Hippocampus damage results in severe anterograde amnesia associated with a partial (2-3 years) retrograde amnesia. This observation suggests a long-term consolidation process lasting 2-3 years. Hippocampal asymmetry has been established, and in cases of left hippocampal lesions amnesia is more language-related, whereas in cases of right damage, a more nonverbal amnesia is found. According to the brain functional imaging studies, the hippocampus participates in a wide variety of memory processes, including: working memory, semantic memory, episodic memory, and memory retrieval. Hippocampus becomes also active in some emotional conditions (e.g., disgust, unpleasant/fearful stimuli, facial emotional perception, etc.); in these last cases usually the amygdala and other brain structures are also involved. Interestingly, the hippocampus is also related with “novelty discrimination” and “detection of deviant stimuli”. Some authors have even suggested that this is a primary function of the hippocampus: a kind of comparator that determines whether the current information is new (and should be stored in memory), or it is old (and no storage is necessary). The “anticipatory” function of the hippocampus reported in some studies, such as “anticipating regret”, “relational processing during elaboration of future events” and “future event construction,” is intriguing. In this anticipatory function prefrontal cortex is also involved, and hippocampal participation may suggest the use of memories as kind of templates used to anticipate future events.
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