18.5.11

Love, Sex, and Pleasure ...explained in a neuro chemical way!




Ever wonder why sex feels so good?  Why we fall in love?  What makes you feel attracted to the other person?  Why does love fade after a while?  What happens when you have an orgasm?  Its all chemical my friends....


 Thips article does a GREAT job of explaining all of these processes from a biological and psychological point of view.  I guess its the former psych major and bio geek coming out in me......have a read...its a bit heavy on the technical terms but it really does do a great job of explaining how we are hard wired from an evolutionary point of view. 







Let’s look at what goes on in the brain during sex and orgasm. Although you may think everything happens between your legs, the experience of orgasm actually occurs between your ears. All thoughts, feelings, and bodily sensations you have correlate to specific nerve cells being activated. Orgasm, like all experiences, is brought about by electric impulses flowing along paths of connected nerve cells. Orgasm happens when specific pleasure pathways are turned on, while your defense pathways are turned off. All this happens by means of chemical messengers and the nerve cell receptors they bind to.
These neurochemical changes take place primarily in the limbic system, a very old part of the brain with circuitry that is common to all mammals. These ancient limbic circuits control almost all bodily functions. Its job is to keep you alive and reproducing. It does this by avoiding pain and repeating what is pleasurable. The limbic system is the seat of emotions, drives, impulses and desires – including sexual. It’s where you fall in and out of love…or lust. Due to the nature of the limbic system, you cannot will your feelings, emotions, falling in love, or staying in love, anymore than you can will your heart to beat, or yourself to digest a meal or sleep.
The limbic system has been around for well over 100,000,000 years, lurking right beneath your large, rational neo-cortex. Rats, apes and humans use the same neurochemicals to operate the same functions in this part of the brain. Keep in mind that scientists aren't studying rodent brains to help them with their addictions and erections!
Studying animals and humans, scientists have begun to unravel the neurochemistry of lust, attachment and falling in love. Falling in love involves simultaneous activation and deactivation of discrete parts of the limbic system. For every biological event in your body, there is a biological cause. In this case, the cause is neurochemicals—and the pathways they turn on and off.

Neurochemical Commands: Your World Revolves Around Dopamine

brain's reward circuitryThe central neurochemical player behind falling in—and out—of love is dopamine. Dopamine is the principal neurochemical that activates your reward circuitry, the centerpiece of the limbic system. Your reward circuitry drives nearly all of your behaviors. In other words, most all roads lead to Rome, or to the reward circuitry, so you can assess things as "good, bad, or indifferent."
At its most basic, this circuit is activated when you engage in activities that further your survival, or the continuation of your genes. Whether it’s sex, eating, taking risks, achieving goals, or drinking water, all increase dopamine, and dopamine turns on your reward circuitry. You can think of dopamine as the "Gotta have it!" neurochemical, whatever "it" is. It’s the "craving" signal.
The more dopamine you release and the more your reward circuit is activated, the more you want or crave something. A good example is food. We get a much bigger blast of dopamine eating high-calorie foods than we do low-calorie foods. It’s why we choose chocolate cake over Brussels sprouts. Our reward circuit is programmed so that "calories equal survival." cake slice You’re not actually craving ice cream, or a winning lotto ticket, or even a romp in the sack. You’re craving the dopamine that is released with these activities. Dopamine is your major motivation, not the item or activity.
Dopamine is not the only neurochemical involved with reward, but it’s the one that motivates you to go after the reward. Dopamine governs the feelings of wanting, yet the experience of liking or enjoying something is probably due to opioids. Opioids are your brains own morphine and endorphins. Dopamine drives us toward eating or orgasm, but the experience of the actual orgasm or eating chocolate arises from opioids goosing the reward circuit. In essence, dopamine is never satisfied.
Addiction mechanisms are extraordinarily complex, and not fully understood. Yet the one aspect they share is dopamine dysregulation. All addictive substances and activities share one thing – the ability to strongly elevate dopamine levels. Watching porn, accumulating money, gaining power over others, gambling, compulsive shopping, video games…if something really boosts your dopamine, then it’s potentially addictive for you. Why did Martha Stewart risk everything for more money? She got a thrill from a stock market gamble. She didn’t need the money; she (thought she) needed the dopamine.
Addictive highs mimic the good feelings of the basic activities for which we're actually wired...by hijacking our reward circuitry. Only a few substances (alcohol, cocaine, etc.) have the ability jack up dopamine – that’s why they are addictive. We can also hijack it with extremely stimulating versions of natural behaviors: casinos with hot hostesses, novel porn at every click, tasty junk food filled with fat and sugar, and so forth.
Dopamine loves novelty and the unexpected above all other natural stimuli.
Don't fall into labeling dopamine as bad. There's no such thing as a bad neurochemical or hormone, although either can become a problem when out of balance. Dopamine is absolutely necessary for your decision-making, happiness, and survival. Yet when it’s too low or too high (or when changes in its receptors alter your sensitivity), it can cause real problems.
If you look at this chart you can see some behaviors and conditions associated with dopamine levels or with sensitivity to dopamine. Sensitivity equates with how many receptors a nerve cell has for dopamine. It's true that some of the conditions listed are at extreme ends of the dopamine spectrum, nonetheless, dopamine is involved with many aspects of mood, behavior, and perception. Even small shifts in dopamine sensitivity or levels can have profound effects on how you see the world, or your partner.
The key word on the list below is bonding. Bonding is more than a behavior. It is a mammalian program, the program that permits parenting and living in groups. When dopamine drops, you are likely to find your partner less rewarding—and your bond unravels.

