def data_scaling(Y):
    """Scaling of the data to have pourcent of baseline change columnwise

    Parameters
    ----------
    Y: array of shape(n_time_points, n_voxels)
       the input data
    
    Returns
    -------
    Y: array of shape(n_time_points, n_voxels),
       the data after mean-scaling, de-meaning and multiplication by 100
    mean: array of shape(n_voxels), the data mean
    """
    mean = Y.mean(0)
    Y = 100 * (Y / mean - 1)
    return Y, mean