FIG 1. Theophylline effect on the BOLD fMRI response to left forepaw electrical stimulation. Data are shown for a single section through the sensory cortex in a single animal at baseline (left) and 60 minutes after the administration of 0.1 mmol/kg systemic theophylline (right).

A, The number of activated voxels significantly increased 60 minutes after the administration of systemic theophylline. Arrows indicate the most significantly activated voxel, which had the same location on both images.

B, BOLD response for the voxel indicated in A. Bars to the right of each graph indicate the average signal intensity during forepaw stimulation (upper bars) and at rest (lower bars). The double-arrowhead vertical lines to the right of each graph indicate the BOLD response amplitude. The BOLD response amplitude significantly increased 60 minutes after systemic theophylline compared with the baseline. Horizontal bars above each graph indicate periods of forepaw electrical stimulation with a 4-second hemodynamic delay.