Timing Issue with HCP fMRI Physiological Monitoring Data To investigators who have been using or are considering using the physiological monitoring data released for the HCP Q1 - Q3 datasets: The HCP has discovered that the timing of physiological monitoring data released during Q1 - Q3 is offset due to a roughly 500 ms delay in the onset of recording for the respiratory, pulse oximetry, and external trigger signal during fMRI runs. Because the onsets of the log files for each of these physiological modalities were not simultaneous as we expected them to be, the physiological data in the processed log files (e.g., tfMRI_WM_RL_Physio_log.txt) was also offset. More specifically, relative to the external trigger signal contained in the processed log files, the respiratory signal was delayed by roughly 1000 ms and the pulse-oximeter signal was delayed by roughly 1500 ms.
We are taking steps to remedy this issue and correctly re-align the onsets of the physiological signals with the external trigger signal in the processed log files. This will be done retroactively for all Q1-Q3 data, as well as applied to all new participants to be released in the future. The relevant patch for previously-released physio data will be released as soon as is feasible, but we do not yet have a projected release date for this patch. We apologize to any investigators whose research is impacted by this problem. The HCP Team ____________________________________________________________________ Greg Burgess, Ph.D. Staff Scientist, Human Connectome Project Washington University School of Medicine Department of Anatomy and Neurobiology Email: burge...@pcg.wustl.edu _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org http://lists.humanconnectome.org/mailman/listinfo/hcp-users
