We propose to use the ISOCAM instrument to obtain mid-infrared
  spectral imaging data for the bulges of 4 early-type spiral galaxies
  with LINER nuclei.  These data will be complementary to our high spatial
  resolution 50 and 100 micron observations of these bulges, obtained
  with the Kuiper Airborne Observatory.  Our KAO observations show that
  these bulges are quite luminous in the far-infrared, and the
  far-infrared emitting regions are quite extended (FWHM = 1 kpc = 30").
     Our goals in the proposed mid-infrared studies are:
  1) to determine the mid-infrared continuum distribution across
  these bulges (is it similar to that in the far-infrared?  Can we
  identify morphological features, such as bars and circumnuclear rings,
  which are unresolved in the far-infrared?).
  2) to determine the infrared spectral energy distribution as a function
  of position in these bulges (are there strong mid-infrared color
  temperature gradients across the bulges?  are emission lines present?
  Are silicate absorption lines seen?).
  3) to determine the distribution of very small dust grains in
  these bulges, via the `unidentified' mid-infrared emission lines
  (are the emission features non-existent near the LINER nucleus,
  and bright elsewhere in the bulge? or the reverse? is the distribution
  of small grains similar to that of the far-infrared continuum?).
  4) to compare the mid-infrared properties of these relatively quiescent
  bulges to those containing starbursts and Seyfert nuclei.