Chen, C.-f. and Kreutz-Delgado, K. and Sereno, Martin I. and Huang, R.-S. (2017) Validation of periodic fMRI signals in response to wearable tactile stimulation. NeuroImage 150 , pp. 99-111. ISSN 1053-8119.
Abstract
To map cortical representations of the body, we recently developed a wearable technology for automatic tactile stimulation in human functional magnetic resonance imaging (fMRI) experiments. In a two-condition block design experiment, air puffs were delivered to the face and hands periodically. Surface-based regions of interest (S-ROIs) were initially identified by thresholding a linear statistical measure of signal-to-noise ratio of periodic response. Across subjects, S-ROIs were found in the frontal, primary sensorimotor, posterior parietal, insular, temporal, cingulate, and occipital cortices. To validate and differentiate these S-ROIs, we develop a measure of temporal stability of response based on the assumption that a periodic stimulation evokes stable (low-variance) periodic fMRI signals throughout the entire scan. Toward this end, we apply time-frequency analysis to fMRI time series and use circular statistics to characterize the distribution of phase angles for data selection. We then assess the temporal variability of a periodic signal by measuring the path length of its trajectory in the complex plane. Both within and outside the primary sensorimotor cortex, S-ROIs with high temporal variability and deviant phase angles are rejected. A surface-based probabilistic group-average map is constructed for spatial screening of S-ROIs with low to moderate temporal variability in non-sensorimotor regions. Areas commonly activated across subjects are also summarized in the group-average map. In summary, this study demonstrates that analyzing temporal characteristics of the entire fMRI time series is essential for second-level selection and interpretation of S-ROIs initially defined by an overall linear statistical measure.
Metadata
| Item Type: | Article |
|---|---|
| Keyword(s) / Subject(s): | Wearable tactile stimulation, Human somatotopy, Linear systems analysis, Time-frequency analysis, Signal stability |
| School: | Birkbeck Faculties and Schools > Faculty of Science > School of Psychological Sciences |
| Research Centres and Institutes: | Neuroimaging, Birkbeck-UCL Centre for (BUCNI) |
| Depositing User: | Administrator |
| Date Deposited: | 07 Mar 2017 13:50 |
| Last Modified: | 02 Aug 2023 17:31 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/18291 |
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