In Vivo Brain Network Latency Connectome Mapping

National Institute Of Biomedical Imaging And Bioengineering, Bethesda

Investigators

Linked publications & trials

Abstract

We are pleased with the progress we have made in this "team building" R24 grant which our group received through the NIH BRAIN Initiative. This was the final year of our "no-cost extension" period. Until recently, ours had been the only group of NIH Intramural PIs to have received such an award. NIBIB, our intramural sponsor, has been extremely supportive of our efforts to build a "Dream Team" of computational neuroscientists, computer scientists with an expertise in networks, clinical neurophysiologists, magnetoencephalographers, MRI clinical pulse sequence programers, and bench neurobiologists. Although delayed by changes in administrative requirements within the NIH IRP, our group successfully received IRB approval of our proposed clinical protocol to enable us to perform interdisciplinary studies on healthy subjects, providing sufficient information to measure elements of the latency matrix in vivo for the first time. Prior to that, we performed several 'ground truth' studies intended to test and vet our proposed latency connectome methodologies, in one case, comparing latency measurements in the peripheral nervous system (PNS), using neurophysiological techniques on well characterized nerves in the motor system, along with MRI; and in the central nervous system (CNS), using TMS as a means to trigger controlled excitations between left and right motor areas, which we could compare with estimates furnished by MRI. We then focussed on vetting and validating the MRI method for measuring mean latencies and latency distributions. To date, we have performed numerous clinical studies in the PNS of subjects testing the accuracy and precision of the MRI latency estimates with those obtained neurophysiologically on the same subject. Two papers have now been published describing this novel method for measuring the latency between motor areas. A challenge for this research project continues to be that there is no "gold standard" or ground truth measurement of a "latency connectome" or latency graph with with to compare and contrast our findings.