Symposium
The neurobiology of dynamic innate social behaviors
シンポジウム
動的な社会性行動の神経生物学 |
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| 7月27日（土）16:34～17:03 第3会場（朱鷺メッセ 2F メインホールB）
3S03e-1
異なる社会性行動を司る2つの辺縁-視床下部回路
Takashi Yamaguchi（山口 隆司），Dayu Lin（林 大宇）
Neurosci Inst, New York Univ. Sch. of Medicine, New York, USA
The hypothalamus plays center roles in socio-innate behaviors across species including human beings; especially ventromedial hypothalamus ventrolateral area (VMHvl) and medial preoptic area (MPOA) function as aggression and sex loci, respectively. However, little is known about the circuits that direct control aggression and sex loci. Here, we will propose a circuit named "the dichotomic regulation circuit", wherein aggressive and sexual behaviors are modulated through direct excitatory control of a neural locus in a segregated input manner. Recently, we found that the posterior amygdala (PA), a subnucleus of the limbic areas, directly sends the excitatory projection into the MPOA and VMHvl, and distinct subpopulations in the PA innervate the MPOA and VMHvl. Due to the dense expression of sex hormone receptors and strong projections to other limbic and hypothalamic nuclei, the PA projection pathway has been implicated in the control of socio-innate behaviors. However, the functional role of the PA in socio-innate behaviors is still unclear. Based on our findings, we hypothesize that PA projection subpopulations control distinct socio-innate behaviors through driving hypothalamic activity and regulate distinct social behaviors via differential transcriptional expression of neuromodulatory genes and receptors. Confirming the hypothesis, we have identified the functional differentiation between PA-MPOA and -VMHvl pathways in socio-innate behaviors with pathway-specific recording and manipulation. We also performed RNA-Seq analyses to characterize the transcriptional profiles in this limbic-hypothalamic pathway. Furthermore, we try to validate the potential neuromodulatory control of aggression and sex beyond cell type characterization and circuit mapping. | | 7月27日（土）17:03～17:32 第3会場（朱鷺メッセ 2F メインホールB）
3S03e-2
免疫系と攻撃行動の相互作用
Aki Takahashi（高橋 阿貴）
筑波大行動神経内分泌学研究室
Aggressive behavior is adaptive behavior for animals to protect and obtain territory, mate, and offspring, and thus this behavior is conserved in many animal species. At the same time, there are large individual difference in aggression within a species, and some animals show high level of aggression whereas some animals rarely show aggressive behavior at all. Increasing evidence has shown the role of immune-related molecules in individual difference of aggression, and there are correlations between the level of cytokines in the periphery or central nervous system and aggression trait in several animal species including humans. Thus we aimed to understand neurobiological mechanism of this interplay between immune system and aggressive behavior using mouse model. Like humans, outbred CD-1 male mice show individual differences in aggression with most of mice exhibiting a spectrum of aggressive behavior but about 20% of mice showing no aggressive behavior. We found that there are a phasic increase of peripheral cytokines during aggressive encounter in both aggressive and non-aggressive individuals in a similar manner. By contrast, non-aggressive individuals showed higher elevation of central interleukin 1β (IL-1β) in the dorsal raphe nucleus compared to aggressive individuals. Pharmacological antagonism and gene knockdown of the receptors for IL-1 receptor in the DRN caused an increase in aggressive behavior, suggesting inhibitory role of IL-1β in the DRN on aggression. Our result indicated that physiological level of IL-1β has neuromodulatory role in the dorsal raphe nucleus, and produces individual difference of aggressive behavior in male mice. | | 7月27日（土）17:32～18:01 第3会場（朱鷺メッセ 2F メインホールB）
3S03e-3
Hypothalamic control of aggressive motivation and action
Annegret L Falkner（Falkner Annegret L）
Princeton Neuroscience Institute, Princeton University
Acts of aggression may be preceded by a motivated appetitive state that promotes animals to seek out opportunities for violence. While significant progress has been made identifying specific neural circuits that are involved in generating aggressive action, it has been more difficult to assess the neural mechanisms of these underlying proactive seeking states. Within the hypothalamus, a highly conserved subregion the VMHvl within the “social decision-making network”, is critical for intermale aggression. Stimulation of this area promotes attack and individual neurons in this area are active during aggressive action. In addition, we have recently found that this area is also critical for appetitive aggression-seeking behavior. Using an aggression-operant task, where male mice can proactively choose to seek out brief and repeated attack opportunities, we find that single neurons in the VMHvl respond during this aggression-seeking phase in addition to the action phase, and changes in population activity recorded optically using fiber photometry track changes in task learning and extinction. Optogenetic stimulation increases appetitive aggression by accelerating trial-to-trial response initiation latency. In addition, we find a new role for an anatomically segregated population of hypothalamic inhibitory neurons on the lateral edge of the VMHvl (the VMHvl “shell”). These neurons send strong direct inhibitory drive to the VMHvl and behave as a permissive gate during aggression seeking. Together these data suggest that this fundamental neural circuit serves to link together the motivation and action phases of aggression. | | 7月27日（土）18:01～18:30 第3会場（朱鷺メッセ 2F メインホールB）
3S03e-4
齧歯類および霊長類における各種子育て行動の実験的観察手法
Kumi O. Kuroda（黒田 公美）
理化学研究所 脳神経科学研究センター 親和性社会行動研究チーム
Mammalian parents provide extensive care for their young, including nursing (provision of maternal milk), nest building, transport, and protection from environmental hazards. Infants in return exhibit various attachment behaviors, such as remembering, following and clinging to the attachment figure, crying and the Transport Response (calming response during parental transport), in order to initiate and maintain the parental proximity. These parental and filial behaviors are part of most basic functions of living organisms, reproduction and survival respectively, so that have been studied extensively for their ultimate causation in evolutionary biology. Their proximate causation, namely the exact brain mechanisms of parental and filial behaviors, still remain to be clarified for the most part.
To understand the proximate causation of behaviors, it is crucial to establish the experimental assays to characterize and quantify the behavioral variables. However, the parent-offspring interactions are composed of numerous swift actions and responses, dynamically changing along with offspring growth. Therefore it is not easy to experimentally segregate each variable from the others. Moreover, despite of striking similarities of parent-offspring interactions among mammalian species from mice to humans, attention and efforts have not been taken enough to create experimental assays to be able to directly compare homologous behaviors in different species, hindering the cross-species interpretation of available findings. In this presentation, I would like to introduce some of our recent works to fill these gaps and implement comparative behavioral experiments in mice, common marmosets and humans. | |
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