Working Memory: Localized or Distributed?

Operational memory (the process of a transitory storing information -> recent memories) is essential for some of the human abilities, as the understanding of language and the deductive reasoning. The areas of the brain involved in the declarative memory (the memory for facts and events -> memories of the past) are well known (for example, the hypocampus), but those [areas] involved in the operational memory are not. A PET study (1) determined four metabolically active areas of the brain, during an operational memory (while performing tasks requiring the identification of spatial relationship among different points [?]). Four areas of the brain, all of them in the right hemisphere, became activated during this visual-spatial task: the frontal, the pre-motor, the parietal, and the occipital cortex. In another study, however, when the subjects executed the task of memorizing letters of the alphabet, areas of language on the left hemisphere were activated. These peculiar results in each specified assignment indicate the operational memory is a processes distributed [shared?] between different areas of the brain.

1. Nature, 363 (6430): 523-625 (1993)