Vivid visions of intense imagery

Emotionally charged events are generally remembered and perceived more vividly in our brains. While this emotional boost doesn’t do much for accuracy when recalling the event, it does crank our ability to detect and see subject matter that gets people’s norepinephrine flowing, especially if those people lack the adrenoreceptors to stop the process.

To test vividness of perception, test subjects were shown images with equal amounts of visual noise added to partially obscure the subject matter. When an image was of something that is commonly emotionally arousing, such as snakes ready to strike, spiders or dessert, people would report that that image had less noise than emotionally neutral subjects. What was actually happening was that their brain was amplifying the contrast and color, making the subject easier to identify (which, in the example of the rearing snake, has been linked to why primates have advanced color perception in the first place.)

This memory goes to 11

People with a variation on the ADRA2b gene experienced this effect even more strongly. In all subjects stress triggers the output of norepinephrine, but those with the mutation lack some of their alpha2b adrenorecptors in their locus coeruleus, which would act to slow or stop the effects of the norepinephrine. These subject then don’t experience the usual drop-off in their stress response, which in this context means their visual perception of emotional images is even more vivid than normal.

Source: A vivid emotional experience requires the right genetics by Bethany Brookshire, Scicurious