Dopamine Levels (or altered sensitivity to dopamine)

Excess Deficient "Normal"
Addictions Addictions Healthy bonding
Anxiety Depression Feelings of well-being, satisfaction
Compulsions Anhedonia—no pleasure, world looks colorless Pleasure, reward in accomplishing tasks
Sexual fetishes Lack of ambition and drive Healthy libido
Sexual addiction Inability to "love" Good feelings toward others
Unhealthy risk-taking Low libido Motivated
Gambling Erectile dysfunction Healthy risk taking
Compulsive activities No remorse about personal behavior Sound choices
Aggression ADHD or ADD Realistic expectations
Psychosis Social anxiety disorder Parent/child bonding
Schizophrenia Sleep disturbances, "restless legs" Contentment with "little" things
The power of dopamine and our reward circuitry is seen in classic experiments done of rats. Researchers placed electrodes in rats’ reward circuits in a way that allowed the rats to stimulate them, much as dopamine does. The rats then stimulates this reward center as much as they wanted by pressing a lever.
That’s all those rats did thousands of times an hour. rat pushing leverThey ignored food, receptive females and their own pups, if female. They just sat there pressing the lever over and over, wasting away…not unlike crack addicts.
(For more on how this "binge trigger" works, see this more recent article: Has Evolution Trained Our Brains to Gorge on Food and Sex? )
In other experiments, scientists blocked dopamine so the reward center could not be activated by normal everday stimuli. What happened? The rats just sat there, again—ignoring food, receptive mates, and the opportunity to explore their environment.

