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Kelly AM. A consideration of brain networks modulating social behavior. Horm Behav 2022; 141:105138. [PMID: 35219166 DOI: 10.1016/j.yhbeh.2022.105138] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/30/2022] [Accepted: 02/13/2022] [Indexed: 11/04/2022]
Abstract
A primary goal of the field of behavioral neuroendocrinology is to understand how the brain modulates complex behavior. Over the last 20 years we have proposed various brain networks to explain behavioral regulation, however, the parameters by which these networks are identified are often ill-defined and reflect our personal scientific biases based on our area of expertise. In this perspective article, I question our characterization of brain networks underlying behavior and their utility. Using the Social Behavior Network as a primary example, I outline issues with brain networks commonly discussed in the field of behavioral neuroendocrinology, argue that we reconsider how we identify brain networks underlying behavior, and urge the future use of analytical tools developed by the field of Network Neuroscience. With modern statistical/mathematical tools and state of the art technology for brain imaging, we can strive to minimize our bias and generate brain networks that may more accurately reflect how the brain produces behavior.
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Affiliation(s)
- Aubrey M Kelly
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States of America.
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2
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Davis SED, Sansone JM, Hurley LM. Postweaning Isolation Alters the Responses of Auditory Neurons to Serotonergic Modulation. Integr Comp Biol 2021; 61:302-315. [PMID: 33974061 DOI: 10.1093/icb/icab051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Juvenile social experience, such as social isolation, has profound effects on communicative behavior, including signal production and reception. In the current study, we explored responsiveness to the neuromodulator serotonin as a potential mechanistic link between early life social isolation and auditory processing. The serotonergic system is sensitive to social isolation in many brain regions including the inferior colliculus (IC), an auditory midbrain nucleus. We investigated the effects of social experience on serotonergic responsiveness by measuring cFos, an immediate early gene product, in the IC of female mice. Serotonin was manipulated pharmacologically by administering fenfluramine, pCPA, or saline to mice that had undergone an extreme dichotomy in social experience after weaning: being housed in social groups versus individually. These mice were exposed to a 60-min recording of vocalizations from an opposite-sex interaction and perfused. Using immunohistochemistry, we measured the density of cFos-positive (cFos+) nuclei in the major subdivisions of the IC. Housing condition, drug treatment, and IC subregion all had a significant effect on cFos+ density. The central IC showed the highest density of cFos+ cells and also the most pronounced effects of housing condition and drug treatment. In the central IC, cFos+ density was higher following fenfluramine treatment than saline, and lower following pCPA treatment than fenfluramine. Individually housed mice showed a higher cFos+ density than socially housed mice in both of the pharmacological treatment groups, but not in the saline group. Drug treatment but not housing condition had strong effects on the behaviors of grooming, digging, rearing, and movement. Once the effects of drug condition were controlled, there were no across-individual correlations between cFos+ densities and behaviors. These findings suggest that the responses of auditory neurons to neuromodulation by serotonin are influenced by early life experience.
