1
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Freiler MK, Smith GT. Neuroendocrine mechanisms contributing to the coevolution of sociality and communication. Front Neuroendocrinol 2023; 70:101077. [PMID: 37217079 PMCID: PMC10527162 DOI: 10.1016/j.yfrne.2023.101077] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 04/19/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023]
Abstract
Communication is inherently social, so signaling systems should evolve with social systems. The 'social complexity hypothesis' posits that social complexity necessitates communicative complexity and is generally supported in vocalizing mammals. This hypothesis, however, has seldom been tested outside the acoustic modality, and comparisons across studies are confounded by varying definitions of complexity. Moreover, proximate mechanisms underlying coevolution of sociality and communication remain largely unexamined. In this review, we argue that to uncover how sociality and communication coevolve, we need to examine variation in the neuroendocrine mechanisms that coregulate social behavior and signal production and perception. Specifically, we focus on steroid hormones, monoamines, and nonapeptides, which modulate both social behavior and sensorimotor circuits and are likely targets of selection during social evolution. Lastly, we highlight weakly electric fishes as an ideal system in which to comparatively address the proximate mechanisms underlying relationships between social and signal diversity in a novel modality.
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Affiliation(s)
- Megan K Freiler
- Department of Biology, Indiana University, Bloomington, IN, United States; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, United States.
| | - G Troy Smith
- Department of Biology, Indiana University, Bloomington, IN, United States; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, United States
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2
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Dwortz MF, Curley JP, Tye KM, Padilla-Coreano N. Neural systems that facilitate the representation of social rank. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200444. [PMID: 35000438 PMCID: PMC8743891 DOI: 10.1098/rstb.2020.0444] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 11/10/2021] [Indexed: 12/15/2022] Open
Abstract
Across species, animals organize into social dominance hierarchies that serve to decrease aggression and facilitate survival of the group. Neuroscientists have adopted several model organisms to study dominance hierarchies in the laboratory setting, including fish, reptiles, rodents and primates. We review recent literature across species that sheds light onto how the brain represents social rank to guide socially appropriate behaviour within a dominance hierarchy. First, we discuss how the brain responds to social status signals. Then, we discuss social approach and avoidance learning mechanisms that we propose could drive rank-appropriate behaviour. Lastly, we discuss how the brain represents memories of individuals (social memory) and how this may support the maintenance of unique individual relationships within a social group. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.
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Affiliation(s)
- Madeleine F. Dwortz
- Department of Psychology, University of Texas at Austin, Austin, TX 78712, USA
- Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712, USA
| | - James P. Curley
- Department of Psychology, University of Texas at Austin, Austin, TX 78712, USA
| | - Kay M. Tye
- Systems Neuroscience Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Nancy Padilla-Coreano
- Systems Neuroscience Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Department of Neuroscience, University of Florida, Gainesville, FN 32611, USA
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3
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Thompson WA, Shvartsburd Z, Vijayan MM. Sex-Specific and Long-Term Impacts of Early-Life Venlafaxine Exposure in Zebrafish. BIOLOGY 2022; 11:250. [PMID: 35205116 PMCID: PMC8869491 DOI: 10.3390/biology11020250] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/25/2022] [Accepted: 01/31/2022] [Indexed: 02/04/2023]
Abstract
Venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor, is a widely prescribed antidepressant that is detected in municipal wastewater effluents at µg/L concentrations. It has been shown to impact the early life stages of fish, including neurodevelopment and behaviour in larvae, but whether such early exposures have longer-term consequences are far from clear. Here, we sought to determine whether zygotic deposition of venlafaxine, mimicking a maternal transfer scenario, disturbs the metabolic rate and behavioural performance using zebrafish (Danio rerio). This was tested using freshly fertilized embryos (1-4 cell stage) microinjected with either 0, 1 or 10 ng of venlafaxine and raised to either juvenile (60 days post-fertilization) or adult (10-12 months post-fertilization). Zygotic venlafaxine exposure led to a reduction in the active metabolic rate and aerobic scope, but this was only observed in female fish. On the other hand, the total distance travelled in an open field assessment was greater at the highest concentration of venlafaxine only in the adult males. At the juvenile stage, behavioural assessments demonstrated that venlafaxine exposure may increase boldness-including hyperactivity, lower thigmotaxis, and a reduction in the distance to a novel object. Taken together, these results demonstrate that zygotic venlafaxine exposure may impact developmental programming in a sex-specific manner in fish.
