Desire is its own one-act play

I want to start unraveling the talks I heard, beginning with Kent Berridge’s talk. If you haven’t been following this blog or read my book, here’s some background: Berridge has made two major contributions to the study of addiction. The first is the idea that “wanting” and “liking” are independent neural systems. Wanting (or craving, as we understand it in addiction) is mostly fueled by dopamine, which is sent from the midbrain to the nucleus accumbens (NACC; or ventral striatum), a major center for goal-directed pursuit, lying in the middle of the brain, deep within the cortex and surrounded by the limbic structures. Here’s that slide once again. The NACC is represented by that yellow explosion, to convey the growth of craving over a matter of seconds or minutes. On the other hand, liking (or pleasure) is provided by — guess what? — opioids, whether they come from your local dealer or from the natural processes of your own brain (the hypothalamus produces opioids, which are critical for calming us down and relieving pain). The idea that wanting and liking are truly dissociable is pretty radical, both in psychology and in neuroscience. In the present post, I want to tell you about Kent’s recent research, as reported in Boston two weeks ago, where he demonstrates this independence — in that pristine way scientists have of breaking things down to braincycletheir fundamental components.

Berridge’s other main contribution is the idea of incentive sensitization. This is the notion that particular cues or stimuli (whether out there in the world or generated from our own fantasies, memories, daydreams, etc) become strongly associated with our drug or drink of choice. And those cues — all by themselves — activate the wanting circuit. They directly release dopamine to the NACC, so that we find ourselves suddenly beset by craving, simply by exposure to a cue. The strength of that incentive sensitization obviously increases the more often we use, because the experience itself serves to reinforce the association with the cue. But I won’t discuss this further for now.

Okay, so Kent gets up in front of this group of 15 or so people, including only two other neuro people (Davidson and me). And he’s explaining his recent research with rats, in which he’s set out to show that wanting and liking truly are separate systems. He wants to get his message across to the group, of course, but the main goal is to develop a talk that will be of interest to you-know-who. He wants, we want, the Dalai Lama to say: Hey that’s really cool! Now I get how you can want something without even liking it! For Kent, and for me, this issue gets to the heart of the problem of desire — a problem which is as central to Buddhist psychology as it is to addiction psychology.

rat-tastejpgSo here’s the experiment: The rat is “trained” to press a lever that delivers a sweet solution. This is a very typical “Skinnerian” learning paradigm. Rats love sweetness — don’t we all? — and it’s been shown that sugar speaks directly to those opioid-fueled cells in the NACC. So here’s a rat that has experienced liking which has led to wanting, in the very natural way that we are “trained” to go after rewarding experiences in life. So they are willing to press the lever many times over, as motivated by their wanting for the sweet taste — and as shown, through other studies, to depend on the flow of dopamine following that initial opioid rush.

But there’s another lever in the cage. When the rat presses it, just in the process of exploring its environment, it delivers a very salty taste. Kent is sitting in front of his computer, at the end of the table near the screen, and he looks up at us, wanting to get across how very nasty this liquid tastes to the poor rat. Imagine the taste of sea water, he says. Now imagine something that’s at least 10 times saltier — beyond the level of the Dead Sea. And I feel like I’m glimpsing the soul of this scientist. He is right there in the minds of his rats, trying to imagine — and communicate — what they are experiencing. Because that’s the necessary link here. The connection between experience and behavior. And if you’re studying it in rats rather than humans, you’d better be able to imagine what it’s like to be a rat. Anyway, the rats don’t need another trial to learn to stay away from lever #2. They hate what it gives them. There is no pleasure to be had there.

Now here comes the essence of being a good scientist: being clever enough to find the fracture point where you can split a phenomenon into its parts. We’ve got liking and wanting for lever #1. And zero liking or wanting for lever #2. Then the experimenter gives the rat a drug that reduces their blood level of sodium Slide17way below normal. They become salt-deprived. And now the punchline: The rats immediately go to lever #2 and start pressing like hell. Kent and his assistants have completely bypassed liking to get to wanting. There is clearly a high degree of wanting present, but there was never — not even once — an experience of liking that led to it.

Half the people in the room didn’t get it at all. So…the rats were salt-deprived. So they went after the salt lever? So what? Kent read their blank expressions and tried his best to convey what was so cool here. I sensed his disappointment. Who wants to go to all that trouble and have the punchline fall flat? The rats didn’t know they were salt-deprived, he explained. But the wanting circuit was immediately activated by something, some change in their biological state. It doesn’t really matter what activated it. The point is, wanting does not have to arise from liking. It’s an independent process, in mind and brain. It can arise from anything!

