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Unwiring & Rewiring Your Brain: Sensitization and Hypofrontality
Submitted by Gary Wilson and... on Tue, 12/14/2010 - 11:50
Intro to Neuroplasticity
A few resources:
- Brain Plasticity: What Is It? by Neuroscience for Kids
- Norman Doidge, MD on Pornography and Neuroplasticity from the best selling book "The Brain That Changes Itself"
- Research review by the head of NIDA, Nora Volkow, covering sensitization, desensitization and hypofrontality
Rewiring and unwiring refers to neuroplasticity or brain plasticity. Neuroplasticity is the lifelong ability of the brain to reorganize neural pathways based on new experiences. Neuroplasticity does not consist of a single type of brain change, but rather includes several various processes that occur throughout an individual’s lifetime. Brian plasticity occurs on multiple levels and includes (but is not limited to):
- Increase or decrease in myelin sheath (white matter): Covers nerve fibers to increase the speed of nerve impulses.
- Increase or decrease in number of dendrites (gray matter): These branch-like fibers are where nerve cells communicate.
- Increase or decrease in the number of synapses: Helps to determine strength of pathways, information flow, learning and memories.
- Increase or decrease in the strength of a synapse: Same as above
The above mechanisms are at work during brain development, learning, memory formation, and the development of addiction. Neuroplasticity works in two directions: it can weaken or delete old connections as well as strengthen or create new connections. In a very simplified model, the major addiction-related brain changes include:
- Desensitization: Weakening of circuits related to natural rewards (e.g. food, sex, etc.)
- Sensitization: Formation of Pavlovian memory circuits related to the addiction
- Hypofrontality: Weakening of the impulse control circuits
- Altered stress systems: CRF, Amygdala, and HPA axis
A guy rebooting:
"This will be my last attempt with this and then I'm done. I don't like porn but I like the initial high I get when I tempt myself with it (too bad after that it sucks) which at this point is better than anything I'm experiencing now."
The above short quote encompasses three of the major neuroplastic changes found in addictions: hypofrontality, sensitization and desensitization.
- “I don’t like porn” and "too bad after that it sucks" reflect hypofrontality. His more rational frontal cortex wants to recover from porn-induced ED and expects to feel like crap after a porn binge, but loses the battle to cravings. With hypofrontality, frontal cortex gray matter and functioning decrease, reducing impulse control. Now, in the tug-of-war between long-term goals and short-term relief, the urge to watch porn usually wins this battle.
- "I like the initial high" and "better than anything I'm experiencing now" reflect sensitization. Addiction pathways associated with porn use are now the easiest and most reliable way to activate the reward circuit.
- "which at this point is better than anything I'm experiencing now" is due to desensitization. Low dopamine and dopamine (D2) receptors make natural rewards boring, nowhere near as stimulating as the Internet porn to which he is sensitized.
Is sensitization the core of addiction?
Although sensitization (hyper-reactivity to cues) is covered in my videos, most viewers envision desensitization (low dopamine and low D2 receptors) as the core addiction-related brain change. Although controversial, many researchers actually view sensitization as the core change that leads to compulsive consumption. Either way, the endpoint is a familiar constellation of addiction-related brain changes.
Addiction terminology is confusing. Desensitization refers to a general dialing down of responsiveness to all pleasure...a baseline change. Sensitization refers to hyper-reactivity/excitement—but only in response to the specific cues your brain associates with your addiction.
If these two neuroplastic changes could speak, desensitization would be moaning, "I can't get no satisfaction" (low dopamine signaling), while sensitization would be poking you in the ribs and saying, "Hey buddy, I got just what you need"—which happens to be the very thing, overconsumption of which caused the desensitization. Over time, this dual-edged mechanism has your reward circuitry buzzing at the hint of porn use, but less than enthused when presented with the real deal.
You may have rebooted your brain and returned your dopamine signaling to what's normal for you, but the sensitized pathways may never entirely disappear. They are likely to weaken, however. For example, an alcoholic who has been sober for 20 years may no longer get triggered by beer commercials. Yet if he drinks a beer, his sensitized pathways would light up, and he could lose control and binge. Same thing can happen to former porn users. They need to be mindful of cues for a long time, especially powerful ones.