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Affiliation(s)
| | | | - Mathilakath M. Vijayan
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (W.A.T.); (Z.S.)
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4
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Wallach A, Melanson A, Longtin A, Maler L. Mixed selectivity coding of sensory and motor social signals in the thalamus of a weakly electric fish. Curr Biol 2021; 32:51-63.e3. [PMID: 34741807 DOI: 10.1016/j.cub.2021.10.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/31/2021] [Accepted: 10/14/2021] [Indexed: 11/16/2022]
Abstract
High-level neural activity often exhibits mixed selectivity to multivariate signals. How such representations arise and modulate natural behavior is poorly understood. We addressed this question in weakly electric fish, whose social behavior is relatively low dimensional and can be easily reproduced in the laboratory. We report that the preglomerular complex, a thalamic region exclusively connecting midbrain with pallium, implements a mixed selectivity strategy to encode interactions related to courtship and rivalry. We discuss how this code enables the pallial recurrent networks to control social behavior, including dominance in male-male competition and female mate selection. Notably, response latency analysis and computational modeling suggest that corollary discharge from premotor regions is implicated in flagging outgoing communications and thereby disambiguating self- versus non-self-generated signals. These findings provide new insights into the neural substrates of social behavior, multi-dimensional neural representation, and its role in perception and decision making.
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Affiliation(s)
- Avner Wallach
- Zuckerman Institute of Mind, Brain and Behavior, Columbia University, 3227 Broadway, NY 10027, USA.
| | - Alexandre Melanson
- Département de Physique et d'Astronomie, Université de Moncton, 18 Av. Antonine-Maillet, Moncton, NB E1A 3E9, Canada; Department of Physics, University of Ottawa, 150 Louis-Pasteur Pvt, Ottawa, ON K1N 6N5, Canada
| | - André Longtin
- Department of Physics, University of Ottawa, 150 Louis-Pasteur Pvt, Ottawa, ON K1N 6N5, Canada; Center for Neural Dynamics, Brain and Mind Research Institute, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Leonard Maler
- Center for Neural Dynamics, Brain and Mind Research Institute, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
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5
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Dunlap KD, Koukos HM, Chagnaud BP, Zakon HH, Bass AH. Vocal and Electric Fish: Revisiting a Comparison of Two Teleost Models in the Neuroethology of Social Behavior. Front Neural Circuits 2021; 15:713105. [PMID: 34489647 PMCID: PMC8418312 DOI: 10.3389/fncir.2021.713105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/12/2021] [Indexed: 11/30/2022] Open
Abstract
The communication behaviors of vocal fish and electric fish are among the vertebrate social behaviors best understood at the level of neural circuits. Both forms of signaling rely on midbrain inputs to hindbrain pattern generators that activate peripheral effectors (sonic muscles and electrocytes) to produce pulsatile signals that are modulated by frequency/repetition rate, amplitude and call duration. To generate signals that vary by sex, male phenotype, and social context, these circuits are responsive to a wide range of hormones and neuromodulators acting on different timescales at multiple loci. Bass and Zakon (2005) reviewed the behavioral neuroendocrinology of these two teleost groups, comparing how the regulation of their communication systems have both converged and diverged during their parallel evolution. Here, we revisit this comparison and review the complementary developments over the past 16 years. We (a) summarize recent work that expands our knowledge of the neural circuits underlying these two communication systems, (b) review parallel studies on the action of neuromodulators (e.g., serotonin, AVT, melatonin), brain steroidogenesis (via aromatase), and social stimuli on the output of these circuits, (c) highlight recent transcriptomic studies that illustrate how contemporary molecular methods have elucidated the genetic regulation of social behavior in these fish, and (d) describe recent studies of mochokid catfish, which use both vocal and electric communication, and that use both vocal and electric communication and consider how these two systems are spliced together in the same species. Finally, we offer avenues for future research to further probe how similarities and differences between these two communication systems emerge over ontogeny and evolution.
