[Dion]

Internet porn is especially enticing to the reward circuitry because novelty is always just a click away. It could be a novel “mate,” unusual scene, strange sexual act, or—you fill in the blank. With multiple tabs open and clicking for hours, you can experience more novel sex partners every ten minutes than our hunter-gatherer ancestors experienced in a lifetime.

What’s a brain to do when it has unlimited access to a super-stimulating reward it never evolved to handle? Some brains eventually adapt, which can lead to addiction-related brain changes. Research confirms anticipation of reward and novelty amplify one another to increase excitement and rewire the limbic brain.

I can't emphasize this enough: Internet porn addiction is not a "sex addiction" - it's an Internet addiction. Although masturbation is often involved, this is an addiction to novel pixels on a screen.

As sensitization and cravings compel you to use porn, overstimulation of the reward circuitry leads to a localized rebellion. The nerve cells bombarded by dopamine say "enough is enough." If someone continues to scream, you cover your ears. When dopamine-sending nerve cells keep pumping out dopamine, the receiving nerve cells cover their "ears" by reducing dopamine (D2) receptors.

As desensitization numbs you to everyday pleasures, sensitization makes your brain hyper-reactive to anything associated with your porn addiction. Over time, this dual-edged mechanism can have your reward circuitry buzzing at the hint of porn use, but less than enthused when presented with the real deal. Desensitization is not "damage." If your cells wanted, they could rebuild lost dopamine receptors in a few minutes. Rather, desensitization represents a negative feedback system in overdrive.

http://yourbrainonporn.com/doing-what-you-evolved-to-do