D. Tomsic et al., AGE-RELATED DEFICITS OF LONG-TERM-MEMORY IN THE CRAB CHASMAGNATHUS, Journal of comparative physiology. A, Sensory, neural, and behavioral physiology, 178(1), 1996, pp. 139-146
Short- and long-term memory in adult crabs Chasmagnathus granulatus of
different age are evaluated in two learning paradigms: habituation to
a visual danger stimulus and appetitive conditioning. No difference b
etween young, middle-aged and aged animals is found in short-term habi
tuation with 15 training trials. A good level of retention of the habi
tuated response at 24 h is exhibited by young and middle-aged crabs bu
t a poor one by aged crabs. When the training-to-testing interval is l
engthened to 48 h or the training session reduced to 7 trials, young a
nd middle-aged crabs continue to show long-term habituation but aged i
ndividuals exhibit no retention at all. As regards appetitive conditio
ning, young, middle-aged and aged crabs present similar short-term mem
ory with 5 training trials and similar long-term memory when tested at
24 h, but an age-related deficit in long-term retention is exhibited
when the intersession interval is lengthened to 48 h or the training r
educed to 3 trials. Thus, a reduction of long-term memory related to a
ge is demonstrated in the crab Chasmagnathus. Since it is shown in two
different learning paradigms, the possibility of explaining the defic
it in terms of a failure in memory mechanisms due to aging rather than
as a consequence of ontogenetic shift in the crab's behavior is discu
ssed.