Neuroimaging evidence for network sampling theory of human intelligence

Ethics approval ------------------------------------- This study was approved by the University of Western Ontario ethics committee. All participants provided written consent before taking part in the study. Subjects and MRI protocol ------------------------------------- Sixty adults (35 females, mean age 22.95, range 18-38 years of age), all with normal hearing and corrected to normal vision were included in the study. Participants were recruited from the University of Western Ontario and surrounding area. Whole-brain images were collected using a 3 Tesla scanner (TIM Trio, Siemens, Erlangen, Germany). FMRI data were collected across twelve runs (60 min total). During functional scans, a T2-weighted echo-planar image depicting blood oxygenation level-dependent (BOLD) contrast was acquired every 2s. The first ten images were discarded to account for equilibrium effects. Images consisted of 36*3 mm slices, with an 80 x 80 matrix, 240 x 240 mm field of view, TE=30ms, flip angle=90\degree, echo spacing=2.65ms. A 1 mm resolution MPRAGE structural scan was also collected for each participant with a 256 x 240 x 384 matrix, TI=900ms, TR=2.3s, TE=2.98ms and 9\degree flip angle. Task protocol ------------------------------------ All participants engaged with twelve cognitive tasks designed to measure planning, reasoning, attention, and working memory abilities that are believed to be core intelligence abilities. Before scanning, participants underwent a short training session to ensure that they could perform all 12 tasks. The training consisted of reading written instructions followed by one practice block of each task, undertaken on a laptop outside of the MRI scanner. Each participant then undertook twelve functional runs, one for each specific task. These were administered in a predefined order. Each experimental run contained three blocks each one-minute long, separated by 20s of rest. Tasks were displayed on a projector screen, visible from the bore of the MRI scanner via a mirror. Responses were taken with a custom MRI compatible mouse. In the imaging study, the tests ran as stand-alone software within the Adobe AIR run-time environment. Defacing ------------------------------------ spm_deface was used on all anatomical images to ensure de-identification of subjects.