Dopamine and Orgasm

Orgasm is the biggest non-chemical blast of dopamine available to us. A Dutch scientist scanned the brains of people having orgasm. He said they resembled scans of heroin rushes. He saw visions of an "orgasm pill" and lots of money. We saw visions of one of the most addictive substance ever produced.
Orgasms and addictive substances or behaviors have two things in common. They both produce an initial pleasurable experience, and both are followed by a "hangover." This is a program of neurochemical fluctuations, triggered by orgasm, which appears to continue for a week or two. The sexual satiation (post-orgasm) hangover is innate, or what we have always experienced. That's one reason many never notice its effects - they have always been there. It can be such a subtle part of you that you do not connect the dots, unless you switch to making love without it for several weeks, and then go back to sex with orgasm.
"What goes up must come down." It’s simple biology; body systems must return to balance, or homeostasis. In this case it's your dopamine (or sensitivity to dopamine) rising and falling. That can play around with your mood and, most importantly for your love life, the way in which you perceive, and treat, your partner. Perception is the key word, and it may change days after the event.
Jekyll & Hyde With conventional sex and orgasms you’re probably going in and out of these dopamine extremes. So are we saying that orgasm makes you schizophrenic and then depressed, as in the chart above? No, but it definitely can affect your behavior and mood. Reflection upon the behaviors associated with high and low dopamine may help explain how one’s lover can do the "Dr. Jekyll and Mr. Hyde" thing. (Or the Aphrodite-Medusa thing.)
Consider this: A menstrual cycle is generally 28 days of hormonal dominoes, but some women suffer from PMS often, others now and then, others don't notice it. Same thing with the orgasm cycle. It's there...and we know for sure that it lasts for at least 7 days in men, and for 15 days in both males and females of at least one other mammal. Yet the experience of those going through it can differ widely.
All of the following factors (and more, no doubt) can shape lovers' experience: How new is their romance? How much daily affection do they engage in to soothe their nervous systems? What kind of sex do they have? (Intercourse has been shown to be more relaxing over the days following than oral sex or masturbation.) How sensitive are they to particular neurochemicals? Probably no two recovery periods are identical.
Subtle or not, these changes in our feelings can lead to many of the judgments that couples routinely make: "He's not doing enough." "She's nagging me," and so forth. Your genes want enough disharmony so that both of you will welcome new mating opportunities, whether or not you actually indulge in them. Why? Increased genetic variety in your offspring. There are no sexually-exclusive monogamous mammals (or birds), even among pair-bonders. True monogamy is a ticket to extinction as far as your genes are concerned.
The mechanism that nudges mates apart is very old, because evolution keeps the traits that work in our genes' favor. This does not mean these urges work in your favor, however. Close, trusted companionship and warm affection are some of the best health insurance there is. Relationship turnover can be stressful.

The Passion Cycle: Dopamine, Prolactin, and Oxytocin

The highs and lows of dopamine are only part of the "post-sexual satiation hangover" story. At orgasm, dopamine drops like a lead balloon (at least if you're a typical male), and we lose interest, at least temporarily. Paradoxically, if you've been overstimulating yourself, you're likely be looking around for more stimulation very quickly. See Do You Need a Chaser after Sex?
A lot more happens after orgasm—although there is still much to learn. As explained, dopamine drops (and/or nerve cell receptors for dopamine decline, leaving your reward circuitry less sensitive to dopamine for some unknown period of time).dopamine drops, prolactin rises At the same time, the neurohormone prolactin shoots up. Like most hormones, prolactin has many jobs in the body. After orgasm it acts as a "sexual satiation" substance, suppressing dopamine. Dopamine is an accelerator; prolactin is a brake.
Other changes occur, too. First, enkephalins (endogenous opioids) are elevated for more than 24 hours in some brain areas, and more than two days in the hypothalamus. And this happens after one ejaculation, or after many. Opioids have been shown to inhibit oxytocin neuron activity, which may decrease feelings of satisfaction. Sexual impotence is associated with increased production of opioids and reduced production of oxytocin. Are opioids leaving lovers restless and dissatisfied over the days after orgasm?
It's understandable if you are confused about opioids, considering we said they contribute to the plesure of orgasm. In the brain it is always about specificity. So, opioids in one section of the brain may have the opposite effect in another section.
Oxytocin often surges briefly after climax (although prolactin is considered a more reliable marker of the Big O.) As oxytocin is known as the "bonding hormone," many people assume orgasm must be first-rate glue for lovers. However, like prolactin, oxytocin performs many different jobs in the body, and the orgasm surge may be related to the contractions of orgasm itself (oxytocin is also behind labor and lactation contractions). This surge also appears to trigger the rise of prolactin (a "sexual satiation" neurochemical) and penile flaccidity. Certainly, if orgasm tightly bonded lovers, we'd see very few one-night stands...and a lot more johns in love with their hookers.
Everyone's experience of this cycle is somewhat different. Numerous factors appear to affect how we experience it, such as degree of sexual surfeit, whether a partner and loving affection are present, the type of sex (intercourse or not), and, of course, individual sensitivity to pertinent neurochemicals.
Psychologists are uniquely suited to grasp the implications of this phenomenon. More than most neurobiologists, they are aware that subtle changes in feelings (even those brought on by perfectly normal neurochemical fluctuations) can be projected onto others. Projections then mold our experience of the world—and our perception of our mates—without our conscious awareness. No partner, however tolerant or attentive, can consistently soothe our discomfort, or fill a "hole" inside us, which we are experiencing because we have disrupted our neurochemical balance with too much of a good thing.
Orgasm’s fluctuating dopamine pattern, especially the lows, actually encourages addictions of many kinds because people attempt to use artificial means to manipulate ("medicate") their dopamine levels. Low dopamine (or reduced sensitivity to it) is at the heart of all cravings, whether one is addicted or not. We want our dopamine back up to normal, so we feel "right." Gary found that when he got off of the orgasm roller coaster, the results were amazing: He dropped a long-term addiction and eventually left behind prescription antidepressants, ending a lifetime of depression.
Evolutionarily, a mammal's prime choice for feeling good (without waiting out the cycle) was pursuing a novel sex partner.
Think about it. Most addictions, or use of mood-altering substances and activities, kick in during teen years, when we become sexually active. A Columbia University study found that sexually active teens use more drugs. One might think social factors alone lead to this correlation between drugs and sex, but when scientists studied hamsters, they found that sexually-active hamsters were much more susceptible to amphetamine addiction than their virgin counterparts. This research brings us to another observation. Children, or pre-teens have yet to activate this dopamine roller coaster, and they generally possess a cheerful, optimistic enthusiasm for the simplest activities. Perhaps this is due to balanced dopamine.

