  We analyze the high-resolution observations from the 1.6m telescope at Big
Bear Solar Observatory that cover an active region filament. Counter-streaming
motions are clearly observed in the filament. The northern end of the
counter-streaming motions extends to a light bridge, forming a spectacular
circulation pattern around a sunspot, with clockwise motion in the blue wing
and counterclockwise motion in the red wing as observed in Halpha off-bands.
The apparent speed of the flow is around 10 to 60 km/s in the filament,
decreasing to 5 to 20 km/s in the light bridge. The most intriguing results are
the magnetic structure and the counter-streaming motions in the light bridge.
Similar to those in the filament, magnetic fields show a dominant transverse
component in the light bridge. However, the filament is located between
opposite magnetic polarities, while the light bridge is between strong fields
of the same polarity. We analyze the power of oscillations with the image
sequences of constructed Dopplergrams, and find that the filament's
counter-streaming motion is due to physical mass motion along fibrils, while
the light bridge's counter-streaming motion is due to oscillation in the
direction along the line-of-sight. The oscillation power peaks around 4
minutes. However, the section of the light bridge next to the filament also
contains a component of the extension of the filament in combination with the
oscillation, indicating that some strands of the filament are extended to and
rooted in that part of the light bridge.
