Neuroimaging evidence for network sampling theory of human intelligence

Ethics approval
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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
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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
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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
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spm_deface was used on all anatomical images to ensure de-identification of subjects.