The neuropsychology of relationships between episodic and semantic memory

peer reviewedCognitive models of the organization of memory propose different conceptions of the relationships between episodic and semantic memory. In the present review, we consider two influential models. According to one model (Tulving, 1995), episodic and semantic memory are two functionally and anatomically distinct systems. Their relationships are referred to as “embeddedness”, that is, information must be encoded in semantic memory in order to achieve episodic memory. Another model (Squire & Zola, 1998) describes episodic and semantic memory as two subsystems of declarative memory. Both depend on the same brain region and should be impaired in amnesic patients. Furthermore, information is usually first encoded in episodic memory, before being transferred to semantic memory. In this review, we describe the neuropsychological data that support each model, as well as studies that contradict these models. Three sets of evidence are described. First, we consider recognition memory in amnesic patients. Recognition memory processes, recollection and familiarity, have been related to episodic and semantic memory, respectively (Tulving, 1995). Contradictory findings exist concerning the relative preservation of familiarity-based recognition in certain types of amnesic patients. Then we describe studies that have examined whether amnesic patients can learn new semantic information or not. Finally, episodic learning in semantic dementia is considered