  We have used the Gemini Near-infrared Integral Field Spectrograph (NIFS) to
map the emission-line intensity distributions and ratios in the Narrow-Line
Region (NLR) of the Seyfert galaxy NGC 4151 in the Z, J, H and K bands at a
resolving power ~ 5000, covering the inner 200 pc x 300 pc of the galaxy at a
spatial resolution of 8 pc. We present intensity distributions I(r) in 14
emission lines. (1) For the ionized gas, I(r) is extended to ~ 100 pc from the
nucleus along pos. angle PA=60/240 deg-- NE--SW), consistent with an origin in
the known biconical outflow; while for the recombination lines I(r) ~ r^-1, for
the forbidden lines I(r) is flat (r^0). (2) The H_2 emission lines intensity
distributions avoid the region of the bicone, extending to r ~ 60 pc,
perpendicular to the bicone axis, supporting an origin for the H_2-emitting gas
in the galaxy plane. (3) The coronal lines show a steep intensity profile,
described by r^-2. Using the line-ratio maps [Fe II]1.644/1.257 and Pa_b/Br_g
we obtain a reddening of E(B-V)~0.5 along the NLR and E(B-V)>1 at the nucleus.
Our line-ratio map [Fe II] 1.257/[P II] 1.189 is the first such map of an
extragalactic source. Together with the [Fe II]/Pa_b map, these line ratios
correlate with the radio intensity distribution, mapping the effects of shocks
produced by the radio jet, which probably release the Fe locked in grains and
produce the enhancement of the [Fe II] emission observed at ~ 1 arcsec from the
nucleus. At these regions, we obtain densities N_e ~4000 cm^-3 and temperatures
T_e ~ 15000K for the [Fe II]-emitting gas. For the H_2-emitting gas we obtain T
~ 2100K. The distinct intensity distributions, physical properties and
locations of the ionized and molecular gas suggest that the H_2-emitting gas
traces the AGN feeding, while the ionized gas traces its feedback.
