SEQUENTIAL HEMODYNAMIC ACTIVATION OF MOTOR AREAS AND THE DRAINING VEINS DURING FINGER MOVEMENTS REVEALED BY CROSS-CORRELATION BETWEEN SIGNALS FROM FMRI

ACTIVITY in the human supplementary motor area (SMA), primary motor co rtex (M1), and the draining vein of the motor cortex during a visually triggered finger opposition task was measured by functional magnetic resonance imaging with a repetition time of Is. Sequential hemodynamic activation in these areas was revealed by cross-correlating a signal sequence in M1 directly with signal sequences from SMA and the drainin g vein, and applying polynomial fitting with the aid of Akaike's infor mation criterion. We succeeded in detecting a time delay of approximat ely 0.5 s between the activations of SMA and M1, and a delay of nearly 1.3 s between the activations of M1 and its draining vein. The new co mbination of fMRI and data analysis techniques has attained a time res olution comparable to those in preceding studies that used shorter fMR I repetition times of 100-200 ms. (C) 1998 Rapid Science Ltd.