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Affiliation(s)
- Kent D Dunlap
- Department of Biology, Trinity College, Hartford, CT, United States
| | - Haley M Koukos
- Department of Biology, Trinity College, Hartford, CT, United States
| | - Boris P Chagnaud
- Institute of Biology, Karl-Franzens-University Graz, Graz, Austria
| | - Harold H Zakon
- Department of Neuroscience, University of Texas at Austin, Austin, TX, United States.,Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States
| | - Andrew H Bass
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, United States
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6
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Timothy M, Forlano PM. Serotonin distribution in the brain of the plainfin midshipman: Substrates for vocal-acoustic modulation and a reevaluation of the serotonergic system in teleost fishes. J Comp Neurol 2020; 528:3451-3478. [PMID: 32361985 DOI: 10.1002/cne.24938] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/27/2020] [Accepted: 04/27/2020] [Indexed: 12/18/2022]
Abstract
Serotonin (5-HT) is a modulator of neural circuitry underlying motor patterning, homeostatic control, and social behavior. While previous studies have described 5-HT distribution in various teleosts, serotonergic raphe subgroups in fish are not well defined and therefore remain problematic for cross-species comparisons. Here we used the plainfin midshipman fish, Porichthys notatus, a well-studied model for investigating the neural and hormonal mechanisms of vertebrate vocal-acoustic communication, to redefine raphe subgroups based on both stringent neuroanatomical landmarks as well as quantitative cell measurements. In addition, we comprehensively characterized 5-HT-immunoreactive (-ir) innervation throughout the brain, including well-delineated vocal and auditory nuclei. We report neuroanatomical heterogeneity in populations of the serotonergic raphe nuclei of the brainstem reticular formation, with three discrete subregions in the superior raphe, an intermediate 5-HT-ir cell cluster, and an extensive inferior raphe population. 5-HT-ir neurons were also observed within the vocal motor nucleus (VMN), forming putative contacts on those cells. In addition, three major 5-HT-ir cell groups were identified in the hypothalamus and one group in the pretectum. Significant 5-HT-ir innervation was found in components of the vocal pattern generator and cranial motor nuclei. All vocal midbrain nuclei showed considerable 5-HT-ir innervation, as did thalamic and hindbrain auditory and lateral line areas and vocal-acoustic integration sites in the preoptic area and ventral telencephalon. This comprehensive atlas offers new insights into the organization of 5-HT nuclei in teleosts and provides neuroanatomical evidence for serotonin as a modulator of vocal-acoustic circuitry and behavior in midshipman fish, consistent with findings in vocal tetrapods.
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Affiliation(s)
- Miky Timothy
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, New York, 11210, USA
| | - Paul M Forlano
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, New York, 11210, USA.,Biology Subprogram in Ecology, Evolution, and Behavior, The Graduate Center, City University of New York, 365 5th Avenue, New York, New York, 10016, USA.,Biology Subprogram in Neuroscience, The Graduate Center, City University of New York, 365 5th Avenue, New York, New York, 10016, USA.,Psychology Subprogram in Behavioral and Cognitive Neuroscience, The Graduate Center, City University of New York, 365 5th Avenue, New York, New York, 10016, USA.,Aquatic Research and Environmental Assessment Center, Brooklyn College, Brooklyn, New York, USA
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7
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Borland JM, Rilling JK, Frantz KJ, Albers HE. Sex-dependent regulation of social reward by oxytocin: an inverted U hypothesis. Neuropsychopharmacology 2019; 44:97-110. [PMID: 29968846 PMCID: PMC6235847 DOI: 10.1038/s41386-018-0129-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/10/2018] [Accepted: 06/15/2018] [Indexed: 12/17/2022]
Abstract
The rewarding properties of social interactions are essential for the expression of social behavior and the development of adaptive social relationships. Here, we review sex differences in social reward, and more specifically, how oxytocin (OT) acts in the mesolimbic dopamine system (MDS) to mediate the rewarding properties of social interactions in a sex-dependent manner. Evidence from rodents and humans suggests that same-sex social interactions may be more rewarding in females than in males. We propose that there is an inverted U relationship between OT dose, social reward, and neural activity within structures of the MDS in both males and females, and that this dose-response relationship is initiated at lower doses in females than males. As a result, depending on the dose of OT administered, OT could reduce social reward in females, while enhancing it in males. Sex differences in the neural mechanisms regulating social reward may contribute to sex differences in the incidence of a large number of psychiatric and neurodevelopmental disorders. This review addresses the potential significance of a sex-dependent inverted U dose-response function for OT's effects on social reward and in the development of gender-specific therapies for these disorders.
