Benny,

“Highlights & Shadows” will brighten the darkest shadows and darken the brightest highlights over the entire photo. “Dodge” and “Burn” are brushes that allow you to brighten (dodge) or darken (burn) over a very specific area. These terms come from the time of working in the darkroom and have to do with how the photographer would literally dodge the light out of areas hitting the print from the enlarger, or burn in spots longer than others.

-Joseph @ApertureExpert