Hermitte G, Pedreira M E, Tomsic D, Maldonado H
Laboratorio de Fisiologia del Comportamiento Animal, Facultad de Ciencias Exactas y Naturales, Departamento Biologia, Universidad de Buenos Aires, Buenos Aires, (1428), Argentina.
Neurobiol Learn Mem. 1999 Jan;71(1):34-49. doi: 10.1006/nlme.1998.3858.
An opaque screen moving overhead elicits an escape response in the crab Chasmagnathus that after a few presentations habituates for a long period (long-term habituation, LTH). Previous results suggested that spaced (15 trials separated by 171 s) and massed training (300 trials without rest interval) were correlated with two different memory components of LTH. The present experiments were aimed at further studying the mechanisms subserving these components. Results indicate that LTH acquired by spaced but not by massed training is blocked either by a training-to-testing context shift or by cycloheximide (15-25 microg) pre- or posttraining injection and that LTH after spaced training persists for longer time (5 days) than after massed training (2 days). A model based on these results that distinguishes two LTH-memory components is proposed: a (context-signal) LTH yielded by spaced training, dependent of context, sensitive to cycloheximide (CYX), and long lasting; and a (signal) LTH yielded by massed training, dependent only on the signal invariance, insensitive to CYX, and shorter lasting.
头顶上方移动的不透明屏幕会引发招潮蟹的逃避反应，经过几次呈现后，这种反应会在很长一段时间内产生习惯化（长期习惯化，LTH）。先前的结果表明，间隔训练（15次试验，间隔171秒）和集中训练（300次试验，无休息间隔）与LTH的两种不同记忆成分相关。本实验旨在进一步研究支持这些成分的机制。结果表明，间隔训练而非集中训练所获得的LTH，会因训练到测试的情境变化或训练前或训练后注射环己酰亚胺（15 - 25微克）而被阻断，并且间隔训练后的LTH持续时间（5天）比集中训练后的（2天）更长。基于这些结果，提出了一个区分两种LTH记忆成分的模型：间隔训练产生的（情境 - 信号）LTH，依赖于情境，对环己酰亚胺（CYX）敏感，且持续时间长；集中训练产生的（信号）LTH，仅依赖于信号不变性，对CYX不敏感，且持续时间短。
