A structural T1 is typically acquired immediately before/after the functional fMRI data acquisition. In addition, the T1 image is often acquired in the same scanner and space of the fMRI data, which facilitate their intermodal coregistration. In this study, we took advantage of FreeSurfer’s parcellation and segmentation (Fischl et al. 2002, 2004) Inhibitors,research,lifescience,medical to accurately locate ROI in the subject’s native space. Then we transferred the FreeSurfer regional mask to fMRI space and obtained a single averaged

resting-state BOLD signal in every region. This method enables us to compare regional connectivity in young and elder brains without requiring the problematic TGF-beta inhibitor preprocessing steps of spatial normalization and smoothing. It also provides higher statistical power because location-specific signals are more accurately captured. A similar method for analysis of Inhibitors,research,lifescience,medical resting-state BOLD fMRI data in surface space has been reported previously (Seibert and Brewer 2011). In that study, FreeSurfer was used to identify ROIs in native surface space on the cortex, whereas in the proposed method here we used the volumetric

mask of each ROI (both for cortical Inhibitors,research,lifescience,medical and subcortical regions) to extract the regional signal. We used the additional power afforded by this method to examine age-related changes in DMN connectivity in each hemisphere separately rather than the prevailing approach of averaging ROIs across hemispheres. Furthermore, we investigated whether this disruption is truly Inhibitors,research,lifescience,medical bilateral in nature or has unilateral characteristics. To investigate the effects of interhemispheric averaging, we repeated the native space analysis by averaging both hemispheres’ regional time series in the analysis of resting-state BOLD fMRI Inhibitors,research,lifescience,medical data. We compared the results of the proposed native space method to those obtained using the commonly adopted approach of spatial normalization and smoothing. Finally, in the DMN regions that are found to be significantly different between age groups, we examined the relationship between the strength of their functional connectivity and cognitive performance. Method Subjects Twenty-five young healthy participants

(11 M, 14 F, mean age: 25.36 years, SD age: 2.74 years), and 26-year-old healthy participants (12 M, 14 F, mean age: 65.11 years, SD age: 2.98 years) were recruited through random market mailing from within 10 miles of the Columbia University Medical Center. isothipendyl This recruitment approach is intended to obviate cohort effects that might be present by using convenience samples. All 51 subjects were right handed and did not differ regarding their level of education (young: 15.5 ± 2.06 years old: 15.27± 3.04 years). As can be seen, an extensive effort was made to make the two age groups comparable in their education, method of recruitment, geographical area of residence, male-to-female ratio, and within-group age distribution.