Recordings of Pi 1 and Pi 2 pulsations obtained on a short-distance network of magnetometer stations were used to investigate the relationship between fluctuations of the auroral zone currents and geomagnetic pulsations. During the early part of the substorm expansion phase the pulsations of the D and H components are decoupled from each other at all stations. Similarily, the pulsations of the D components are not significantly correlated at stations with separation distances of approximately 100 km. For this interval the pulsations of the H component are interpreted as being predominantly the magnetic effect of fluctuations of the auroral electrojet, and the pulsations of the D component as being a consequence of fluctuations of Birkeland sheet currents. The conclusion can be drawn from these observations that the Birkeland currents are not directly connected in the north-south direction. Thus a considerable east-west component of the currents is required in order to maintain current continuity in the ionosphere. These effects disappear in the late expansion phase and early recovery phase.