The Passion Cycle: Testosterone Receptors, Serotonin, and Opioids

neurochemicals fluctuate during the cycle after climaxHow long is the passion cycle on average? No one yet knows. We do know that in human males the neurochemical sequence after ejaculation is at least 7 days. (Testosterone predictably spikes briefly around day seven.) However, men and women who observe themselves carefully notice changes in mood that flicker on and off for about two weeks. Perhaps this cycle is an evolutionary remnant of an ancestor's mating season.
Among our fellow mammals, rats have been studied the most. Their limbic systems are so similar to ours that they have been called "guiding flashlights" for understanding the primitive mechanisms of our own brain. satiated rat Sexually-satiated male rats take up to fifteen days to recover their full desire for sex, although there is one way to jump-start them, which we’ll get to in a moment. (Female rats also show evidence of a 15-day cycle in the form of predictable surges of prolactin after vigorous copulation, whether or not they become pregnant.)
Research shows male rats experience a reduction in testosterone receptors for up to a week within their reward circuitry. Hormones and neurochemicals dock with receptors on the nerve cells. In this case, fewer receptors mean less sensitivity to circulating testosterone. The result is that the reward circuitry pumps out less dopamine. It's like the reward circuitry's batteries are low. If this happens in females, it would also reduce their sexual desire. Low testosterone (or decreased sensitivity to it) is associated with irritability and anger.
Serotonin and endorphin levels also rise in the reward circuitry of sexually-satiated rats. Most of us have heard that these are "happy neurochemicals," but in this part of the limbic system both function to put on the brakes instead of just producing warm, fuzzy feelings. image of nerve cell receptorsKeep in mind that sexual dysfunction is a major side effect of taking either antidepressants that raise serotonin or narcotics that mimic endorphins. When neurochemicals dampen your reward circuitry for a time, your relationship can suffer.