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Affiliation(s)
- Sarah E D Davis
- Department of Biology, Indiana University, 1001 East Third Street, Bloomington, IN 47401, USA
| | - Jack M Sansone
- Department of Biology, Indiana University, 1001 East Third Street, Bloomington, IN 47401, USA
| | - Laura M Hurley
- Department of Biology, Indiana University, 1001 East Third Street, Bloomington, IN 47401, USA.,Center for the Integrative Study of Animal Behavior, 409 N Park Ave, Bloomington, IN 47408, USA
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3
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Thompson RR. An updated field guide for snark hunting: Comparative contributions to behavioral neuroendocrinology in the era of model organisms. Horm Behav 2020; 122:104742. [PMID: 32173444 DOI: 10.1016/j.yhbeh.2020.104742] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 03/07/2020] [Accepted: 03/10/2020] [Indexed: 12/23/2022]
Abstract
Studying neuroendocrine behavioral regulatory mechanisms in a variety of species across vertebrate groups is critical for determining how they work in natural contexts, how they evolved, and ultimately what can be generalized from them, potentially even to humans. All of the above are difficult, at best, if work within our field is exclusively done in traditional laboratory organisms. The importance of comparative approaches for understanding the relationships between hormones and behavior has been recognized and advocated for since our field's inception through a series of papers centered upon a poetic metaphor of Snarks and Boojums, all of which have articulated the benefits that come from studying a diverse range of species and the risks associated with a narrow focus on "model organisms." This mini-review follows in the footsteps of those powerful arguments, highlighting some of the comparative work since the latest interactions of the metaphor that has shaped how we think about three major conceptual frameworks within our field, two of them formalized - the Organization/Activation Model of sexual differentiation and the Social Brain Network - and one, context-dependency, that is generally associated with virtually all modern understandings of how hormones affect behavior. Comparative approaches are broadly defined as those in which the study of mechanism is placed within natural and/or evolutionary contexts, whether they directly compare different species or not. Studies are discussed in relation to how they have either extended or challenged generalities associated with the frameworks, how they have shaped subsequent work in model organisms to further elucidate neuroendocrine behavioral regulatory mechanisms, and how they have stimulated work to determine if and when similar mechanisms influence behavior in our own species.
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4
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Boyd SK. Effects of intracerebroventricular arginine vasotocin on a female amphibian proceptive behavior. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:505-513. [DOI: 10.1007/s00359-019-01340-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/29/2019] [Accepted: 05/02/2019] [Indexed: 10/26/2022]
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Städele C, DeMaegd ML, Stein W. State-Dependent Modification of Sensory Sensitivity via Modulation of Backpropagating Action Potentials. eNeuro 2018; 5:ENEURO.0283-18.2018. [PMID: 30225349 PMCID: PMC6140111 DOI: 10.1523/eneuro.0283-18.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 07/31/2018] [Indexed: 12/18/2022] Open
Abstract
Neuromodulators play a critical role in sensorimotor processing via various actions, including pre- and postsynaptic signal modulation and direct modulation of signal encoding in peripheral dendrites. Here, we present a new mechanism that allows state-dependent modulation of signal encoding in sensory dendrites by neuromodulatory projection neurons. We studied the impact of antidromic action potentials (APs) on stimulus encoding using the anterior gastric receptor (AGR) neuron in the heavily modulated crustacean stomatogastric ganglion (STG). We found that ectopic AP initiation in AGR's axon trunk is under direct neuromodulatory control by the inferior ventricular (IV) neurons, a pair of descending projection neurons. IV neuron activation elicited a long-lasting decrease in AGR ectopic activity. This modulation was specific to the site of AP initiation and could be mimicked by focal application of the IV neuron co-transmitter histamine. IV neuron actions were diminished after blocking H2 receptors in AGR's axon trunk, suggesting a direct axonal modulation. This local modulation did not affect the propagation dynamics of en passant APs. However, decreases in ectopic AP frequency prolonged sensory bursts elicited distantly near AGR's dendrites. This frequency-dependent effect was mediated via the reduction of antidromic APs, and the diminishment of backpropagation into the sensory dendrites. Computational models suggest that invading antidromic APs interact with local ionic conductances, the rate constants of which determine the sign and strength of the frequency-dependent change in sensory sensitivity. Antidromic APs therefore provide descending projection neurons with a means to influence sensory encoding without affecting AP propagation or stimulus transduction.