Here's a more technical explanation of sensitization, taken from drug use:
"Drug sensitization occurs in drug addiction, and is defined as an increased effect of drug following repeated doses (the opposite of drug tolerance). Addiction may also be related to increased (sensitized) drug craving when environmental stimuli associated with drug taking, or drug cues, are encountered. This process may contribute to the risk for relapse in addicts attempting to quit. Such sensitization involves changes in brain mesolimbic dopamine transmission, as well as a molecule inside mesolimbic neurons called Delta FosB."
In other words, the addiction has created strong neural pathways in your brain, basically memories, that are easily activated by anything associated with prior use (images, computer use, etc.) Put simply - activation of sensitized pathways equals cravings.
"Relapsed to porn once, and even though I didn't get fully erect, I could not believe the intensity of the rush I got when I clicked to the site! Very powerful excitation - tingling, dry mouth, and even trembling. I hadn't felt that kind of rush since I was at the height of puberty and got an unexpected view up a girl's skirt!"
The Mechanics: Your higher brain forms a feedback loop
So exactly how does sensitization arise in a brain that is simultaneously growing numb to normal pleasure? In simple terms, sensitization involves two very normal brain mechanisms taken too far: long term potentiation (LTP), which is the strengthening of synapses, and long term depression (LTD), which is the weakening of synapses.
Long term potentiation (LTP) is the basis of learning and memory. It can be summarized as "nerve cells that fire together, wire together." Memories arise in two steps. First, your reward circuitry signals that an experience is important by sending dopamine to your prefrontal cortex (PFC). The more dopamine the more importance your brain attaches to an experience.
Second, the PFC responds to your "This is important!" signal by (1) knitting together everything associated with the reward, and (2) forming a neural feedback loop heading back to the reward circuitry. Thereafter, any thought, memory, or cue associated with that particular reward activates the pathway, and sets your reward circuitry a buzzin'. It could be smells associated with your favorite burger joint. For a tomcat it could be the hole in the fence that led to a female in heat. For a bird it might be seeing the guy who fills the birdfeeder. It's evolutionary purpose is to help you remember the who, what, where, when and how of sex, food and rock 'n' roll.
Importantly, the feedback loop doesn't run on dopamine. It runs on glutamate. Both neurochemicals have the power to activate "Go get it!" signals in your reward circuitry. Glutamate stimulation is why porn can still ring your chimes even when your reward circuitry has stopped responding to dopamine and real partners. Reward circuit (dopamine) → PFC (associations formed) → feedback loop (glutamate) to reward circuit.
Sensitization: Creation of a super-memory
So far, the process is business as usual. Sensitization, however, transforms this normal PFC → glutamate feedback pathway to the reward circuitry into a super-memory in three steps:
- With sensitization, explicit memories (such as learning facts and events) transform into habits, which are known as implicit memories. Example: knowing how to ride a bike without thinking. Addiction-related implicit memories are like Pavlovian conditioning on steroids—very hard to ignore. When a recently sober alcoholic walks by a bar, all the sounds of laughter and smell of stale beer can whip this sensitized circuit into a frenzy, setting off strong cravings...and possibly eliminating all resolve.
- LTP strengthens the feedback pathway such that a little squirt of glutamate is all you need to fire up the nerve cells that signal, "Gotta have this now!" Sensitized pathways are a non-dopamine mechanism for activating reward-circuitry neurons—come hell or high water. This sneaky feature seems to be at the core of all additions. Traffic jam on the main dopamine highway keeping you from feeling pleasure from real sex? No problem. You have another way to get home, but it's only allowing one type of vehicle (stimulation): PORN.
- Continued use of your addiction activates a third mechanism in the sensitization process: long term depression (LTD). The reward circuitry's innate braking system (GABA) weakens, further amplifying the "Go for it!" glutamate signals. Instead of normal brain operation, which is more like city driving where you check for oncoming traffic at every intersection, your sensitized porn pathway is the autobahn. There are no traffic lights and porn is the only BMW M-5 on the road.
The autopilot thing is definitely familiar to me. It's like being possessed by a porn-crazed demon, and then once you're finished, your real self returns and wonders what the hell just happened and why you just wasted all this time looking at disgusting videos.
Same master switch for sex/food as for drug addiction
The master switch that triggers these addiction-related changes is the protein DeltaFosB. High levels of consumption of natural rewards (sex, sugar, high-fat) or chronic administration of virtually any drug of abuse cause DeltaFosB to accumulate in the reward center.
