社会行動 2
Social Behavior 2
O2-8-2-1
メスマウス視床下部腹内側核における社会行動に関連したニューロン活動:生殖周期の影響
Social signals in the ventromedial hypothalamus of female mice: influence of the reproductive cycle

○野元謙作1
○Kensaku Nomoto1, Susana Q. Lima1
シャンパリモー神経科学プログラム・ポルトガル1
Champalimaud Neuroscience Programme, Lisbon, Portugal1

Choosing the right actions at the proper time is crucial for animals to survive, especially during social interactions. One such example is reproductive behavior in female rodents. When a male attempts to mount a female, she refuses the mounting attempts if she is not in the fertile phase of the reproductive cycle. By contrast, when fertile, she displays a receptive posture permitting copulation. Although this behavioral switch has long been described, very little is known regarding the neural mechanisms underlying it.
To address this issue, we performed extracellular single-unit recordings from freely behaving female mice across the reproductive cycle. We targeted the ventrolateral region of the ventromedial hypothalamus (VMHvl) as the recording site. First, the VMHvl is involved in the control of social behavior between conspecifics such as male aggression and female sexual behavior. Second, the VMHvl has access to olfactory information, which is important for rodent social behavior. Third, the VMHvl has rich expression of receptors for sex hormone, thereby it can mediate behavioral changes across the reproductive cycle.
In the present behavioral assay, the test female was allowed to freely interact with the stimulus animals, while the activity of VMHvl neurons was recorded. The stimulus animal was either a female or a male. In agreement with a previous study in male mice, we found VMHvl neurons whose activity was gender specific. Many neurons showed sustained activity changes in response to the stimulus animals, while some neurons responded to specific behavioral events (e.g., sniffing anogenital area of a female mouse). Furthermore, we found that the proportion of male-responsive neurons during the most sexually receptive phase was higher than those during the other phases. These preliminary results suggest that increased neuronal responsiveness may underlie behavioral changes across the reproductive cycle.
O2-8-2-2
Tissue plasminogen activatorは社会的不安を制御する
Tissue-type plasminogen activator modulates social anxiety

○三井真一1,2, 中村和希2, 高部歩美2, 清水芙紀2, 岡田清孝3, 松尾理4
○Shinichi Mitsui1,2, Kazuki Nakamura2, Ayumi Takabe2, Fuki Shimizu2, Kiyotaka Okada3, Osamu Matsuo4
群馬大院・保健学・リハビリ1, 群馬大・医・作業療法2, 近畿大・医・再生機能3, 近畿大・医4
Dept of Rehabilitation Sci, Grad Sch Health Sci, Gunma Univ, Maebashi, Japan1, Dept Occupational Therapy, Gunma Univ, Maebashi, Japan2, Dept Physiol Regenerative Med, Kinki Univ Facalty Med, Osakasayama, Japan3, Kinki Univ Faculty Med, Osakasayama, Japan4

Tissue-type plasminogen activator (tPA) is a serine protease, which was originally identified as a fibrinolytic enzyme, expressed by neuronal cells in various brain regions. Recent reports have suggested that tPA modulates various brain functions such as learning and memory, the rewarding effect of morphine, ethanol-withdrawal seizure. However, it is still obscure whether tPA participates in social behavior or not. We analyzed social behavior using tPA knockout (KO) and heterogenic (Het) mice. In a resident-intruder test, the latency to the first contact to a stimulator mouse was significantly prolonged in tPA KO mice than tPA Het mice. The time for active behavior (chasing, sniffing) by tPA KO mice was longer than that by tPA Het mice. In a 3-chamber test, at the first session, test mice were place at the center chamber which connected to two chambers containing an empty stainless cage and freely investigated for 10 min. TPA KO mice investigated empty cages as tPA Het mice did, suggesting normal anxiety. At the second session, in which a novel mouse (S1) was placed in a cage, tPA KO mice spent more time investigating S1 mouse than an empty cage as Het mice did. However, tPA KO mice significantly more frequently investigated an empty cage than Het mice did. Further, tPA KO mice walked significantly longer distance in the chamber containing an empty cage than tPA Het mice. At the third session, in which a novel mouse (S2) was placed in another empty cage, tPA KO mice, like tPA Het mice, spent more time investigating S2 mouse than S1 mouse. However, compared with tPA Het mice, tPA KO mice significantly more frequently investigated S1 mouse and moved longer distance in the chamber with S1 mouse cage. These results suggest that tPA deficiency enhances social anxiety but without affecting social interest.
O2-8-2-3
母親からの信号により、父親マウスは仔育てする
Displays of mouse pup retrieval as paternal parental behavior following communicative interaction with maternal mates

