Editing Afterimage (section)

==Positive afterimages==
Positive afterimages, by contrast, appear the same color as the original image. They are often very brief, lasting less than half a second. The cause of positive afterimages is not well known, but possibly reflects persisting activity in the [[visual cortex|brain]] when the [[retina]]l [[photoreceptor cell]]s continue to send neural impulses to the [[occipital lobe]].<ref>{{Cite web|url=http://www.exo.net/~pauld/activities/perception/positiveafterimage.html|title=positiveafterimage|website=www.exo.net}}</ref>

A stimulus which elicits a positive image will usually trigger a negative afterimage quickly via the adaptation process. To experience this phenomenon, one can look at a bright source of light and then look away to a dark area, such as by closing the eyes. At first one should see a fading positive afterimage, likely followed by a negative afterimage that may last for much longer. It is also possible to see afterimages of random objects that are not bright, only these last for a split second and go unnoticed by most people. {{citation needed|date=March 2015}}