Supporting the role of LTP, synaptic connections and plasticity in learning and memory functions, Scoville and Milner reported that bilateral medial temporal-lobe resection, including a structure called the hippocampus, causes a persistent impairment of recent memory [12]. These findings supported the hypothesis that the hippocampus is critically involved in the retention of current experience. What was striking about their study is that hippocampus-independent cognitive functions were preserved, and this aspect of preservation of certain cognitive functions in subjects with hippocampal lesions is supported in the famous patient H. M. [13]. For example, H. M.’ s language and reasoning abilities were unchanged, his performance on an IQ test was increased, and remote memories were intact. More recent anatomical studies of H. M., and other human patients with amnesic syndromes, as well as studies in animals, suggest that the memory deficits in H. M. arose most probably from damage to the hippocampus and cortical structures immediately surrounding the medial temporal lobe [14]. Follow up studies by Anderson and Lomo reported that a single, short test shock, following an initial period of conditioning
