: 10634858 DOI: 10.1152/jn.2000.83.1.116] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spontaneous or odor-induced oscillations in local field potential are a general feature of olfactory processing centers in a large number of vertebrate and invertebrate species. The ubiquity of such oscillations in the olfactory bulb of vertebrates and analogous structures in arthropods and mollusks suggests that oscillations are fundamental to the computations performed during processing of odor stimuli. Diffusible intercellular messengers such as nitric oxide (NO) and carbon monoxide (CO) also are associated with central olfactory structures in a wide array of species. We use the procerebral (PC) lobe of the terrestrial mollusk Limax maximus to demonstrate a role for NO and CO in the oscillatory dynamics of the PC lobe: synthesizing enzymes for NO and CO are associated with the PC lobes of Limax, application of NO to the Limax PC lobe increases the local field potential oscillation frequency, whereas block of NO synthesis slows or stops the oscillation, the bursting cells of the PC lobe that drive the field potential oscillation are driven to higher burst frequency by application of NO, the nonbursting cells of the PC lobe receive trains of inhibitory postsynaptic potentials, presumably from bursting cells, due to application of NO, and application of CO to the PC lobe by photolysis of caged CO results in an increase in oscillation frequency proportional to CO dosage.
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Affiliation(s)
- A Gelperin
- Biological Computation Research Department, Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974, USA.
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Odorant-induced low-frequency activities of the Helix pedal ganglion are odorant-specific and related to behavior. Comp Biochem Physiol A Mol Integr Physiol 1999. [DOI: 10.1016/s1095-6433(99)00112-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Hernádi L, Elekes K. Topographic organization of serotonergic and dopaminergic neurons in the cerebral ganglia and their peripheral projection patterns in the head areas of the snail Helix pomatia. J Comp Neurol 1999; 411:274-87. [PMID: 10404253 DOI: 10.1002/(sici)1096-9861(19990823)411:2<274::aid-cne8>3.0.co;2-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The distribution of monoaminergic neurons within the cerebral ganglia was investigated in the pulmonate snail Helix pomatia. Simultaneous serotonin and tyrosine hydroxylase double immunostaining revealed that the immunoreactive cell groups are concentrated in a putative monoaminergic center on the ventral surface of the cerebral ganglia. Simultaneous cobalt (Co)- and nickel (Ni)-lysine backfills of cerebral nerves were combined with 5, 6-dihydroxytryptamine pigment-labelling of serotonergic neurons, or with fluorescence immunocytochemistry of dopaminergic neurons. This showed that the serotonergic and dopaminergic cell groups can be divided into smaller subgroups on the basis of their axonal projections into different cerebral nerves. These subgroups show a topographic organization within the serotonergic and dopaminergic neuronal clusters. In the serotonergic system, the different regions of the head are represented in a rostrocaudal direction, whereas a caudorostral organization is characteristic for the dopaminergic system. No serotonin- or dopamine-immunoreative cell bodies but numerous fibers were observed in the head areas, indicating that these are innervated by cerebral monoaminergic neurons and show different innervation patterns. Serotonin-immunoreactive fibers mostly innervate muscle fibers, whereas dopamine-immunoreactive processes do not innervate effector cells, but terminate within the nerve branches of the head areas. On the basis of their innervation pattern, we suggest that dopaminergic neurons may take part in en route modulation of sensory afferent and efferent processes in an as yet unknown manner. The serotonergic neurons, on the other hand, may play a direct role in the modulation of muscle function.
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Affiliation(s)
- L Hernádi
- Balaton Limnological Research Institute of the Hungarian Academy of Sciences, Tihany H-8237, Hungary.
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Schütt A, Başar E, Bullock T. Power spectra of ongoing activity of the snail brain can discriminate odorants. Comp Biochem Physiol A Mol Integr Physiol 1999. [DOI: 10.1016/s1095-6433(99)00045-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ermentrout B, Flores J, Gelperin A. Minimal model of oscillations and waves in the Limax olfactory lobe with tests of the model's predictive power. J Neurophysiol 1998; 79:2677-89. [PMID: 9582238 DOI: 10.1152/jn.1998.79.5.2677] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Propagating waves are observed in the olfactory or procerebral (PC) lobe of the terrestrial mollusk, Limax maximus. Wave propagation is altered by cutting through the various layers of the PC lobe both parallel and transverse to the direction of wave propagation. We present a model for the PC lobe based on two layers of coupled cells. The top layer represents the cell layer of the PC lobe, and the bottom layer corresponds to the neuropil of the PC lobe. To get wave propagation, we induce a coupling gradient so that the most apical cells receive a greater input from neighbors than the basal cells. The top layer in the model is composed of oscillators coupled locally, whereas the bottom layer is comprised of oscillators with global coupling. Odor stimulation is represented by an increase in the strength of coupling between the two layers. This model allows us to explain a number of experimental observations: 1) the intact PC lobe exhibits regular propagating waves, which travel from the apical to the basal end; 2) there is a gradient in the local frequency of slices cut transverse to the axis of wave propagation, with apical slices oscillating faster than basal slices; 3) with partial cuts through the cell layer or the neuropil layer, the apical and basal ends remain tightly coupled; 4) removal of the neuropil layer does not prevent wave propagation in the cell layer; 5) odor stimulation causes the waves to collapse and the cells in the PC lobe oscillate synchronously; and 6) by allowing a single parameter to vary in the model, we capture the reversal of waves in low chloride medium.
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Affiliation(s)
- B Ermentrout
- Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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