From this paper, we can draw some interesting conclusions: <em>Aplysia</em> contains a CREB-like protein (this paper presents the first evidence of this), cAMP is involved in long-term facilitation, long-term facilitation requires protein synthesis (while short term facilitation does not), and <em>Aplysia</em> is a good model system for behavioral studies.  These conclusions make this an incredibly seminal paper in the field of neuroscience.