Seminar: 9/8 - Brad Postle
11:00 to 12:30 PM at:
Department of Psychology and Neuroscience Training Program
University of Wisconsin
"Working Memory as an Emergent Property of Mind and Brain"
I will review the results of human behavioral, neuropsychological, neuroimaging (fMRI), and neurodisruptive (rTMS) studies that are consistent with the view that the short-term retention of information is supported by sustained activity in the same brain regions that are responsible for the processing and representation of this information in non-working memory situations, such as perception, semantic memory, oculo- and skeletomotor control, and speech comprehension and production. Notably, prefrontal cortex (PFC) is not among these regions. This emergent processes account overlaps with the idea that working memory storage is accomplished via the "temporary activation of long-term memory representations". Objections have been raised that models such as this, that do not postulate specialized working memory systems, cannot account for some of the core properties of working memory, such as its flexibility, its ability to represent ordinal position (e.g., sequences), and its ability to represent the subjective present. It will be demonstrated, however, that these concerns can be addressed by a second principle -- multiple encoding -- and behavioral and fMRI evidence for multiple encoding in working memory will be reviewed. Finally, the talk will address an important question about the PFC: If not storage, what are alternative explanations of delay period activity in this region?