Enlargement and contrast of selected regions after 2-DE of mouse brain membranes (see areas defined in Fig 3). Areas i-vi show selective increases in spot number, resolution, and density. Samples were extracted with A) 4% CHAPS, B) 3% CHAPS : 1% LPC, C) 3% CHAPS : 1% MEGA 10, D) 3% CHAPS : 0.5% LPC : 0.5% MEGA 10. Results are representative of three independent experiments. Green arrows indicate spots showing increased volume and density, red arrows indicate decrease, blue arrows indicate novel spots.