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Affiliation(s)
- Carola Städele
- Institute of Neurobiology, Ulm University, Ulm 89069, Germany
- School of Biological Sciences, Illinois State University, Normal, IL 61790
| | | | - Wolfgang Stein
- School of Biological Sciences, Illinois State University, Normal, IL 61790
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Forlano PM, Licorish RR, Ghahramani ZN, Timothy M, Ferrari M, Palmer WC, Sisneros JA. Attention and Motivated Response to Simulated Male Advertisement Call Activates Forebrain Dopaminergic and Social Decision-Making Network Nuclei in Female Midshipman Fish. Integr Comp Biol 2018; 57:820-834. [PMID: 28992072 DOI: 10.1093/icb/icx053] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Little is known regarding the coordination of audition with decision-making and subsequent motor responses that initiate social behavior including mate localization during courtship. Using the midshipman fish model, we tested the hypothesis that the time spent by females attending and responding to the advertisement call is correlated with the activation of a specific subset of catecholaminergic (CA) and social decision-making network (SDM) nuclei underlying auditory- driven sexual motivation. In addition, we quantified the relationship of neural activation between CA and SDM nuclei in all responders with the goal of providing a map of functional connectivity of the circuitry underlying a motivated state responsive to acoustic cues during mate localization. In order to make a baseline qualitative comparison of this functional brain map to unmotivated females, we made a similar correlative comparison of brain activation in females who were unresponsive to the advertisement call playback. Our results support an important role for dopaminergic neurons in the periventricular posterior tuberculum and ventral thalamus, putative A11 and A13 tetrapod homologues, respectively, as well as the posterior parvocellular preoptic area and dorsomedial telencephalon, (laterobasal amygdala homologue) in auditory attention and appetitive sexual behavior in fishes. These findings may also offer insights into the function of these highly conserved nuclei in the context of auditory-driven reproductive social behavior across vertebrates.
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Affiliation(s)
- Paul M Forlano
- Department of Biology, Brooklyn College, The City University of New York, Brooklyn, NY, USA.,Biology Subprogram in Ecology, Evolutionary Biology, and Behavior, The Graduate Center, City University of New York, New York, NY, USA.,Biology Subprogram in Neuroscience, The Graduate Center, City University of New York, New York, NY, USA.,Psychology Subprogram in Behavioral and Cognitive Neuroscience, The Graduate Center, City University of New York, New York, NY, USA.,Aquatic Research and Environmental Assessment Center, Brooklyn College, Brooklyn, NY, USA
| | - Roshney R Licorish
- Department of Biology, Brooklyn College, The City University of New York, Brooklyn, NY, USA
| | - Zachary N Ghahramani
- Department of Biology, Brooklyn College, The City University of New York, Brooklyn, NY, USA.,Biology Subprogram in Ecology, Evolutionary Biology, and Behavior, The Graduate Center, City University of New York, New York, NY, USA
| | - Miky Timothy
- Department of Biology, Brooklyn College, The City University of New York, Brooklyn, NY, USA
| | | | - William C Palmer
- Department of Psychology, University of Washington, Seattle, WA, USA
| | - Joseph A Sisneros
- Department of Psychology, University of Washington, Seattle, WA, USA.,Virginia Bloedel Hearing Research Center, Seattle, WA, USA
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Hanson JL, Hurley LM. Serotonin, estrus, and social context influence c-Fos immunoreactivity in the inferior colliculus. Behav Neurosci 2016; 130:600-613. [PMID: 27657308 PMCID: PMC5114148 DOI: 10.1037/bne0000165] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A fundamental task of sensory systems is to extract relevant social information from a range of environmental stimuli in the face of changing behavioral contexts and reproductive states. Neuromodulatory pathways that interact with such contextual variables are 1 mechanism for achieving this. In the mouse inferior colliculus (IC), a midbrain auditory region, the neuromodulator serotonin increases in females interacting with courting males, but events downstream of serotonin release have not been investigated. Here, we manipulated serotonin levels in female mice with the serotonin releaser fenfluramine or the serotonin depleter para-chlorophenylalaninemethyl ester (pCPA). Females were then exposed to an empty cage, a male partner, or a playback of courtship vocalizations, and the numbers of neurons in the IC with positive immunoreactivity for the immediate early gene product c-Fos