Working memory in another dimension: Functional imaging of human olfactoryworking memory

The majority of working memory research has been carried out within the vis ual and auditory modalities, leaving it unclear how other modalities would map onto currently proposed working memory models. In this study we examine d the previously uninvestigated area of olfactory working memory. Our aim w as to investigate if olfactory working memory would engage,prefrontal regio ns known to be involved in working memory for other sensory modalities. Usi ng positron emission, tomography we measured cerebral blood flow changes in 12 volunteers during an olfactory working memory task and a comparison vis ual working memory task. Our findings indicate that both olfactory and face working memory engaged dorsolateral and ventrolateral frontal cortex when the task requirements were matched; a conjunction analysis indicated overla p in the distribution of activity in the two tasks. Similarities and differ ences in activity were noted in parietal lobe regions, with both tasks enga ging inferior areas of 40/7, but only visual working memory showing increas ed activity within left superior parietal cortex. The findings support the idea that working memory processes engage frontal cortical areas independen t of the modality of input, but do not rule out the possibility of modality -specific neural populations within dorsolateral or ventrolateral cortex. ( C) 2001 Academic Press.