MRI scan (resting MRI, DTI scan [diffusion tensor Imaging], GABA scan) MRI scan will be performed at CIRC, NUS by the staff of CIRC. Prior to the scan, all subjects will be briefed of the test procedure and safety aspects. All participants will be scanned on a 3-T GE scanner using a standard radiofrequency head coil. Head motion was minimized by foam padding and forehead-restraining straps.