specgram of EEG data

I'm working with data sampled at 500Hz but as you would know

    > we're more interested in the 0-50Hz range. Is the some way to
    > get the specgram() function to only show up a particular
    > frequency range rather than downsampling the data to a lower
    > sampling rate? I'm currently plotting with

    > specgram(data, Fs=500) colorbar() show()

Set the ylimits of the specgram axes to show only the frequency bad of

  specgram(data, Fs=500)
  ylim(0, 40)

    > but I'm not too sure where to go from here to achieve my
    > aims.

    > Thanks in advance and for putting together an amazingly
    > useful package.

Your welcome! You may want to check out my eegview package at
http://pbrain.sf.net. It's poorly documented and I don't have a lot
of time to support it currently, but there is already a lot there and
if you wanted to contribute some effort to that rather than starting
over, that would be great. We are in the process of trying to hire
someone to help with the development, maintenance and documentation of
that package, so I suspect it will see some activity in the not too
distant future.