Effects of enhanced learning protocol on long-term memory components in the mollusk aplysia

The budgeting of defensive and appetitive behaviors triggered in response to aversive stimuli modulates an imperative learning process pertinent to both humans and animals alike (Shields-Johnson et al. 2013). Aplysia possesses similar, yet simplified neural networks to humans, presenting a unique opportunity to expand the knowledge about long-term memory (LTM) formation (Kandel, 2001) and even manipulate the methods of administration at a behavioral level to possibly maximize LTM (Zhang et al. 2012). A standard aversive training protocol, consisting of trials of electric stimuli delivered at a constant 30-min inter-trial interval (ITI), is known to induce two behavioral modifications at 24, but not at 72 hours: long-term sensitization (LTS), which manifests as enhancement of defensive reflexes, and long-term feeding suppression (LTFS, Shields-Johnson et al. 2013). An enhanced learning protocol (ELP), derived from a computational algorithm based on a biochemical model with variable ITIs (10, 10, 5, 30 min), is known to induce an augmented LTS lasting for several days (Zhang et al. 2012). Because the effects of ELP on LTFS remains unknown, this project aimed to determine if this method of training enhances LTM by prolonging not only LTS, but also LTFS. Defensive reflexes and feeding were measured before and 24, 38, 48, 62, and 72 hours after ELP delivery, while untrained animals were used as controls. Data was analyzed with two-way repeated measures ANOVA followed by Fisher LSD tests. Although preliminary, the results of this study indicate the presence of LTFS at all time points, and even showed a trend of an increase in LTFS as time progressed. Data on defensive reflexes demonstrate a trend attributable to LTS formation, corroborating the findings of Zhang et al. (2012). Current data suggest that the ELP prolongs LTM duration and therefore exhibits encouraging evidence of a paramount learning method that may enhance LTM.