CONTROLLING ACCESS TO WORKING MEMORY
The term working
memory, proposed by Miller, Galanter and Pribram in 1960, in recent years
has been developed to emphasize the functional role of short term memory
(STM) as part of an integrated system for holding and manipulating information
during the performance of complex cognitive tasks. Storage capacity of our
working memory is limited, and it seems that part of the space is taken up by
irrelevant information. In a new research work, McNab and Klingberg show, using
functional magnetic resonance imaging (fMRI), that the basal ganglia
(specifically the globus pallidus) have an important role in filtering
out such irrelevant information to make working memory more efficient (McNab F. &
Klingberg T. Prefrontal cortex and basal ganglia control access to working
memory. Nature Neuroscience 11 (1), 103-107, 2008).
Trials revealed that the
“preparatory filtering activity” in the prefrontal cortex and globus
pallidus correlated positively with the voluntary’s working memory
capacity.
In brief, findings
indicate a role for the globus pallidus in filtering out information
that does not have to be stored in working memory and a contribution by
prefrontal cortex activity in flagging information that is necessary or worth
remembering.
Variation in activity and
connections in these areas might explain individual differences in working
memory capacity and help understanding some features of attention-deficit
disorders.