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Affiliation(s)
- Johnathan M Borland
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - James K Rilling
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA
- Anthropology, Emory University, Atlanta, GA, USA
- Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
- Center for Translational and Social Neuroscience, Emory University, Atlanta, GA, USA
| | - Kyle J Frantz
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - H Elliott Albers
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA.
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA.
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8
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Subsecond Sensory Modulation of Serotonin Levels in a Primary Sensory Area and Its Relation to Ongoing Communication Behavior in a Weakly Electric Fish. eNeuro 2016; 3:eN-NWR-0115-16. [PMID: 27844054 PMCID: PMC5093153 DOI: 10.1523/eneuro.0115-16.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 10/14/2016] [Accepted: 10/15/2016] [Indexed: 01/19/2023] Open
Abstract
Serotonergic neurons of the raphe nuclei of vertebrates project to most regions of the brain and are known to significantly affect sensory processing. The subsecond dynamics of sensory modulation of serotonin levels and its relation to behavior, however, remain unknown. We used fast-scan cyclic voltammetry to measure serotonin release in the electrosensory system of weakly electric fish, Apteronotus leptorhynchus. These fish use an electric organ to generate a quasi-sinusoidal electric field for communicating with conspecifics. In response to conspecific signals, they frequently produce signal modulations called chirps. We measured changes in serotonin concentration in the hindbrain electrosensory lobe (ELL) with a resolution of 0.1 s concurrently with chirping behavior evoked by mimics of conspecific electric signals. We show that serotonin release can occur phase locked to stimulus onset as well as spontaneously in the ELL region responsible for processing these signals. Intense auditory stimuli, on the other hand, do not modulate serotonin levels in this region, suggesting modality specificity. We found no significant correlation between serotonin release and chirp production on a trial-by-trial basis. However, on average, in the trials where the fish chirped, there was a reduction in serotonin release in response to stimuli mimicking similar-sized same-sex conspecifics. We hypothesize that the serotonergic system is part of an intricate sensory–motor loop: serotonin release in a sensory area is triggered by sensory input, giving rise to motor output, which can in turn affect serotonin release at the timescale of the ongoing sensory experience and in a context-dependent manner.
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9
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Pitchers WR, Constantinou SJ, Losilla M, Gallant JR. Electric fish genomics: Progress, prospects, and new tools for neuroethology. ACTA ACUST UNITED AC 2016; 110:259-272. [PMID: 27769923 DOI: 10.1016/j.jphysparis.2016.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/06/2016] [Accepted: 10/16/2016] [Indexed: 01/01/2023]
Abstract
Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21st century biological questions. This review article considers the molecular data collected for weakly electric fish over the past three decades, and the insights that data of this nature has motivated. For readers relatively new to molecular genetics techniques, we also provide a table of terminology aimed at clarifying the numerous acronyms and techniques that accompany this field. Next, we pose a research agenda for expanding genomic resources for electric fish research over the next 10years. We conclude by considering some of the exciting research prospects for neuroethology that electric fish genomics may offer over the coming decades, if the electric fish community is successful in these endeavors.
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Affiliation(s)
- William R Pitchers
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
| | - Savvas J Constantinou
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Mauricio Losilla
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Jason R Gallant
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
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10
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Larson EA, Metzen MG, Chacron MJ. Serotonin modulates electrosensory processing and behavior via 5-HT2-like receptors. Neuroscience 2014; 271:108-18. [PMID: 24780766 DOI: 10.1016/j.neuroscience.2014.04.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/17/2014] [Accepted: 04/21/2014] [Indexed: 11/16/2022]
Abstract
Efficient sensory processing of the environment is a critical function for any organism to survive and is accomplished by having neurons adapt their responses to stimuli based on behavioral context in part through neuromodulators such as serotonin (5-HT). We have recently shown that one critical function of the serotonergic system in weakly electric fish is to enhance sensory pyramidal neuron responses within the electrosensory lateral line lobe (ELL) to stimuli caused by same sex conspecifics, thereby enhancing their perception. This enhancement is accomplished by making pyramidal neurons more excitable through downregulation of potassium channels. However, the nature of the 5-HT receptors that mediate this effect is not known. Here we show that the 5-HT2 receptor antagonist ketanserin (ket) can effectively block the effects of 5-HT on pyramidal neuron excitability in vitro. Indeed, 5-HT application subsequent to ket application did not cause any significant changes in neuron excitability and responses to current injection. We further show that ket applied in vivo can block the effects of 5-HT on behavioral responses. Thus, our results strongly suggest that the previously observed effects of 5-HT on sensory processing within ELL and their consequences for behavior are mediated by 5-HT2 receptors.
