‘The Organization of Behavior’ [5], where he states “When an axon of cell A is near enough to excite cell B or repeatedly or consistently takes part in firing it, some growth or metabolic changes takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased”. Hebb also postulates that if two neurons are active at the same time, the synaptic efficiency of the appropriate synapse will be strengthened [5]. It took almost 25 years to discover a process by which strengthening of synaptic connections can be achieved, and the importance of one model that seemed to fit Hebb’s idea. This model is known as a long-term potentiation (LTP). Based on several groundbreaking studies, it has been conceptualized that, (1) LTP is an enhancement of synaptic efficiency that can be induced by high frequency, or by low frequency stimulation; (2) LTP can last for an extended period of time (from weeks to months) in vivo; (3) It is most prominent in regions of the brain that are strongly implicated in learning and memory (e.g. neocortex and hippocampus); (4) LTP is specific to tetanized inputs: the non-tetanized inputs are not potentiated; (5)