Dopamine and the Coolidge Effect

Humans, like virtually all mammals, are not naturally monogamous. This may not sound very romantic, but no mammals are sexually exclusive. (A few, such as humans, are socially monogamous. That is, they raise their offspring together.) It is therefore likely that our mating neurochemistry is set up to accomplish two goals. It encourages bonding so we co-parent. Yet there is also a conflicting program to push us out of those bonds—at least far enough to add a novel mate.
From chimps to rats, the same neurochemical events drive mammalian behaviors, and they are driving them to be promiscuous. Is it likely that Mr. and Mrs. Rodent are growing apart in their relationship? Could the excitement be gone from their marriage? Perhaps Mrs. Chimp spends too much money, or nags too much. Maybe Mr. Chimp watches too much football or doesn’t help much with housework. Not likely. Just like us, they have a subconscious program, triggered by mating, found in their limbic systems, which biology uses to urge them tire of their mates and move on to new mates.
regions of brain During the two weeks that the hangover from orgasm lingers, our large, rational brain proposes logical reasons to explain our relationship disharmony. Orgasm is natural…absolutely. But it may also be natural for both men and women to sour on a mate, to suddenly find a spouse unattractive, irritating, and wholly unreasonable. It may even be natural to become wholly unreasonable and thus hasten the departure of a mate.
Now we know that all of you are wondering about that sure-fire way to jump-start male rats' flagging libido. Perhaps you can already guess. All you have to do is introduce a new, receptive female. That may not be the answer you were hoping for…or perhaps it was!
Have you heard of the "Coolidge Effect?" Because that’s what we're addressing. Scientists have discovered that—after a frenzy of copulation—a male rat will lose interest in a female. BUT should a new female show up, he’ll perk up long enough to service her.1 This process can be continued until he practically dies of exhaustion—once again proving that biology doesn’t give a rat’s…hindquarters about anything but propelling genes into the future. The Coolidge Effect has been observed in every species tested, and not just in males. Lady rodents prefer to seduce new guys, too.
The Coolidge Effect just might play a role in human affairs as well. Marnia once talked with a man who had stopped counting at 350 lovers. He said, "I really don’t understand it. I lost interest in all of them sexually so quickly—and some of those women are really beautiful, too."
brussel sproutsThe Coolidge Effect is linked to your post-orgasm hangover. The reason the rat loses interest is that he’s getting a weaker and weaker dopamine surge from Partner No. 1. No dopamine surge, no interest. She is not perceived as "rewarding." The same thing happens to humans. The thrill is gone, and Partner No. 1 looks like Brussels sprouts. Now you’re primed for anything that will jack up your dopamine again. Partner No. 2 appears, and your dopamine soars. As if by magic, your blues are gone, and you have that heady feeling of anticipation, that sense of uninhibited aliveness. In short, No. 2 looks like chocolate cake.
Assuming we don't learn how to steer for lasting bonds by taming our limbic system, our reward circuitry will push us to do just what it evolved to do (once our temporary honeymoon neurochemistry wears off). We'll get less and less dopamine "reward" during sex with our current mate. Notice that this is similar to what occurs when people use drugs or gamble. They seek more and more stimulation to get the same high.
In short, feelings of sexual satiety do not promote romance—which calls into question a lot of today's relationship advice about producing bigger and better orgasms. The truth has been recognized for thousands of years. Here's a poem from the ancient Greek Anthology.
Once plighted, no men would go whoring.
They'd stay with the one they adore,
If women were half as alluring
After the act as before.
Back to our tale. What if No. 2 doesn’t show up for your tryst, and you’re left in the doldrums? Unlike rats, you have many dopamine-raising possibilities—from internet porn, gambling and alcohol, to the new dopamine agonists drug companies are producing to light a fire under slumbering libidos (not recommended, due to risky side effects).
These "fixes" make you feel better briefly, but as far as your well-being goes, they are like eating junk food—a net loss. As biologist Robert Sapolsky observed, there is a price for blasting our reward circuitry too enthusiastically in our efforts to counter the blues.
Unnaturally strong explosions of synthetic experience and sensation and pleasure evoke unnaturally strong degrees of habituation.... Our tragedy is that we just become hungrier." In short, there are advantages to steering for equilibrium initially, rather than always reaching for more stimulation to cope.
Your limbic system is not equipped to understand that there can be too much of a good thing. It just keeps rewarding you to do the same unrewarding things. A "fix" just positions you for a continuous addictive cycle of highs, more lows, and a search for more highs. Many of us spend much of our sex lives caught in this cycle—with no obvious way out.