Note that addictive drugs only cause addiction because they magnify or inhibit mechanisms already in place for natural rewards. This is why the American Society of Addiction Medicine unambiguously states that food and sex addictions are true addictions.
DeltaFosB's evolutionary purpose is to motivate us to "get it while the getting is good!" It's a binge mechanism for food and reproduction, which worked well in other times and environments. These days it makes addictions to junk food and Internet porn as easy as 1-2-3.
DeltaFosB not only initiates addiction, but also helps to sustain it for a prolonged period. In fact, it hangs around for a month or two after you stop using, making relapse more likely. Moreover, the sensitized memories (and associated physical brain changes) it triggers linger for an unknown amount of time. In short, porn cues may electrify you for a long time.
Addiction neuroplasticity can be summarized as: continued consumption → DeltaFosB → activation of genes → changes in synapses → sensitization and desensitization. (See The Addicted Brain for more detail.) It appears that desensitization eventually leads to loss of executive control (hypofrontality), another major feature of addictions.
Sensitized pathways and withdrawal...ugh
Let's say you decide to make the ultimate sacrifice and stop using porn. You'll probably feel rotten for a while. Remember, your brain initially perceived your heavy porn use as a genetic bonanza. It thought you were making babies with each climax. It laid down the super-memories so you wouldn't abandon your "valuable" bevy of beauties (or whatever you were climaxing to).
Now, as you defy your brain by abstaining, your already low dopamine/sensitivity to drops further. Also, libido-squelching brain stress hormones CRF and norepinephrine shoot up. Your desensitization is in overdrive, so a real partner doesn't stand a chance. No wonder most guys experience such intense withdrawal symptoms. They're feeling less pleasure than ever in response to normal stimuli, feeling more anxious, and trying to quit the one thing that can still goose their reward circuitry. There are solid physiological reasons why addictions are so tough to beat.
Worse yet, during abstinence the sensitized "goosing" pathways grow even stronger. It's as if your pleasure center is screaming for stimulation...but only the addiction can hear the call. The branches (dendrites) on nerve cells processing addiction-related reward signals become "super spiny." This overgrowth of little nubs allows for more synaptic connections and greater excitation. It's like growing four extra pairs of ears while being stuck at a "Spinal Tap" concert. When cues or thoughts (glutamate) hammer your reward circuit, the craving scale hits eleven.
I'm finding that just random pictures in ads and stuff are setting off cravings. Even when the models are fully clothed, I really want to give in.
During recovery, it's easy to mistake an activated sensitized pathway for true libido. This is particularly true if you experience the typical radical drop in libido at some point in your recovery. During this "flatline" phase, a porn cue may still fire you up, and even trigger an impressive erection. This can fool you into thinking that porn is the cure for your sluggish libido.
The real cure is to patiently wait for structures in your brain to catch up with your new direction. Meanwhile, all other stimuli, including your partner, are less arousing.
Two months into my recovery I saw a simple frame of bare ass on an adult movie channel. Honest to god, it felt like I got injected with some kind of drug. I had the biggest urge in my penis and my mind, to put it back on. I literally ran upstairs and brushed my teeth. Had I stayed downstairs, I would have relapsed 100%. I could feel a part of me going, "WHAT THE HELL MAN? GO BACK DOWNSTAIRS!!!!!!!!!". I was shaking and panting. After 8 min of brushing my teeth non-stop, I was back to normal.
Recovery turns sensitized pathways into paper tigers
Despite their enormous power, sensitized pathways eventually lose their grip as your brain returns to normal, and everyday pleasures become more satisfying. Staring at pixels begins to register as an empty exercise, and eventually the brain allows the sensitized pathways to weaken at the same time it strengthens the pathways related to other promising rewards (such as real partners).
Here, guys describe what this shift feels like. Keep in mind that most of them have been through a tough withdrawal phase and a month (or several months) of avoiding porn/masturbation.
Guy 1) Eventually I decided to masturbate to some porn. One thing was strange: I didn't seem to get the same enjoyment from the porn as I recalled. Even finding favorite scenes didn't seem to deliver. Porn was a bit boring in some way. Even though it wasn't as "good" as I remembered it, I was still drawn back to it. Since the porn was not nearly as great as I remembered it, not going back will be easier.