were measured. The effects of drug treatments depended on social context and estrous state. Fenfluramine had greater effects in the nonsocial than in the partner social treatments. Females in proestrus or estrus and given fenfluramine had higher densities of c-Fos immunoreactive neurons, while females in diestrus had fewer immunoreactive neurons. The drug pCPA had the expected opposite effect of fenfluramine, causing a decreased response in pro/estrus females and an increased response in diestrus females. These findings show that the effects of serotonin on c-Fos activity in the IC of females is dependent on both external context and reproductive state, and suggest that these effects occur downstream of serotonin release. (PsycINFO Database Record
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9
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Chakraborty M, Burmeister SS. Effects of estradiol on neural responses to social signals in female túngara frogs. ACTA ACUST UNITED AC 2015; 218:3671-7. [PMID: 26449971 DOI: 10.1242/jeb.127738] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 09/21/2015] [Indexed: 11/20/2022]
Abstract
Estradiol plays an important role in mediating changes in female sexual behavior across reproductive cycles. In the túngara frog [Physalaemus (=Engystomops) pustulosus], the relationship between gonadal activity and female sexual behavior, as expressed by phonotaxis, is mediated primarily by estradiol. Estradiol receptors are expressed in auditory and motivational brain areas and the hormone could serve as an important modulator of neural responses to conspecific calls. To better understand how estradiol modifies neural responses to conspecific social signals, we manipulated estradiol levels and measured expression of the immediate early gene egr-1 in the auditory midbrain, thalamus and limbic forebrain in response to conspecific or heterospecific calls. We found that estradiol and conspecific calls increased egr-1 expression in the auditory midbrain and limbic forebrain, but in the thalamus, only conspecific calls were effective. In the preoptic area, estradiol enhanced the effect of the conspecific call on egr-1 expression, suggesting that the preoptic area could act as a hormonal gatekeeper to phonotaxis. Overall, the results suggest that estradiol has broad influences on the neural circuit involved in female reproduction, particularly those implicated in phonotaxis.
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Affiliation(s)
- Mukta Chakraborty
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Sabrina S Burmeister
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC 27599, USA
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Forlano PM, Kim SD, Krzyminska ZM, Sisneros JA. Catecholaminergic connectivity to the inner ear, central auditory, and vocal motor circuitry in the plainfin midshipman fish porichthys notatus. J Comp Neurol 2014; 522:2887-927. [PMID: 24715479 PMCID: PMC4107124 DOI: 10.1002/cne.23596] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 03/25/2014] [Accepted: 03/28/2014] [Indexed: 01/25/2023]
Abstract
Although the neuroanatomical distribution of catecholaminergic (CA) neurons has been well documented across all vertebrate classes, few studies have examined CA connectivity to physiologically and anatomically identified neural circuitry that controls behavior. The goal of this study was to characterize CA distribution in the brain and inner ear of the plainfin midshipman fish (Porichthys notatus) with particular emphasis on their relationship with anatomically labeled circuitry that both produces and encodes social acoustic signals in this species. Neurobiotin labeling of the main auditory end organ, the saccule, combined with tyrosine hydroxylase immunofluorescence (TH-ir) revealed a strong CA innervation of both the peripheral and central auditory system. Diencephalic TH-ir neurons in the periventricular posterior tuberculum, known to be dopaminergic, send ascending projections to the ventral telencephalon and prominent descending projections to vocal-acoustic integration sites, notably the hindbrain octavolateralis efferent nucleus, as well as onto the base of hair cells in the saccule via nerve VIII. Neurobiotin backfills of the vocal nerve in combination with TH-ir revealed CA terminals on all components of the vocal pattern generator, which appears to largely originate from local TH-ir neurons but may include input from diencephalic projections as well. This study provides strong neuroanatomical evidence that catecholamines are important modulators of both auditory and vocal circuitry and acoustic-driven social behavior in midshipman fish. This demonstration of TH-ir terminals in the main end organ of hearing in a nonmammalian vertebrate suggests a conserved and important anatomical and functional role for dopamine in normal audition.
