Limitations of 2-dimensional line-scan MRI for directly measuring neural activity

• DOI: 10.1162/imag_a_00275
• Publication Date: 2024-08-12T20:02:01Z
• Authors: Joshua M. Wilson; Hua Wu; Adam B. Kerr; Brian A. Wandell; Justin L. Gardner
• Keywords: Mri scan; Neural Activity; Line (geometry)

Abstract A 2D-line-scan MRI sequence has been reported to directly measure neural responses stimuli (the “DIANA response”). Attempts replicate the DIANA response have failed, even with higher field strength and more repetitions. Part of this discrepancy is likely due a limited understanding how physiological noise manifests in acquisition sequences. Specifically, it unclear what consequences are breaking assumption that imaging substrate remains constant between each line acquisition. To answer question, we collected data at 3T from human subjects viewing blank screen. We found temporal fluctuations reconstructed time series could easily be confused stimuli. These were present both head surrounding empty volume along span phase-encoding direction head. The timing these varied systematically smoothly direction. artifacts similar well-known EPI GRE images, but exacerbated longer times (seconds vs. milliseconds). explain model accounts for incorporates time-varying contrast movement substrate. Using model, quantify amount cortical- scan-averaging one might need reliably distinguish noise, show navigator echoes help reducing phase-encode sequence.