○東田陽博1, , 梁明坤1, 鐘静1, 馬文ショウ1, 横山茂1
○Haruhiro Higashida1, Shirin Akther1, Mingkun Liang1, Jing Zhong1, Wen-Jie Ma1, Shigeru Yokoyama1
金沢大・子どものこころの発達研究センター1
Res. Cent. Child Mental Dev, Univ of Kanazawa, Ishikawa1

According to Schor, "a stable, well-functioning family that consists of 2 parents and children is potentially the most secure, supportive, and nurturing environment in which children may be raised." In this, the role of the father is highly significant, and the physical absence of the father has been seen as the major problem facing families in the United States. The question then arises: what factors determine male parental care, and how may this be encouraged? At the neuroscientific level, this may be addressed by determining the molecular and neuronal basis of the male parental brain. Although a number of animal models have been used in experimental studies of parental care, in view of its value for genetic studies, a mouse model of paternal care could be especially useful. While some strains of the laboratory mouse Mus musculus become biparental, there is little information about what specifically induces male parental behavior. In the present study, we have addressed the above question regarding factors that determine male parental care using laboratory mice of the outbred ICR strain (originally obtained from the Charles River Laboratories in 1965 and since then bred in Japan; alternative name, Swiss CD1). The ICR mice are uniparental but a good model for parental behavior, because they very actively reproduce, and exhibit easily-monitored pup-retrieval after separation, which is a reliable indicator of parental behavior. We show that male ICR mice demonstrate robust parental care, which is induced by signaling from the mother, after separation from the pups. We show that this signaling is mediated through olfactory and auditory cues, and that the male response can be modified hormonally via oxytocin and through the central cholinergic system.
O2-8-2-4
Attachment Behavior in early infancy: Comparative Physiological Assessment of Transport Response (TR) in Human and Mouse
○Gianluca Esposito1, Sachine Yoshida1, Susumu Yokota2, Paola Venuti3, Shota Okabe4, Takefumi Kikusui4, Tadafumi Kato1, Kumi O. Kuroda1
RIKEN Brain Science Institute1, Department of Clinical Laboratory, Saitama Children's Medical Center, Saitama, Japan2, Department of Cognitive Science, University of Trento, Italy3, Companion Animal Research, School of Veterinary Medicine, Azabu University, Kanagawa, Japan4

Mother-infant interaction is the most critical social relationship for mammalian infants. The emergence of a strong bonding, assures the survival of the species, and influences the well-being of both mother and infant. To build this bonding, the infant as well as themother is equipped with complex physiological and behavioral patterns that encourage maternal proximity. Here we show how the infant calming response during maternal carrying is an early filial contribution and functions as a vital component for the mother-infant bonding conserved in mammals. In our study, we demonstrate that in both human and mice, acarried infant entered a coordinated calming state, involving rapid, reversible reductions in heart rate, vocalization, and movement. In the mouse model, the neural mechanism of the carried state involved tactile sensation, proprioception, parasympathetic activity, and cerebellar control. The burden of transporting a young (both in human and mice) is smoothed when the young shown specific behaviors (stop of distress vocalizations and voluntary movement). For this reason we speculate that TR is a specific set of responses that may have been selected and conserved in mammalian evolution, for the adaptive value such as in emergency escape of the mother-infant dyad. Finally, we discuss some clinical implication of the study describing the case of Autism Spectrum Disorders (ASD). Children with ASD show difficulty adapting their body posture to be easily held and do not shown decreasing of crying when they are hold. Our findings have implications for parenting theory and practice, and may provide clinical applications relevant to neuro-developmental disorders in early infancy.
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