Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), Córdoba, Argentina; Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Instituto de Ciencia y Tecnología de los Alimentos (ICTA), Córdoba, Argentina; Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitario Trindade, Trindade, 88040900, Florianópolis, SC, Brazil.
Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitario Trindade, Trindade, 88040900, Florianópolis, SC, Brazil.
Behav Brain Res. 2019 Jul 23;367:221-229. doi: 10.1016/j.bbr.2019.04.003. Epub 2019 Apr 3.
It is well known that during a social conflict, interactions are dependent on the animal's propensity to behave aggressively as well as the behavior of the opponent. However, discriminating between these two confounding factors was difficult. Recently, a Social Interaction (SI) test using photocastrated males as non-aggressive stimuli was proposed as a useful tool to evaluate aggressiveness. The avian Intercollicular- Griseum centralis complex (comparable to mammalian periaqueductal gray) has been reported as a crucial node in the descending pathways that organize behavioral and autonomic aspects of defensive responses and aggressiveness. Herein, using the SI test, we evaluated whether mesencephalic areas are activated (expressed c-fos) when photostimulated adult males are confronted with non-responsive (non-aggressive) opponents. Furthermore, we also examined whether mesencephalic activation is related to male performance during the SI test (i.e., aggressive vs. non-aggressive males) in birds reared in enriched or in standard environments. Five mesencephalic areas at two anatomic levels (intermediate and rostral) and locomotion during SI testing were studied. Aggressive males showed increased c-fos expression in all areas studied, and moved at faster speeds in comparison to their non-aggressive and control counterparts. Non-aggressive males and the test controls showed similar c-fos labeling. In general, rearing condition did not appear to influence c-fos expression nor behavior during the SI test. Findings suggest that mesencephalic activation is involved when males are actively expressing aggressive behaviors. This overall phenomenon is shown regardless of both the environmental stimuli provided during the birds´ rearing and the potentially stressful stimuli during the SI trial.
众所周知，在社会冲突中，互动取决于动物表现出攻击性的倾向以及对手的行为。然而，区分这两个混杂因素是困难的。最近，提出了一种使用去势雄性作为非攻击性刺激的社交互动（SI）测试，作为评估攻击性的有用工具。鸟类的中脑间脑灰结节复合体（相当于哺乳动物的导水管周围灰质）已被报道为组织防御反应和攻击性的行为和自主方面的下行途径中的关键节点。在此，我们使用 SI 测试评估当成年雄性受到非反应性（非攻击性）对手的刺激时，中脑区域是否被激活（表达 c-fos）。此外，我们还研究了中脑激活是否与在丰富或标准环境中饲养的鸟类的 SI 测试中的雄性表现（即攻击性与非攻击性雄性）有关。在两个解剖水平（中间和额状）研究了五个中脑区域和 SI 测试期间的运动。攻击性雄性在所有研究区域均显示出 c-fos 表达增加，并且与非攻击性和对照雄性相比，移动速度更快。非攻击性雄性和测试对照表现出相似的 c-fos 标记。一般来说，饲养条件似乎不会影响 SI 测试期间的 c-fos 表达或行为。研究结果表明，中脑激活涉及雄性积极表达攻击性行为时。这种整体现象显示，无论在鸟类饲养期间提供的环境刺激如何，以及在 SI 试验期间的潜在压力刺激如何。
