Brain regions for spatial & non-spatial working memory
February 27 Science
National Institute of Mental Health (NIMH) scientists have pinpointed the part of the human brain that holds information momentarily about where things are located. This specialized circuitry for spatial working memory keeps track of, for example, the ever-changing locations of other cars while you're driving.
they scanned a total of 11 subjects while they performed various working memory and control tasks. The fMRI scanner tracks telltale signals emitted by oxygenated blood in a magnetic field to reveal what parts of the brain are active at any given moment.
While in the scanner, subjects were asked to remember either the locations or the identities of three faces flashed briefly in different spots on a computer screen. After a nine-second pause, during which the information was held in working memory, a face appeared somewhere on the screen for a few seconds. For the spatial working memory task, subjects pressed buttons to indicate whether this latter location was the same as one of the three they had seen previously. In trials testing non-spatial working memory, they similarly signaled whether the identity of the "test" face was the same as one of the three they had previously seen.
As hypothesized, the researchers saw high activity during an eye movement task in the middle upper part of the frontal cortex, confirming location of the frontal eye field. Also as predicted, just in front of this area they discovered a heretofore unknown, functionally distinct, region that showed sustained activity during the pause in the spatial working memory task, confirming that it harbors the circuits for that function. A region in the lower left frontal cortex (area 47 in the illustration) showed sustained activation during the pause in the face working memory task, thus clearly differentiating itself from the spatial working memory area.