| A decade of studies on long-term habituation (LTH) in the crab Chasmagnathus is reviewed. Upon sudden presentation of a passing object overhead, the crab reacts with an escape response that habituates promptly and for at least five days. LTH proved to be an instance of associative memory and showed context, stimulus frequency and circadian phase specificity. A strong training protocol (STP) (<FONT FACE="Symbol">³</font>15 trials, intertrial interval (ITI) of 171 s) invariably yielded LTH, while a weak training protocol (WTP) (<FONT FACE="Symbol">£</font>10 trials, ITI = 171 s) invariably failed. STP was used with a presumably amnestic agent and WTP with a presumably hypermnestic agent. Remarkably, systemic administration of low... |
