Shared component processes in working memory and long-term memory : Insights from functional brain imaging

Sammanfattning: Marklund, P. (2004). Shared component processes in working memory and long-term memory: Insights from functional brain imaging. Department of Psychology, Umeå University, S-901 87 Umeå SwedenRecent findings from functional neuroimaging studies have shown pronounced similarities in the functional brain activity patterns associated with tests of various cognitive functions. This thesis investigates shared component processes in working memory and declarative long-term memory. Study 1 showed a common pattern of increased activity in four anatomically distinct regions in prefrontal cortex during three tests each of working memory, episodic memory, and semantic memory. Such similarities may reflect shared demands on working-memory processes across all tests or increased demands on attentional mechanisms. Study 2 was designed to dissociate these possibilities by measuring sustained and transient brain activity during tests of working memory, long-term memory and sustained attention. The results provided support for the notion that one basis for overlapping activations is increased attentional demands, but some activity seems to reflect cognitive control related to mnemonic processes. Taken together, the results indicate that it is critical for taxonomies of cognitive functions to consider similarities in underlying cognitive and associated neurobiological component processes.