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Affiliation(s)
- Paul M. Forlano
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
- Programs in Neuroscience, Ecology, Evolutionary Biology and Behavior, and Behavioral and Cognitive Neuroscience, The Graduate Center, City University of New York, Brooklyn, NY 11210
- Aquatic Research and Environmental Assessment Center, Brooklyn College, Brooklyn, NY
- Marine Biological Laboratory, Woods Hole, MA 02543
| | - Spencer D. Kim
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
| | - Zuzanna M. Krzyminska
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, NY 11210
| | - Joseph A. Sisneros
- Departments of Psychology and Biology, University of Washington, Seattle, WA, 98195
- Virginia Merrill Bloedel Hearing Research Center, Seattle
- Marine Biological Laboratory, Woods Hole, MA 02543
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11
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Remage-Healey L. Frank Beach Award Winner: Steroids as neuromodulators of brain circuits and behavior. Horm Behav 2014; 66:552-60. [PMID: 25110187 PMCID: PMC4180446 DOI: 10.1016/j.yhbeh.2014.07.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/30/2014] [Accepted: 07/31/2014] [Indexed: 11/27/2022]
Abstract
Neurons communicate primarily via action potentials that transmit information on the timescale of milliseconds. Neurons also integrate information via alterations in gene transcription and protein translation that are sustained for hours to days after initiation. Positioned between these two signaling timescales are the minute-by-minute actions of neuromodulators. Over the course of minutes, the classical neuromodulators (such as serotonin, dopamine, octopamine, and norepinephrine) can alter and/or stabilize neural circuit patterning as well as behavioral states. Neuromodulators allow many flexible outputs from neural circuits and can encode information content into the firing state of neural networks. The idea that steroid molecules can operate as genuine behavioral neuromodulators - synthesized by and acting within brain circuits on a minute-by-minute timescale - has gained traction in recent years. Evidence for brain steroid synthesis at synaptic terminals has converged with evidence for the rapid actions of brain-derived steroids on neural circuits and behavior. The general principle emerging from this work is that the production of steroid hormones within brain circuits can alter their functional connectivity and shift sensory representations by enhancing their information coding. Steroids produced in the brain can therefore change the information content of neuronal networks to rapidly modulate sensory experience and sensorimotor functions.
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Affiliation(s)
- Luke Remage-Healey
- Neuroscience and Behavior Program, Center for Neuroendocrine Studies, Department of Psychological and Brain Sciences, University of Massachusetts Amherst, 01003, USA.
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Goebrecht GKE, Kowtoniuk RA, Kelly BG, Kittelberger JM. Sexually-dimorphic expression of tyrosine hydroxylase immunoreactivity in the brain of a vocal teleost fish (Porichthys notatus). J Chem Neuroanat 2014; 56:13-34. [PMID: 24418093 DOI: 10.1016/j.jchemneu.2014.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 01/04/2014] [Accepted: 01/04/2014] [Indexed: 12/23/2022]
Abstract
Vocal communication has emerged as a powerful model for the study of neural mechanisms of social behavior. Modulatory neurochemicals postulated to play a central role in social behavior, related to motivation, arousal, incentive and reward, include the catecholamines, particularly dopamine and noradrenaline. Many questions remain regarding the functional mechanisms by which these modulators interact with sensory and motor systems. Here, we begin to address these questions in a model system for vocal and social behavior, the plainfin midshipman fish (Porichthys notatus). We mapped the distribution of immunoreactivity for the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH) in the midshipman brain. The general pattern of TH(+) cell groups in midshipman appears to be highly conserved with other teleost fish, with a few exceptions, including the apparent absence of pretectal catecholamine cells. Many components of the midshipman vocal and auditory systems were innervated by TH(+) fibers and terminals, including portions of the subpallial area ventralis, the preoptic complex, and the anterior hypothalamus, the midbrain periaqueductal gray and torus semicircularis, several hindbrain auditory nuclei, and parts of the hindbrain vocal pattern generator. These areas thus represent potential sites for catecholamine modulation of vocal and/or auditory behavior. To begin to test functionally whether catecholamines modulate vocal social behaviors, we hypothesized that male and female midshipman, which are sexually dimorphic in both their vocal-motor repertoires and in their responses to hearing conspecific vocalizations, should exhibit sexually dimorphic expression of TH immunoreactivity in their vocal and/or auditory systems. We used quantitative immunohistochemical techniques to test this hypothesis across a number of brain areas. We found significantly higher levels of TH expression in male midshipman relative to females in the TH cell population in the paraventricular organ of the diencephalon and in the TH-innervated torus semicircularis, the main teleost midbrain auditory structure. The torus semicircularis has been implicated in sexually dimorphic behavioral responses to conspecific vocalizations. Our data thus support the general idea that catecholamines modulate vocal and auditory processing in midshipman, and the specific hypothesis that they shape sexually dimorphic auditory responses in the auditory midbrain.