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Affiliation(s)
- E A Larson
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - M G Metzen
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - M J Chacron
- Department of Physiology, McGill University, Montreal, QC, Canada; Department of Physics, McGill University, Montreal, QC, Canada.
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11
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Dunlap KD, Chung M, Castellano JF. Influence of long-term social interaction on chirping behavior, steroid levels and neurogenesis in weakly electric fish. ACTA ACUST UNITED AC 2014; 216:2434-41. [PMID: 23761468 DOI: 10.1242/jeb.082875] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Social interactions dramatically affect the brain and behavior of animals. Studies in birds and mammals indicate that socially induced changes in adult neurogenesis participate in the regulation of social behavior, but little is known about this relationship in fish. Here, we review studies in electric fish (Apteronotus leptorhychus) that link social stimulation, changes in electrocommunication behavior and adult neurogenesis in brain regions associated with electrocommunication. Compared with isolated fish, fish living in pairs have greater production of chirps, an electrocommunication signal, during dyadic interactions and in response to standardized artificial social stimuli. Social interaction also promotes neurogenesis in the periventricular zone, which contributes born cells to the prepacemaker nucleus, the brain region that regulates chirping. Both long-term chirp rate and periventricular cell addition depend on the signal dynamics (amplitude and waveform variation), modulations (chirps) and novelty of the stimuli from the partner fish. Socially elevated cortisol levels and cortisol binding to glucocorticoid receptors mediate, at least in part, the effect of social interaction on chirping behavior and brain cell addition. In a closely related electric fish (Brachyhypopomus gauderio), social interaction enhances cell proliferation specifically in brain regions for electrocommunication and only during the breeding season, when social signaling is most elaborate. Together, these studies demonstrate a consistent correlation between brain cell addition and environmentally regulated chirping behavior across many social and steroidal treatments and suggest a causal relationship.
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Affiliation(s)
- Kent D Dunlap
- Department of Biology, Trinity College, Hartford, CT 06106, USA.
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12
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Smith GT. Evolution and hormonal regulation of sex differences in the electrocommunication behavior of ghost knifefishes (Apteronotidae). ACTA ACUST UNITED AC 2014; 216:2421-33. [PMID: 23761467 DOI: 10.1242/jeb.082933] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ghost knifefishes (family Apteronotidae) are one of the most successful and diverse families of electric fish. Like other weakly electric fish, apteronotids produce electric organ discharges (EODs) that function in electrolocation and communication. This review highlights the diversity in the structure, function and sexual dimorphism of electrocommunication signals within and across apteronotid species. EOD frequency (EODf) and waveform vary as a function of species, sex and/or social rank. Sex differences in EODf are evolutionarily labile; apteronotid species express every pattern of sexual dimorphism in EODf (males>females; males<females; males=females). The direction and magnitude of sex differences in EODf are correlated across species and populations with the responsiveness of EODf to androgens and/or estrogens, which suggests that sex differences evolve through gains and/or losses of hormone sensitivity. During social interactions, apteronotids also modulate their EODs to produce motivational signals known as chirps. Chirp structure differs markedly across species, and many species produce two or more discrete chirp types with potentially different functions. The structure of chirps is sexually dimorphic in all apteronotid species, and chirping is influenced by gonadal steroids and by neuromodulators. Encoding of chirps by the electrosensory system depends on the social context created by the interactions of the EODs of signalers and receivers. Electrosensory systems may thus influence the evolution of signal structure and function, and neuromodulators may coordinately shape the production and reception of electrocommunication signals depending on social context.
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Affiliation(s)
- G Troy Smith
- Department of Biology, Program in Neuroscience, and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA.
