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fMRI responses in medial frontal cortex that depend on the temporal frequency of visual input.
- Source :
-
Experimental Brain Research . Jun2007, Vol. 180 Issue 4, p677-691. 15p. 1 Chart, 9 Graphs. - Publication Year :
- 2007
-
Abstract
- Functional networks in the human brain have been investigated using electrophysiological methods (EEG/MEG, LFP, and MUA) and steady-state paradigms that apply periodic luminance or contrast modulation to drive cortical networks. We have used this approach with fMRI to characterize a cortical network driven by a checkerboard reversing at a fixed frequency. We found that the fMRI signals in voxels located in occipital cortex were increased by checkerboard reversal at frequencies ranging from 3 to 14 Hz. In contrast, the response of a cluster of voxels centered on basal medial frontal cortex depended strongly on the reversal frequency, consistently exhibiting a peak in the response for specific reversal frequencies between 3 and 5 Hz in each subject. The fMRI signals at the frontal voxels were positively correlated indicating a homogeneous cluster. Some of the occipital voxels were positively correlated to the frontal voxels apparently forming a large-scale functional network. Other occipital voxels were negatively correlated to the frontal voxels, suggesting a functionally distinct network. The results provide preliminary fMRI evidence that during visual stimulation, input frequency can be varied to engage different functional networks. [ABSTRACT FROM AUTHOR]
- Subjects :
- *ELECTROPHYSIOLOGY
*NEUROLOGY
*PHYSIOLOGY
*CEREBRAL cortex
*BRAIN
Subjects
Details
- Language :
- English
- ISSN :
- 00144819
- Volume :
- 180
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- Experimental Brain Research
- Publication Type :
- Academic Journal
- Accession number :
- 25511671
- Full Text :
- https://doi.org/10.1007/s00221-007-0886-3