Washington, Jul 1 (IANS): Scientists have established the mechanism that reveals how emotions are linked with the way humans hear and process sound, says a study.

When certain types of sounds become associated in our brains with strong emotions, hearing similar sounds can evoke those same feelings, even far removed from their original context.

It's a phenomenon commonly seen in combat veterans suffering from post-traumatic stress disorder (PTSD), in whom harrowing memories of the battlefield can be triggered by something as common as the sound of thunder.

But the brain mechanisms responsible for creating those troubling associations remain unknown, reports Science Daily.

Now, a pair of researchers from the Perelman School of Medicine at the University of Pennsylvania has discovered how fear can actually increase or decrease the ability to discriminate among sounds depending on context, providing new insight into the distorted perceptions of victims of PTSD.

"Emotions are closely linked to perception and very often our emotional response really helps us deal with reality," says senior study author Maria N. Geffen, assistant professor of Otorhinolaryngology: Head and Neck Surgery and Neuroscience at Penn.