Say goodbye to the most famous bunnies in the world.

Playboy Magazine announced yesterday (Oct. 12) that it was revamping its design. Among its changes: No longer will naked ladies grace the pages of the magazine. (Of course, you only read it for the articles anyway, right?)

"Playboy's great success was that it legitimized sexualized images in the context of good fiction, interesting articles and groundbreaking interviews," Kim Wallen, a psychologist at Emory University in Atlanta, Georgia, wrote in an email to Live Science. "Still, it would not have been able to sell these often-excellent features without including nude women, which was the reason a majority of men bought Playboy."

But ultimately, even the nude pictures weren't enough to hold readers. The magazine, which first exploded into public consciousness when it published nude shots of Marilyn Monroe in 1953, has been losing readers for years, according the Alliance for Audited Media., largely thanks to the rise of Internet pornography. With the click of a button, a smorgasbord of sexual options, from the violent and disturbing to the frankly weird, are instantly available. [Hot Stuff! 10 Unusual Sexual Fixations]

Yet porn has effects beyond siphoning readers from the lad mag of a bygone era. It may also be changing people in myriad subtle ways. Scientists don't fully understand how pornography affects people, but a few studies have revealed surprising — and disturbing — trends. From shrinking the brain to sabotaging relationships, here are five ways pornography affects the brain.

Same old, same old

Along with eating, drinking and sleeping, sex is one of the most fundamental human drives. That means it activates ancient parts of the brain such as the limbic system, which also controls basic emotions such as fear and anger, said Joseph J. Plaud, a private, clinical forensic psychologist in Boston, Massachusetts, who has studied the effects of pornography.

When people look at sexual imagery, dopamine floods these brain regions, causing an intense feeling of pleasure. Over time, people come to associate those direct images (called reinforcers) with the pleasurable feelings. Anything associated with those images, including Playboy's trademark bunny image, could also prime people to seek out that positive rush. [6 (Other) Great Things Sex Can Do for You]

However, if that pleasure response gets triggered over and over — with frequent doses of Playboy or other sexually charged imagery — a person will need bigger hits to feel a response, Plaud said.

"The more you do and the greater degree of access, the more explicit [it is], you seem to need more and more," Plaud told Live Science.

The incredible shrinking brain

Porn may also literally shrink the brain, a 2014 study in the journal JAMA Psychiatry found. Men who regularly consumed porn had smaller brain volume and fewer connections in the striatum, a brain region tied to reward processing, compared with those who didn't view porn.

However, it's possible this brain region shrinks simply because people become accustomed to viewing pornographic images, and thus find them less rewarding, one researcher previously told Live Science.

Additionally, the same brain regions are smaller in people who are depressed or suffer from alcoholism, and those people are less likely to be in relationships or have busy lives. So it may simply be that people who are depressed are more likely to view pornography, not that porn literally shrinks the brain, the researcher speculated.

Visual turnoff

Watching porn also seems to quiet a part of the brain that processes visual imagery, researchers reported in 2012 in the Journal of Sexual Medicine. It's not clear why this happens, but researchers speculated that the brain diverts blood flow from the visual cortex in order to focus on more pressing things, like being turned on.

The finding makes sense, in that people looking at pornography would be focusing on the sexually explicit image more than the fine details of the background of the image, the researchers speculated. A person who was scanning the horizon for potential threats would have trouble being aroused.

On the flip side, getting aroused requires feeling safe, and freedom from the need to look out for potential dangers, the researchers said.

Short-term mentality

Watching porn may also make people value immediate payoffs over delayed gratification, a study published in September in the Journal of Sex Research found.

Compared with people who abstained from eating their favorite food, people who were asked to abstain from porn for three weeks showed a lower rate of "delay discounting," meaning they were willing to wait longer for a reward. (Delay discounting refers to the phenomenon in which a reward becomes less valuable the longer one has to wait to receive it.)

So simply avoiding porn can put people into a more long-term mind-set, the researchers found.

Problem or not?

Is pornography use an unhealthy addiction that ruins men for relationships, or a healthy sexual outlet that both men and women enjoy? How people answer may affect whether they are harmed by porn. A study in the September issue of the journal Psychology of Addictive Behavior found that it was the perception of being "addicted to porn," rather than the intensity of porn use per se, that was tied with psychological distress.

And contrary to the notion that pornography fuels misogyny, men who viewed porn tended to hold more egalitarian views about women than did non-porn-using men. Frequent porn users view powerful women, working women and women who have had abortions more favorably than do other men, a study published in August in the Journal of Sex Research found.

That may be the case, but women in relationships with porn spectators reported being less happy in those relationships than gals paired up with men who didn't view pornography, found research published in 2012 in the journal Sex Roles.

Even though scientists are beginning to tease out the effects of porn on the brain, there's still a lot they don't understand, in particular about the long-term effect porn has on young viewers, Plaud said.

"We're being flooded by an immense amount of very hard-core pornography, and it's a question [what effect it has]," Plaud said. "I think it may have very large implications in the future."

Copyright 2015 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.