Open AccessNeural correlates of the interaction between transient and sustained processes: A mixed blocked/event‐related fMRI study
Author(s) -
Scheibe Christina,
Wartenburger Isabell,
Wüstenberg Torsten,
Kathmann Norbert,
Villringer Arno,
Heekeren Hauke R.
Publication year - 2006
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.20199
Subject(s) - precuneus , neuroscience , categorization , cognition , psychology , neuroimaging , transient (computer programming) , task (project management) , cognitive psychology , brain activity and meditation , event related potential , computer science , artificial intelligence , electroencephalography , management , economics , operating system
Complete understanding of the neural correlates of cognitive processes requires investigation of both event‐ and state‐related correlates of cognitive performance as well as their interaction. Neuroimaging studies using blocked designs confound these two types of processes and studies using event‐related designs focus exclusively on the detection of transient effects. Recent fMRI studies used mixed blocked/event‐related designs and found that transient and sustained activity can be dissociated, but it is not yet known how event‐related and state‐related processing interact. Here we used a phonological categorization paradigm in a mixed blocked/event‐related design to investigate where in the brain transient activity interacts with sustained activity. Task difficulty was parametrically manipulated based on individually determined categorization thresholds. We found an interaction effect of transient and sustained activity in the left precuneus. In this cortical structure transient activity increased with increasing task difficulty, while sustained neural activity decreased with increasing task difficulty. Our data suggest that sustained activity is enhanced during processing of an easy task, presumably because of ongoing internally cued endogenous processing, still allowing effortless processing of transient stimuli. During performance of a difficult task, sustained activity in the precuneus is reduced to provide resources for processing incoming stimuli. Processing of stimuli that are expected to be difficult elicits increased transient responses independent of the actual physical properties of the stimuli. In showing an interaction between transient and sustained activity in the precuneus, the present results accommodate seemingly diverging results from previous studies using event‐related or blocked designs and expand the knowledge emerging from previous studies using mixed blocked/event‐related designs. Hum Brain Mapp, 2005. © 2005 Wiley‐Liss, Inc.