Title: FEF-microstimulation causes task-dependent modulation of occipital fMRI activity
Authors: Premereur, Elsie
Janssen, Peter
Vanduffel, Wim # ×
Issue Date: Feb-2013
Publisher: Academic Press
Series Title: NeuroImage vol:67 pages:42-50
Abstract: Electrical microstimulation of FEF (FEF-EM) modulates neuronal activity in area V4 (Moore and Armstrong, 2003b) and elicits functional magnetic resonance imaging (fMRI) activations in visual cortex in a bottom-up dependent manner (Ekstrom et al., 2008n). Here we test the hypothesis that FEF-EM-induced modulations of fMRI activity are also function of task demands, which would suggest top-down dependent gating of FEF signals in early visual cortex. We scanned monkeys performing a passive fixation task with and without distractors, and a visually-guided saccade task with a very similar visual display. We found increased effects of FEF-EM on fMRI-activity in visual cortex during saccades compared to fixation, indicating that it is task-dependent, or enhanced in the presence of additional top-down signals. The EM-induced modulation of activity in FEF is correlated with that in LIP but not with that in visual cortex. On the other hand, FEF-EM-induced changes in early visual cortical activity are correlated with that in LIP, suggesting that LIP gates the information from FEF to visual cortex. Finally, the effect of FEF-EM is mainly present in voxels which were less activated by visual stimuli. Our results show that the FEF-EM-induced pattern of activation in early visual cortex is topographically specific and more pronounced during increased task demands.
ISSN: 1053-8119
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Research Group Neurophysiology
× corresponding author
# (joint) last author

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