Learning Objectives

This chapter considers the brain regions associated with long-term memory, a type of explicit memory (see Chapter 1). Long-term memory can be broken down into episodic memory and semantic memory. Episodic memory refers to the detailed retrieval of a previous episode, such as when someone remembers a happy moment of his or her life. Semantic memory refers to the retrieval of factual information, such as the definition of a word or the name of the current president. Semantic memories are formed through repeated exposure to information throughout life and lack the details associated with episodic memories. This information is simply known and there is no memory for the previous details of the learning experience. Although episodic memory and semantic memory both refer to conscious forms of retrieval, the degree of detail and subjective experience associated with these types of memory is quite different. It follows that the brain regions associated with episodic memory and semantic memory are also distinct. The first two sections of the chapter (sections 3.1 and 3.2) consider the brain regions associated with episodic memory and semantic memory. Section 3.3 will consider long-term memory consolidation (i.e., the process of creating more permanent memory representations in the brain). In section 3.4, the role of sleep in long-term memory consolidation is examined. Long-term memory consolidation requires the interaction between multiple brain regions in which activity oscillates at specific frequencies. In section 3.5, the brain regions associated with memory encoding will be reviewed.