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Affiliation(s)
- Geraldine K E Goebrecht
- Department of Biology, Gettysburg College, 300 North Washington Street, Gettysburg, PA 17325, USA.
| | - Robert A Kowtoniuk
- Department of Biology, Gettysburg College, 300 North Washington Street, Gettysburg, PA 17325, USA.
| | - Brenda G Kelly
- Department of Biology, Gettysburg College, 300 North Washington Street, Gettysburg, PA 17325, USA.
| | - J Matthew Kittelberger
- Department of Biology, Gettysburg College, 300 North Washington Street, Gettysburg, PA 17325, USA.
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Abstract
Across animals, there is remarkable diversity in behavior. Modern genomic approaches have made it possible to identify the molecular underpinnings of varied behavioral phenotypes. By examining species with plastic phenotypes we have begun to understand the dynamic and flexible nature of neural transcriptomes and identified gene modules associated with variation in social and reproductive behaviors in diverse species. Importantly, it is becoming increasingly clear that some candidate genes and gene networks are involved in complex social behaviors across even divergent species, yet few comparative transcriptomics studies have been conducted that examine a specific behavior across species. We discuss the implications of a range of important and insightful studies that have increased our understanding of the neurogenomics of behavioral plasticity. Despite its successes, behavioral genomics has been criticized for its lack of hypotheses and causative insights. We propose here a novel avenue to overcome some of these short-comings by complementing "forward genomics" studies (i.e., from phenotype to behaviorally relevant gene modules) with a "reverse genomics" approach (i.e., manipulating novel gene modules to examine effects on behavior, hormones, and the genome itself) to examine the functional causes and consequences of differential gene expression patterns. We discuss how several established approaches (such as pharmacological manipulations of a novel candidate pathway, fine scale mapping of novel candidate gene expression in the brain, or identifying direct targets of a novel transcription factor of interest) can be used in combination with the analysis of the accompanying neurogenomic responses to reveal unexpected biological processes. The integration of forward and reverse genomics will move the field beyond statistical associations and yield great insights into the neural and molecular control of social behavior and its evolution.
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Hanson JL, Hurley LM. Context-dependent fluctuation of serotonin in the auditory midbrain: the influence of sex, reproductive state and experience. ACTA ACUST UNITED AC 2013; 217:526-35. [PMID: 24198252 DOI: 10.1242/jeb.087627] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In the face of changing behavioral situations, plasticity of sensory systems can be a valuable mechanism to facilitate appropriate behavioral responses. In the auditory system, the neurotransmitter serotonin is an important messenger for context-dependent regulation because it is sensitive to both external events and internal state, and it modulates neural activity. In male mice, serotonin increases in the auditory midbrain region, the inferior colliculus (IC), in response to changes in behavioral context such as restriction stress and social contact. Female mice have not been measured in similar contexts, although the serotonergic system is sexually dimorphic in many ways. In the present study, we investigated the effects of sex, experience and estrous state on the fluctuation of serotonin in the IC across contexts, as well as potential relationships between behavior and serotonin. Contrary to our expectation, there were no sex differences in increases of serotonin in response to a restriction stimulus. Both sexes had larger increases in second exposures, suggesting experience plays a role in serotonergic release in the IC. In females, serotonin increased during both restriction and interactions with males; however, the increase was more rapid during restriction. There was no effect of female estrous phase on the serotonergic change for either context, but serotonin was related to behavioral activity in females interacting with males. These results show that changes in behavioral context induce increases in serotonin in the IC by a mechanism that appears to be uninfluenced by sex or estrous state, but may depend on experience and behavioral activity.
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Affiliation(s)
- Jessica L Hanson
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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