Guy 2) The first time I started masturbating again, I felt my brain looking for the porn. This is going to be hard to describe...there was a spot in my brain where the porn junk went (memories, cravings, etc). When I denied the porn, I literally felt a collapse or an empty feeling in that part of my brain. Like it just did not exist anymore and my brain realized it. It was like when you clap your hands. My brain was expecting something in between the hands, but then it realized there was nothing in between except air.
Another aspect of the rewiring process involves strengthening your executive control, which resides in your frontal cortex (behind your forehead). Assessing risk, making long-range plans, and controlling impulses are under the control of the frontal cortex. The term hypofrontality is often used when describing how addictions weaken and inhibit these self-control circuits. It takes time, and consistency, to return these circuits to full working order.
A few resources:
- Hypofrontality in addiction - Easy to understand five-minute video by addiction expert
- Ominous News for Porn Users: Internet Addiction Atrophies Brains - Psychology Today post
- Two research reviews by the head of NIDA - Drug Addiction and Its Underlying Neurobiological Basis: Neuroimaging Evidence for the Involvement of the Frontal Cortex and Addiction: Decreased reward sensitivity and increased expectation sensitivity conspire to overwhelm the brain's control circuit
Functions of the prefrontal lobes:
Compared to other primates, humans possess a well developed prefrontal region. In charge of abstract thinking and analysis, it is also responsible for regulating behavior. This includes mediating conflicting thoughts, making choices between right and wrong, and predicting the probable outcomes of actions or events. This brain area also governs social control, such as suppressing emotional or sexual urges. Since the prefrontal cortex is the brain center responsible for taking in data through the body's senses and deciding on actions, it is most strongly implicated in human qualities like consciousness, general intelligence, and personality.
The tasks our prefrontal lobes perform are referred to as executive functions:
- Abstract thinking
- Motivation for goal-directed activity
- Planning and problem-solving
- Attention to tasks
- Inhibition of impulsive responses
- Weighing consequences of future actions
- Flexibility of responses (rule shifting)
- Reflective decision-making
Normally their exists a balance of power (picture to the right) between our urges/desires and our awareness of consequences of our actions
What is hypofrontality?
Hypo mean less than normal or deficient. Frontal refers to the frontal lobes, or prefrontal lobes. Alternately the terms frontal cortex or prefrontal cortex are also used. However, cortex refers to the thin outer layer of densely packed nerve cells, which appears gray. Hypofrontailty means the the frontal lobes are under performing. Structurally, this manifests as:
- Decline in gray matter (the cortex)
- Abnormal white matter (the communication pathways)
- Decreased metabolism or lowered glucose utilization
Simply put, addiction-related hypofrontality is a decline in executive functioning, which manifests as:
- Impaired decision-making arising from direct interference with reasoning, logic, and the ability to weigh consequences.
- Drives, impulses, and craving are not inhibited because of direct compromise of brain-reasoning ability.
- The mind overvalues reward, fails to appreciate risk, and fails to activate systems that warn of impending danger.
- The mind misjudges using one's addiction as “worth it” by being unable to appreciate adverse consequences.
For an addict, it's an imbalance of power: Weakened self-control systems (hypofrontality), are overwhelmed by the cravings emanating from sensitized addiction pathways and a desensitized reward circuit. In other words - your willpower has eroded.
What Causes Hypofrontality?
Examine the simplified reward circuit to the right, or this representation. Notice that the circuit starts deep within the primitive brain (VTA) and runs all the way to the prefrontal cortex. The key point is that the VTA produces the dopamine that supplies the prefrontal cortex. It is believed that a decline dopamine and dopamine D2 receptors, as occurs in desensitization, adversely affect the prefrontal cortex. Eventually, desensitization can lead to the frontal lobe changes associated with addiction: abnormal white matter, loss of gray matter, and lowered metabolism.
Much evidence exists that Internet addiction causes hypofrontality. In fact, eight recent brain studies found multiple changes when compared to control groups.
- Frontal-lobe gray matter & function decline: Study 1, study 2, study 3, study 4.
- Abnormal white matter: Study 1, study 2, study 3.
Reversing addiction-induced hypofrontality
If desensitization leads to hypofrontality and weakened willpower, then restoring reward circuitry sensitivity and dopamine levels is the key to recovery. The quickest way to reboot is to give your brain a rest from artificial sexual stimulation—porn, porn fantasy and masturbation. Most guys eliminate or drastically reduce orgasms during their reboot period.
