Behavioral and Brain Sciences

Short Communication

Functional neuroimaging of short-term memory: The neural mechanisms of mental storage

Bart Rypma a1 and John D.E. Gabrieli a2
a1 University of California, Department of Psychology, Berkeley, CA 94720-1650
a2 Department of Psychology, Stanford University, Stanford, CA 19001


Cowan argues that the true short-term memory (STM) capacity limit is about 4 items. Functional neuroimaging data converge with this conclusion, indicating distinct neural activity patterns depending on whether or not memory task-demands exceed this limit. STM for verbal information within that capacity invokes focal prefrontal cortical activation that increases with memory load. STM for verbal information exceeding that capacity invokes widespread prefrontal activation in regions associated with executive and attentional processes that may mediate chunking processes to accommodate STM capacity limits.