Connectivity by measures of conventional coherence and network topology. (A-C) Conventional coherence measures: (A) Mean coherence over all pairs of electrodes shows a significantly global under-connectivity for the Tuberous Sclerosis Complex (TSC) group regardless of the presence of Autism Spectrum Disorder (ASD). (B) Inter- versus intra-hemispheric coherence ratio. The significantly smaller value for patients with an absent corpus callosum (ACC) illustrates the validity of coherence as a connectivity measure. (C) Long- over short-range connectivity ratio is significantly smaller in the ASD group. As the mean coherence in (A) is not altered, this indicates a short-range overconnectivity and long-range underconnectivity in patients with ASD, evident in both subgroups (in ASD related to TSC and in ASD alone). (D-F) Network topology measures: TSC is characterized by a higher average path length (D) and lower clustering coefficient (E) and global efficiency (F). This departure from the small-world network topology results in a less functionally integrated and segregated network. No ASD group effect was found for these network topology measures. Only the lower alpha band is shown, see Table 1 for details. All measures are corrected for age. * P < 0.05, ** P < 0.01, *** P < 0.001.
Peters et al. BMC Medicine 2013 11:54 doi:10.1186/1741-7015-11-54