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13
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Giassi ACC, Duarte TT, Ellis W, Maler L. Organization of the gymnotiform fish pallium in relation to learning and memory: II. Extrinsic connections. J Comp Neurol 2013; 520:3338-68. [PMID: 22430442 DOI: 10.1002/cne.23109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This study describes the extrinsic connections of the dorsal telencephalon (pallium) of gymnotiform fish. We show that the afferents to the dorsolateral and dorsomedial pallial subdivisions of gymnotiform fish arise from the preglomerular complex. The preglomerular complex receives input from four clearly distinct regions: (1) descending input from the pallium itself (dorsomedial and dorsocentral subdivisions and nucleus taenia); (2) other diencephalic nuclei (centroposterior, glomerular, and anterior tuberal nuclei and nucleus of the posterior tuberculum); (3) mesencephalic sensory structures (optic tectum, dorsal and ventral torus semicircularis); and (4) basal forebrain, preoptic area, and hypothalamic nuclei. Previous studies have implicated the majority of the diencephalic and mesencephalic nuclei in electrosensory, visual, and acousticolateral functions. Here we discuss the implications of preglomerular/pallial electrosensory-associated afferents with respect to a major functional dichotomy of the electric sense. The results allow us to hypothesize that a functional distinction between electrocommunication vs. electrolocation is maintained within the input and output pathways of the gymnotiform pallium. Electrocommunication information is conveyed to the pallium through complex indirect pathways that originate in the nucleus electrosensorius, whereas electrolocation processing follows a conservative pathway inherent to all vertebrates, through the optic tectum. We hypothesize that cells responsive to communication signals do not converge onto the same targets in the preglomerular complex as cells responsive to moving objects. We also hypothesize that efferents from the dorsocentral (DC) telencephalon project to the dorsal torus semicircularis to regulate processing of electrocommunication signals, whereas DC efferents to the tectum modulate sensory control of movement.
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Affiliation(s)
- Ana C C Giassi
- Department of Cell and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
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14
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Zubizarreta L, Perrone R, Stoddard PK, Costa G, Silva AC. Differential serotonergic modulation of two types of aggression in weakly electric fish. Front Behav Neurosci 2012. [PMID: 23181014 PMCID: PMC3500767 DOI: 10.3389/fnbeh.2012.00077] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Agonistic aggression has provided an excellent framework to study how conserved circuits and neurochemical mediators control species-specific and context-dependent behavior. The principal inhibitory control upon aggression is serotonin (5-HT) dependent, and the activation of 5-HT(1A) receptors is involved in its action. To address whether the serotonergic system differentially regulates different types of aggression, we used two species of weakly electric fish: the solitary Gymnotus omarorum and the gregarious Brachyhypopomus gauderio, which display distinctive types of aggression as part of each species' natural behavioral repertoire. We found that in the reproduction-related aggression displayed by B. gauderio after conflict resolution, the serotonergic activity follows the classic pattern in which subordinates exhibit higher 5-HT levels than controls. After the territorial aggression displayed by G. omarorum, however, both dominants and subordinates show lower 5-HT levels than controls, indicating a different response of the serotonergic system. Further, we found interspecific differences in basal serotonin turnover and in the dynamic profile of the changes in 5-HT levels from pre-contest to post-contest. Finally, we found the expected reduction of aggression and outcome shift in the territorial aggression of G. omarorum after 8-OH-DPAT (5-HT(1A) receptor agonist) administration, but no effect in the reproduction-related aggression of B. gauderio. Our results demonstrate the differential participation of the serotonergic system in the modulation of two types of aggression that we speculate may be a general strategy of the neuroendocrine control of aggression across vertebrates.
