Fig 1.
Sequence of imaging and testing periods, including one hour of control or 60 Hz MF exposure to a 60 Hz MF at 3000 μT during one hour.
Fig 2.
The maximal MF level was obtained at the cortical level. The variation of the MF intensity depends on the position along the bore Z-axis and is shown in red. The MF intensity delivered by the gradient coil linearly decreases to reach zero at the isocentre (at the level of the first cervical vertebrae).
Fig 3.
Functional brain activation—primary somatosensory cortex (S1).
S1: Top row—Tapping: pre-exposure group image (N = 9). Middle row—Tapping: post- minus pre-exposure condition (control, N = 5). Bottom row—Tapping: post- minus pre-exposure condition (60 Hz MF, N = 4). Results centered on the point of Talairach coordinates (X = -40, Y = -31, Z = 52).
Fig 4.
Functional brain activation—anterior cingulate cortex.
AC: Top row—Tapping: pre-exposure group image (N = 9). Middle row—Tapping: post- minus pre-exposure condition (control, N = 5). Bottom row—Tapping: post- minus pre-exposure condition (60 Hz MF, N = 4). Results centered on the point of Talairach coordinates (X = -7, Y = -6, Z = 39).
Fig 5.
Functional brain activation—cerebellum.
Cerebellum: Top row—Tapping: pre- exposure group image (N = 9). Middle row—Tapping: post- minus pre-exposure condition (control, N = 5). Bottom row—Tapping: post- minus pre-exposure condition (60 Hz MF, N = 4).
Fig 6.
Pre-exposure finger tapping averaged activation map of the contralateral motor cortex regions (top row) and the ipsilateral cerebellum (bottom row) for 20 participants for the full study at 3000 μT.
The contralateral motor cortex images (top row) presented are centered on the Talairach coordinates corresponding to S1 (x = -41, y = -31, z = 53) for the motor cortex region. The ipsilateral cerebellum images (bottom row) presented are centered on the Talairach coordinates corresponding to the anterior lobe of the ipsilateral cerebellum (x = 18, 7 = -47, z = -15).
Fig 7.
Increased activation in S1 in the 60 Hz MF exposure group.
*(All images were normalized in Talairach space—BrainVoyager GLM analysis). Results centered on the point of Talairach coordinates (X = -40, Y = -31, Z = 52). Fig 7. Top) Pre-exposure activation and deactivation for all subjects (N = 20). Fig 7. Middle) Post—minus- pre control exposure (N = 11). Fig 7. Bottom) Post- minus- pre 60 Hz MF exposure (N = 9).
Fig 8.
Increased activation in the anterior lobe of the ipsilateral cerebellum in the 60 Hz MF exposure group (All images were normalized in Talairach space—BrainVoyager GLM analysis).
Results centered on the point of Talairach coordinates (X = 18, Y = -47, Z = -15). Fig 8. Top) Pre-exposure activation and deactivation for all subjects (N = 20). Fig 8. Middle) Post-minus-pre control exposure (N = 11). Fig 8. Bottom) Post-minus-pre 60 Hz MF exposure (N = 9).
Fig 9.
Activation in the posterior cingulate during the mental rotation task.
Top) Pre-exposure (N = 21); Middle) Post- minus pre- exposure in the control group (N = 11); Bottom) Post- minus pre- exposure in the 60 Hz MF exposure group (N = 10). Results centered on the point of Talairach coordinates (X = -5, Y = -53, Z = 16).
Fig 10.
Activation in the left intraparietal sulcus during the mental rotation task.
Top) Pre-exposure (N = 21); Middle) Post- minus pre- exposure in the control group (N = 11); Bottom) Post- minus pre- exposure in the 60 Hz MF exposure group (N = 10). Results centered on the point of Talairach coordinates (X = -30, Y = -84, Z = 18).
Fig 11.
Activation in the right occipital cortex during the mental rotation task.
Top) Pre-exposure (N = 21); Middle) Post- minus pre- exposure in the control group (N = 11); Bottom) Post- minus pre- exposure in the 60 Hz MF exposure group (N = 10). Results centered on the point of Talairach coordinates (X = 27, Y = -59, Z = -23).
Fig 12.
Time series of the magnetic induction measured during the 60 Hz and BOLD sequences.
Fig 13.
Comparison of the magnetic induction power spectrum for the 60 Hz and BOLD sequences.