The Power of Equilibrium

happy couple We have talked about how roller coaster levels of dopamine can break couples apart, but there’s also something holding couples together. The neurochemical that binds couples together is oxytocin, the "cuddle hormone" or "bonding hormone." Without it, we could not stay in love. Falling in love is associated with a soup of neurochemicals—like adrenaline, which makes your heart race, and, as we have mentioned, dopamine, which makes you crave your beloved, and low serotonin, which can make you obsessed with someone. But the heartwarming, loving, "gushy" aspects of love are due to oxytocin. It is the "unconditional love" hormone associated with nurturing and generous affection.
Oxytocin has various functions in the body, such as inducing labor contractions and milk ejection, but from evolutionary biology’s perspective, its main evolutionary function is to bond us to our children for life. It also serves to bond us to our mate…at least long enough to fall in love with our child so that it has two caregivers for its long childhood and adolescence.
Friendships are also built on oxytocin, and can be quite deep bonds. Yet, what happens to friendships that turn into sexual relationships? Often things change for the worse. When Harry Met Sally This change is an excellent example of the post-sexual satiation neurochemical shift or hangover kicking in.
Oxytocin and dopamine are the yin and yang of bonding and love. Dopamine furnishes the kick, oxytocin makes a particular mate appealing, in part by triggering feelings of comfort. You need both acting on the reward circuitry at ideal levels to stay in love. In experiments, if scientists block either oxytocin or dopamine, mothers will ignore their pups.
There's evidence that these two neurochemicals stimulate each other's release, so if one is low, it affects levels of the other. As sexual satiation plays havoc with dopamine, lovers can end up with a double-whammy effect on their precious emotional bonds. Low dopamine alone interferes with feelings of love, and it may reduce oxytocin levels or the brain's sensitivity to oxytocin. As things go sour, something interferes with oxytocin's bonding effects. It's likely that it's low dopamine.
The good news is that making love while avoiding sexual satiation is the loophole in biology’s plan for our love lives. This is the secret that the ancient sacred-sexuality sages stumbled upon. Making love with lots of affection, without the dopamine-driven highs and lows of conventional sex, seems to keep neurochemical levels balanced.
There's some evidence that the more oxytocin you produce, the more receptive to it key nerve cells become. This is the opposite of dopamine. In addicts, dopamine receptors start to decrease as the nerve cells protect themselves from overstimulation. Addicts then need more and more of a drug (more and more dopamine). Luckily you don’t need an ever-increasing "fix" of oxytocin to maintain the sparkle in your romance. Daily bonding behaviors can make your partner look better and better—at least to you. This is why daily affection, with less orgasm can strengthen your bond with your mate.
Oxytocin is associated with significant benefits, both emotionally and physically. In fact, oxytocin may be the answer to the question, "What is the mechanism by which love and affection positively affect our health?"
Consider the following research:
  • Oxytocin reduces cravings. When scientists administered it to rodents who were addicted to cocaine, morphine, or heroin, the rats opted for less drugs, or showed fewer symptoms of withdrawal. (Kovacs, 1998)
  • Oxytocin calms. A single rat injected with oxytocin has a calming effect on a cage full of anxious rats. (Agren, 2002)
  • This quality of oxytocin explains why companionship can increase longevity—even among those who are HIV positive (Young, 2004). dopamine high, followed by hangoverOr speed recovery: wounded hamsters heal twice as fast when they are paired with a sibling, rather than left in isolation (DeVries, 2004).
  • It may also explain why, among various species of primates, care-giving parents (whether male or female) live significantly longer. (Cal Tech, 1998)
  • Oxytocin appears be a major reason that SSRI’s [Prozac-type drugs] ease depression, perhaps because high levels of cortisol are the chief culprits in depression and anxiety disorders. (Oxytocin counteracts cortisol's effects.) (Uvnas-Moberg, 1999)
  • Oxytocin increases sexual receptivity and counteracts impotence, which may be one reason why this other way of making love remains pleasurable. (Pedersen, C.A., 2002), (Arletti, 1997)
Again, notice that oxytocin reduces cravings and increases sexual receptivity. This allows making love without orgasm to be surprisingly satisfying. The affection is always there, flowing between you and your partner.
When we tiptoe around dopamine’s highs and lows, we encourage balance and clear perception of each other. We see each other as sources of safety and pleasure, not as sources of recurring stress with brief moments of sexual pleasure. The real magic of love happens at a neurochemical level—and we can choose balance in order to foil the extremes of our genes' plans for us.

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