Author Affiliations: Department of Neurology, Memory and Aging Center, University of California, San Francisco, California.
Noninvasive methods for large-scale network analysis have begun to transform human neuroscience. These “connectomic” mapping approaches bring the potential to measure structural and functional network integrity at high resolution in single subjects. Applied to healthy individuals, these techniques have begun to outline a pantheon of robust and reproducible networks,1 clarify connectivity-behavior relationships,2 and explore dynamic network-network interactions.3 Connectomics have become equally attractive to clinical neuroscientists as a means to investigate symptom pathogenesis, disease mechanisms, and candidate diagnostic or disease-monitoring biomarkers. The article in this issue of the Archives by Machulda et al4 applies a functional connectomic method, “task-free” or intrinsic connectivity network (ICN) functional magnetic resonance imaging, to healthy elders with or without an apolipoprotein E ε4 (APOE ε4) allele. The findings fuel hope that ICN mapping may detect and follow up preclinical disease, but they also highlight evolving questions with regard to network disruption and enhancement in patients with early and selective neurodegeneration.
Seeley WW. Divergent Network Connectivity Changes in Healthy APOE ε4 CarriersDisinhibition or Compensation?. Arch Neurol. 2011;68(9):1107-1108. doi:10.1001/archneurol.2011.202