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Affiliation(s)
- Lucía Zubizarreta
- Unidad Bases Neurales de la Conducta, Instituto de Investigaciones Biológicas Clemente Estable Montevideo, Uruguay
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Walz H, Hupé GJ, Benda J, Lewis JE. The neuroethology of electrocommunication: how signal background influences sensory encoding and behaviour in Apteronotus leptorhynchus. ACTA ACUST UNITED AC 2012; 107:13-25. [PMID: 22981958 DOI: 10.1016/j.jphysparis.2012.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 07/05/2012] [Accepted: 07/19/2012] [Indexed: 10/27/2022]
Abstract
Weakly-electric fish are a well-established model system for neuroethological studies on communication and aggression. Sensory encoding of their electric communication signals, as well as behavioural responses to these signals, have been investigated in great detail under laboratory conditions. In the wave-type brown ghost knifefish, Apteronotus leptorhynchus, transient increases in the frequency of the generated electric field, called chirps, are particularly well-studied, since they can be readily evoked by stimulating a fish with artificial signals mimicking conspecifics. When two fish interact, both their quasi-sinusoidal electric fields (called electric organ discharge, EOD) superimpose, resulting in a beat, an amplitude modulation at the frequency difference between the two EODs. Although chirps themselves are highly stereotyped signals, the shape of the amplitude modulation resulting from a chirp superimposed on a beat background depends on a number of parameters, such as the beat frequency, modulation depth, and beat phase at which the chirp is emitted. Here we review the influence of these beat parameters on chirp encoding in the three primary stages of the electrosensory pathway: electroreceptor afferents, the hindbrain electrosensory lateral line lobe, and midbrain torus semicircularis. We then examine the role of these parameters, which represent specific features of various social contexts, on the behavioural responses of A. leptorhynchus. Some aspects of the behaviour may be explained by the coding properties of early sensory neurons to chirp stimuli. However, the complexity and diversity of behavioural responses to chirps in the context of different background parameters cannot be explained solely on the basis of the sensory responses and thus suggest that critical roles are played by higher processing stages.
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Affiliation(s)
- Henriette Walz
- Bernstein Center for Computational Neuroscience Munich, 82152 Martinsried, Germany
| | - Ginette J Hupé
- Department of Biology and Centre for Neural Dynamics, University of Ottawa, Ottawa, ON, Canada K1N 6N5
| | - Jan Benda
- Institute of Neurobiology, University of Tübingen, 72076 Tübingen, Germany.
| | - John E Lewis
- Department of Biology and Centre for Neural Dynamics, University of Ottawa, Ottawa, ON, Canada K1N 6N5
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Deemyad T, Maler L, Chacron MJ. Inhibition of SK and M channel-mediated currents by 5-HT enables parallel processing by bursts and isolated spikes. J Neurophysiol 2011; 105:1276-94. [PMID: 21209357 PMCID: PMC4850069 DOI: 10.1152/jn.00792.2010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although serotonergic innervation of sensory brain areas is ubiquitous, its effects on sensory information processing remain poorly understood. We investigated these effects in pyramidal neurons within the electrosensory lateral line lobe (ELL) of weakly electric fish. Surprisingly, we found that 5-HT is present at different levels across the different ELL maps; the presence of 5-HT fibers was highest in the map that processes intraspecies communication signals. Electrophysiological recordings revealed that 5-HT increased excitability and burst firing through a decreased medium afterhyperpolarization resulting from reduced small-conductance calcium-activated (SK) currents as well as currents mediated by an M-type potassium channel. We next investigated how 5-HT alters responses to sensory input. 5-HT application decreased the rheobase current, increased the gain, and decreased first spike latency. Moreover, it reduced discriminability between different stimuli, as quantified by the mutual information rate. We hypothesized that 5-HT shifts pyramidal neurons into a burst-firing mode where bursts, when considered as events, can detect the presence of particular stimulus features. We verified this hypothesis using signal detection theory. Our results indeed show that serotonin-induced bursts of action potentials, when considered as events, could detect specific stimulus features that were distinct from those detected by isolated spikes. Moreover, we show the novel result that isolated spikes transmit more information after 5-HT application. Our results suggest a novel function for 5-HT in that it enables differential processing by action potential patterns in response to current injection.
