Context shift and protein synthesis inhibition disrupt long-term habituation after spaced, but not massed training in the crab Chasmagnathus.

HERMITTE G., PEDREIRA E., TOMSIC D. AND MALDONADO H.

NEUROBIOLOGY OF LEARNING AND MEMORY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 1999 vol. 71 p. 34 - 49

1074-7427

AbstractAn opaque screen moving overhead elicits an escape response in the crabChasmagnathusthat 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 ìg) 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.