  The dynamics of a filament channel are observed with imaging and
spectroscopic telescopes before and during the filament eruption on 2011
January 29. The extreme ultraviolet (EUV) spectral observations reveal that
there is no EUV counterparts of the H$\alpha$ counter-streamings in the
filament channel, implying that the ubiquitous H$\alpha$ counter-streamings
found by previous research are mainly due to longitudinal oscillations of
filament threads, which are not in phase between each other. However, there
exist larger-scale patchy counter-streamings in EUV along the filament channel
from one polarity to the other, implying that there is another component of
uni-directional flow (in the range of $\pm$10 km s$^{-1}$) inside each filament
thread in addition to the implied longitudinal oscillation. Our results suggest
that the flow direction of the larger-scale patchy counter-streaming plasma in
the EUV is related to the intensity of the plage or active network, with the
upflows being located at brighter areas of the plage and downflows at the
weaker areas. Besides, we propose a new method to determine the chirality of an
erupting filament based on the skewness of the conjugate filament drainage
sites. It suggests that the right-skewed drainage corresponds to sinistral
chirality, whereas the left-skewed drainage corresponds to dextral chirality.