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Affiliation(s)
- Tara Deemyad
- Department of Physiology, McGill University, Montreal, Quebec, Canada
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Quintana L, Sierra F, Silva A, Macadar O. A central pacemaker that underlies the production of seasonal and sexually dimorphic social signals: functional aspects revealed by glutamate stimulation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2010; 197:211-25. [DOI: 10.1007/s00359-010-0603-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 09/21/2010] [Accepted: 10/17/2010] [Indexed: 01/31/2023]
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Hupé GJ, Lewis JE, Benda J. The effect of difference frequency on electrocommunication: Chirp production and encoding in a species of weakly electric fish, Apteronotus leptorhynchus. ACTA ACUST UNITED AC 2008; 102:164-72. [DOI: 10.1016/j.jphysparis.2008.10.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Smith GT, Combs N. Serotonergic activation of 5HT1A and 5HT2 receptors modulates sexually dimorphic communication signals in the weakly electric fish Apteronotus leptorhynchus. Horm Behav 2008; 54:69-82. [PMID: 18336816 DOI: 10.1016/j.yhbeh.2008.01.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 01/20/2008] [Accepted: 01/24/2008] [Indexed: 11/17/2022]
Abstract
Serotonin modulates agonistic and reproductive behavior across vertebrate species. 5HT(1A) and 5HT(1B) receptors mediate many serotonergic effects on social behavior, but other receptors, including 5HT(2) receptors, may also contribute. We investigated serotonergic regulation of electrocommunication signals in the weakly electric fish Apteronotus leptorhynchus. During social interactions, these fish modulate their electric organ discharges (EODs) to produce signals known as chirps. Males chirp more than females and produce two chirp types. Males produce high-frequency chirps as courtship signals; whereas both sexes produce low-frequency chirps during same-sex interactions. Serotonergic innervation of the prepacemaker nucleus, which controls chirping, is more robust in females than males. Serotonin inhibits chirping and may contribute to sexual dimorphism and individual variation in chirping. We elicited chirps with EOD playbacks and pharmacologically manipulated serotonin receptors to determine which receptors regulated chirping. We also asked whether serotonin receptor activation generally modulated chirping or more specifically targeted particular chirp types. Agonists and antagonists of 5HT(1B/1D) receptors (CP-94253 and GR-125743) did not affect chirping. The 5HT(1A) receptor agonist 8OH-DPAT specifically increased production of high-frequency chirps. The 5HT(2) receptor agonist DOI decreased chirping. Receptor antagonists (WAY-100635 and MDL-11939) opposed the effects of their corresponding agonists. These results suggest that serotonergic inhibition of chirping may be mediated by 5HT(2) receptors, but that serotonergic activation of 5HT(1A) receptors specifically increases the production of high-frequency chirps. The enhancement of chirping by 5HT(1A) receptors may result from interactions with cortisol and/or arginine vasotocin, which similarly enhance chirping and are influenced by 5HT(1A) activity in other systems.
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Affiliation(s)
- G Troy Smith
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
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Ellis LD, Maler L, Dunn RJ. Differential distribution of SK channel subtypes in the brain of the weakly electric fish Apteronotus leptorhynchus. J Comp Neurol 2008; 507:1964-78. [PMID: 18273887 DOI: 10.1002/cne.21597] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Calcium signals in vertebrate neurons can induce hyperpolarizing membrane responses through the activation of Ca(2+)-activated potassium channels. Of these, small conductance (SK) channels regulate neuronal responses through the generation of the medium after-hyperpolarization (mAHP). We have previously shown that an SK channel (AptSK2) contributes to signal processing in the electrosensory system of Apteronotus leptorhynchus. It was shown that for pyramidal neurons in the electrosensory lateral line lobe (ELL), AptSK2 expression selectively decreases responses to low-frequency signals. The localization of all the SK subunits throughout the brain of Apteronotus then became of substantial interest. We have now cloned two additional SK channel subunits from Apteronotus and determined the expression patterns of all three AptSK subunits throughout the brain. In situ hybridization experiments have revealed that, as in mammalian systems, the AptSK1 and 2 channels showed a partially overlapping expression pattern, whereas the AptSK3 channel was expressed in different brain areas. The AptSK1 and 2 channels were the primary subunits found in the major electrosensory processing areas. Immunohistochemistry further revealed distinct compartmentalization of the AptSK1 and 2 channels in the ELL. AptSK1 was localized to the apical dendrites of pyramidal neurons, whereas AptSK2 channels are primarily somatic. The distinct expression patterns of all three AptSK channels may reflect subtype-specific contributions to neuronal function, and the high homology between subtypes from a number of species suggests that the functional roles for each channel subtype are conserved from early vertebrate evolution.
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Affiliation(s)
- Lee D Ellis
- Department of Biology, McGill University, Montreal, QC H3G 1A4, Canada
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