February 17, 2014
Science Daily/INSERM (Institut national de la santé et de la recherche médicale)
The reason for dreaming is still a mystery for the researchers who study the difference between "high dream recallers," who recall dreams regularly, and "low dream recallers," who recall dreams rarely. 

http://images.sciencedaily.com/2014/02/140217085915-large.jpg

In January 2013 (work published in the journal Cerebral Cortex), the team led by Perrine Ruby, Inserm researcher at the Lyon Neuroscience Research Center, made the following two observations: "high dream recallers" have twice as many time of wakefulness during sleep as "low dream recallers" and their brains are more reactive to auditory stimuli during sleep and wakefulness. This increased brain reactivity may promote awakenings during the night, and may thus facilitate memorization of dreams during brief periods of wakefulness.

High dream recallers, both while awake and while asleep, showed stronger spontaneous brain activity in the medial prefrontal cortex (mPFC) and in the temporo-parietal junction (TPJ), an area of the brain involved in attention orienting toward external stimuli.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/02/140217085915.htm