Fos plumes. Coronal sections showing point sample positions used to identify local Fos plumes around microinjection site. A. Vehicle microinjection produces merely low elevation of Fos compared to normal virgin tissue. Radial arms extending from center show sampling points for Fos measurement (125 μm × 125 μm blocks; 5× magnification). B. CRF microinjection induces intense elevation over normal tissue levels (depicted by color: 10× elevation over normal denoted by yellow, 5× = dark orange; 2× = light orange). CRF also causes elevation compared to vehicle microinjection levels at equivalent points (depicted by dotted lines; 3× relative increase over vehicle-levels denoted by thick dotted line, 5× = thin dotted line; upper right; plume from CRF 500 ng dose in 0.2 μl microinjection volume).