ABSTRACT
The idea that learning and memory mechanisms of the brain involve activity-dependent synaptic plasticity gained widespread acceptance after the discovery of long-term potentiation (LTP) in the hippocampus (Bliss and Lomo, 1973), and its subsequent experimental analysis in the hippocampus and other brain regions (Bear and Kirkwood, 1993; Castro-Alamancos, Donoghue and Connors, 1995; Kirkwood et al., 1993; Smith 1987). The induction of hippocampal LTP requires repeated conjunctions of presynaptic and postsynaptic activity. This requirement for both presynaptic and postsynaptic activity can be termed a “twofactor rule” for synaptic modification.