Time heals best, but what you can do assist this process is to exercise and meditate. Aerobic exercise is the one thing that increases both dopamine and dopamine receptors. - which are related to hypofrontality. Exercise increases executive function in overweight children. Executive function is a term use to encapsulate the major functions of the frontal cortex, and obesity is related to hypofrontality. Exercise also improves ADHD symptoms while altering functioning of the frontal cortex. Exercise also reduces cravings and eases depression. One study reports that meditation increases dopamine a whopping 65%. Another study found far more frontal-cortex gray matter in long-term meditators.
Studies also show that brain training can increase dopamine involved in working memory and decrease consumption in alcoholics. As one study pointed out, one can train the prefrontal cortex as one would a muscle:
Working memory, housed in the prefrontal cortex, is strongly related to executive control. People with less working memory have poor executive functioning and training working memory improves executive control.
TECHNIQUES TO ASSIST REWIRING
If you want to stop using porn compulsively, try this technique, which is described in Doidge's The Brain That Changes Itself. Although Dr. Jeffrey Schwartz developed the technique for OCD patients, he has used it successfully with all kinds of compulsions. (OCD is closely related to the reward circuitry and its dysregulation.)
Again, some of the process is time-dependent. Said one guy after about six weeks of no PMO:
Something I've realised today is that earlier on in my reboot when a sexually related image shot into my head I found it hard to dismiss and get rid of, almost as if the part of my brain sending me the image was very strong. Now when an image shoots into my head I find it a lot easier to dismiss, and it doesn't linger around for long. It feels like the part of my brain sending these images is being weakened.
The emphasis is on what you do, regardless of how you are feeling. In other words, no matter how much resistance you feel, if you don't fall back into your old habit, you begin to rewire your brain.
Your effort speeds the process. One guy said:
You actually have to consciously take part in the rewiring. I thought I could just wait for the recovery to be done so I could do everything at 100%, but it's a good idea to help speed up the process forcefully by taking part in new productive habits even if your primal brain is not satisfied right away.
Porn addiction is a learned behavior, so your challenge is to unlearn porn use as an automatic response to stress, anxiety, boredom, loneliness and so forth. When the urge to look strikes, stall for time. Tell yourself that you won't look for at least 15 minutes, and immediately distract yourself by turning your attention to a pre-selected alternative activity. Examples: a breathing exercise, a physical exercise routine, meditation, making your favorite healthy snack, putting on some music you like, recording your thoughts in a journal, taking a cold shower or rinsing your genitals in cold water in the sink. Whatever. It doesn't matter, as long as it's something you can do immediately, and automatically, instead of looking at porn. Be prepared to repeat it as often as necessary.
If, for some reason, you can't do the alternative activity, imagine yourself doing it, step by step with full attention. See "The Power of Visualization" below.
At first turning to the alternative activity will require a mighty exercise of will. However, when you consciously direct your attention to something, it grows easier to turn your attention to it again in the future. You are actually rewiring your brain. Each time you turn your attention away from your cravings, toward your chosen activity, you strengthen the new pathway in your brain, and weaken the automatic response.
One thing I have noticed is that as time goes on, the flashbacks are from earlier and earlier porn experiences. Many that I had completely forgotten. It's like peeling back the layers.
NOTE: a former porn user will remain hyper-sensitive to any cues his brain associated with porn, for a very long time, and possibly indefinitely. This means that even a casual peek can activate your brain's old response and increase inner conflict. Stay away from porn. Resist the urge to test yourself by "just looking" to gauge how you're doing.
There are techniques for turning your thoughts away from porn below, and below "I relapsed or am in danger of relapse. What now?"
Here's how one guy contrasted a normal urge to masturbate from an addiction urge:
When I finally decided to masturbate, I did not just decide out of thin air, as though I'd missed it so much and just had to treat myself to it. Instead, I really felt this strong pull to do so, like a lot of sexual energy was coursing through me and needed an escape. The slightest touches to my genitals and even the rubbing of the sheets at night caused me to become very horny, and as a couple days went by, masturbation sounded more and more like a good idea. This is in huge contrast to feeling the urge to masturbate when addicted to porn. Your penis could be deader than a doornail, but the mere thought of all those beautiful women doing those nasty things and how it would instantly make you aroused was the true draw. It's easy to mistake that for sexual energy. I now know the difference.