A Parallel Processing Hypothesis for Short-Term and Long-Term Memory in Aplysia.
Final technical rept. 1 May 95-30 Apr 96,
YALE UNIV NEW HAVEN CT DEPT OF PSYCHOLOGY
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Several lines of evidence support a parallel processing view for short- and long- term memory in Aplysia 1 The cellular analog of long-term memory, long-term synaptic facilitation LTF, can be induced by repeated applications of the neuromodulator serotonin 5HT in the complete absence of the analog of short-term memory, short-term facilitation STF. 2 STF and LTF can be dissociated by their temporal dynamics STF decays within 2 hours, whereas LTF does not begin to be expressed until 10-15 hours. 3 A novel stage of intermediate-term facilitation lTF seems to be a precondition to triggering the long-term process LTF. 4 It has long been known that spaced behavioral training typically produces superior memory compared to massed training. We observe a related phonemenon at the synaptic level 5 spaced applications of 511T induces STF, ITF and EF, whereas comparable exposure to 5HT at one time induces only STF and ITF no LTF is induced. Finally, at a behavioral level, we find that long-term memory for sensitization can be induced in the absence of short-term memory.