Krasne F B, Shamsian A, Kulkarni R
Department of Psychology and Brain-Research Institute, University of California at Los Angeles 90095-1563, USA.
J Neurosci. 1997 Jan 15;17(2):709-16. doi: 10.1523/JNEUROSCI.17-02-00709.1997.
The excitability of the lateral giant escape reflex of socially dominant and submissive crayfish at rest and during agonistic encounters was studied and compared. During agonistic encounters the excitability of the lateral giant reflex falls, substantially in subordinates and slightly in dominants, whereas at rest excitability seems to be independent of social status. Thus, paradoxically, socially dominant animals are more likely to execute lateral giant escape reactions during interactions than are subordinates. It is suggested that subordinates under threat of attack tend to engage circuitry involved in flexible, nonreflex ("voluntary") types of escape not mediated by giant neurons and therefore inhibit giant neuron-mediated reflex circuitry that produces prompt, but less adaptive, responses. In contrast, dominants go about their business, mainly ignoring their conspecifics and relying on reflex escape to protect them from unexpected attack. Consistent with this view, escape of subordinates during agonistic encounters is mediated by nongiant, not reflex, circuitry. These observations and their interpretation suggest a possible functional role for recently described social status-dependent serotonergic modulation of the lateral giant reflex, which is inhibitory in sign in subordinates and facilitatory in dominants.
对处于静止状态以及在争斗相遇期间社会地位占主导和从属的小龙虾的外侧巨逃逸反射的兴奋性进行了研究和比较。在争斗相遇期间，外侧巨反射的兴奋性下降，从属个体下降幅度大，占主导个体下降幅度小，而在静止状态下，兴奋性似乎与社会地位无关。因此，矛盾的是，在互动过程中，社会地位占主导的动物比从属动物更有可能执行外侧巨逃逸反应。有人认为，受到攻击威胁的从属个体倾向于启用涉及灵活的、非反射性（“自愿”）逃逸类型的神经回路，这些逃逸不由巨神经元介导，因此会抑制由巨神经元介导的产生迅速但适应性较差反应的反射神经回路。相比之下，占主导地位的个体则各行其是，主要无视同种个体，并依靠反射逃逸来保护自己免受意外攻击。与此观点一致的是，从属个体在争斗相遇期间的逃逸是由非巨神经元而非反射性神经回路介导的。这些观察结果及其解释表明，最近描述的外侧巨反射的社会地位依赖性5-羟色胺能调节可能具有功能性作用，其在从属个体中为抑制性，在占主导个体中为促进性。
