背景:在社会背景下,个人能够检测来自他人的外部信息,并根据情况协调行为反应,一种叫做社会决策的现象。社会决策是多方面的,受情绪和动机因素如压力的影响,疾病,和饥饿。然而,动机状态竞争和相互作用的神经生物学基础尚不清楚。
目的:我们在社会情感偏好(SAP)测试中研究了内部状态可能影响社会行为的神经机制。在SAP测试中,实验大鼠选择与幼稚或应激性个体相互作用,表现出与应激性幼年个体相互作用的年龄依赖性偏好,但避免强调成人的特性。首先,我们评估了食物和水剥夺对SAP行为的影响。SAP测试中的行为需要岛状皮层,它接受来自下丘脑外侧(LH)的摄入相关肽黑色素浓缩激素(MCH)和食欲素神经元的输入。本研究旨在评估LH和岛状MCH和食欲素在SAP测试中的作用。
方法:SAP试验在大鼠中进行,食物和水被剥夺或在剥夺14小时后允许1小时获得食物和水(缓解状况)。在SAP测试或社交互动测试之前,单独的成组大鼠接受了套管植入物,用于微量注射药物以抑制LH或阻断或刺激脑岛中的MCH或食欲素受体。
结果:在对幼年大鼠进行SAP测试之前,食物和水的剥夺导致偏好从压力较大的大鼠转向幼稚的幼年。用麝香酚(100ng/side)对LH的药理抑制作用消除了对青少年应激的特异性,以及对成人幼稚的偏好。用SNAP94847(50μM)或TCS1102(1μM)阻断岛叶皮质中的MCH受体1或食欲素受体,分别,还废除了对强调青少年特定的偏好,但是只有食欲素受体的拮抗作用才能消除对成人幼稚同种异体的偏爱。在岛叶皮层中微量注射增加剂量(50或500nM)的MCH或orexin-A会增加与少年物种的一对一社交互动测试中的相互作用时间;但是,只有微量注射食欲素-A增加了与成人幼稚物种的相互作用时间。
结论:综合来看,这些结果表明,下丘脑外侧肽通过岛叶皮层中的MCH和食欲素神经传递的作用来塑造社会接近或回避的方向。
BACKGROUND: In a social context, individuals are able to detect external information from others and coordinate behavioral responses according to the situation, a phenomenon called social decision-making. Social decision-making is multifaceted, influenced by emotional and motivational factors like stress, sickness, and hunger. However, the neurobiological basis for motivational state competition and interaction is not well known.
OBJECTIVE: We investigated possible neural mechanisms through which internal states could shape social behavior in a social affective preference (SAP) test. In the SAP test, experimental rats given a choice to interact with naïve or stressed conspecifics exhibit an age-dependent preference to interact with stressed juvenile conspecifics, but avoid stressed adult conspecifics. First, we assessed the effect of food and water deprivation on SAP behavior. Behavior in the SAP test requires the insular cortex, which receives input from the ingestion-related peptides melanin-concentrating hormone (MCH) and orexin neurons of the lateral hypothalamus (LH). This study aimed to evaluate the role of LH and insular MCH and orexin in SAP test.
METHODS: SAP tests were conducted in rats that were sated, food and water deprived or allowed 1 h of access to food and water after 14 h of deprivation (relieved condition). Separate cohorts of sated rats received cannula implants for microinjection of drugs to inhibit the LH or to block or stimulate MCH or orexin receptors in the insula prior to SAP tests or social interaction tests.
RESULTS: Food and water deprivation prior to SAP tests with juvenile rats caused a shift in preference away from the stressed rat toward the naïve juveniles. Pharmacological inhibition of LH with muscimol (100 ng/side) abolished the preference for the juvenile-stressed conspecific, as well as the preference for the adult naïve conspecific. The blockade of MCH receptor 1or orexin receptors in the insular cortex with SNAP94847 (50 μM) or TCS1102 (1 μM), respectively, also abolished the preference for the stressed juvenile conspecific, but only the antagonism of orexin receptors was able to abolish the preference for the adult naïve conspecific. Microinjection of increasing doses (50 or 500 nM) of MCH or orexin-A in the insular cortex increased the interaction time in the one-on-one social interaction test with juvenile conspecifics; however, only the microinjection of orexin-A increased the interaction time with adult naïve conspecifics.
CONCLUSIONS: Taken together, these results suggest that lateral hypothalamus peptides shape the direction of social approach or avoidance via actions MCH and orexin neurotransmission in the insular cortex.