For me, the parallels with addiction were immediately striking. That sudden wanting, craving, compulsion that we experience for our drug of choice doesn’t have to depend on how much we liked it in the past — either the distant past or the recent past. You can crave something that you’ve never liked — just because, at some level, you need it. Granted, with drugs and booze, there is usually pleasure the first many times, then the pleasure fades, and after awhile there is no pleasure. Not even the anticipation of pleasure. The wanting comes from needing it, not from liking it. (Mind you, with tobacco, it seems you never have to experience any pleasure to graduate to craving.) So addiction is sort of like the rat experiment with a hunk of time subtracted out. After we become addicted, wanting has nothing to do with how much we do or did like it.

Following some questions and discussion, I think most of the group got it. You had to go right into Kent’s world — the world of a scientist as clever as he is determined. The point wasn’t what caused the sudden wanting. The point was simply that wanting and liking can be shown to be totally independent processes. Will the Dalai Lama get it? Will it help him, and the rest of us, understand something crucial about addiction?

Let’s hope so.

 

 

 

39 thoughts on “Desire is its own one-act play

  1. Richard Henry July 16, 2013 at 8:05 am #

    Can wanting be the same as needing? I remember when I was a full blown alcoholic and needing that drink in the morning to stop the shakes. I didn’t like it, but had to almost force it down to cure the hang over. Wanting or needing turned then to liking… after I got a few into me. I definitely know the difference between liking and needing. It was a wanting to avoid something I didn’t want… that was the hangover.

    • Marc July 16, 2013 at 9:24 am #

      I would say that wanting is exactly the same as needing — and this experiment demonstrates just that. The only difference is in how you look at it.

  2. Yuttadhammo Bhikkhu July 16, 2013 at 8:15 am #

    Interesting, but couldn’t one say the rats were acting on a ‘liking’ of whatever is the experience of sufficient sodium levels? I guess the alternative would be that they are acting on a ‘disliking’ of whatever is the experience of insufficient sodium levels. Is there any evidence that acting on disliking of negative states is qualitatively different from acting on liking of positive states?

    Anyway, neat stuff, thanks for writing 🙂

    • Marc July 16, 2013 at 10:23 am #

      But in science, parsimony is rule #1. To say the rats were acting on the basis of “liking” something they couldn’t possibly experience subjectively….is a pretty convoluted explanation, compared to saying that a “wanting” mechanism was switched on. And in any case, they had never (presumably) experienced this state before, so they’d had no chance to give it a hedonic tag. Also, “disliking” can’t possibly produce approach behavior without some intervening component.

      I should mention that Berridge and colleagues have demonstrated the wanting mechanism in dozens of other studies. The point of this study was simply to decouple wanting from liking in a single experimental context.

      • Yuttadhammo Bhikkhu July 16, 2013 at 11:02 am #

        But they had experience of satiation… I understand the theory, it just seems in this case there was a partiality trigger – surely you don’t think sodium deficiency triggers the wanting circuits directly? The rats must have ‘liked’ their former state of satiation better than the new state of deprivation, no? Wouldn’t the opioid levels be reduced in the deprived state?

        I guess I just wanted to point out that liking seems present in baseline states, and disruption of the baseline seems to lead directly to wanting for a return to the preferred state.

        • Marc July 16, 2013 at 3:42 pm #

          “surely you don’t think sodium deficiency triggers the wanting circuits directly? ”

          Yes, that’s pretty much what I do think. Interesting challenge, though. I’ll have to think about it.

          Just to return the serve, what exactly do you mean by “preferred” state? Preferred in what sense? You seem to be focused on subjective experience, while I’m more focused on a motivational thrust directed at behaviour. I’m probably not a great Buddhist, because awareness seems to me like a poor cousin of function.

          • Yuttadhammo Bhikkhu July 16, 2013 at 4:56 pm #

            Well, fair enough… I’d make a lousy scientist, because I can’t believe everything can be reduced to simple neuronal interactions and chemical reactions 🙂 What I mean by partiality, I think, is that addiction must be more complex than just turning on want/like circuits… I don’t know the science of it, obviously, but it seems like it must be something like:

            baseline -> contentment -> liking/pleasure -> addiction
            baseline disruption/pain/etc + addiction (hence liking) -> wanting

            I still think the liking plays a part, is what I’m saying, in cultivating the wanting. I think the disliking of the new state does as well, if indirectly – consider the Buddha’s words that addiction can only have a hold on a person while they are unable to find a greater happiness. It is quite evident that we are at our most addictive when we are unhappy/displeased.

            Conversely, a Buddhist monk, for example, might undergo salt or even food or water deprivation without giving rise to craving, because of the lack of addiction/partiality to the ‘baseline’ state.

            I just think there are more factors than lack of salt -> wanting. On the other hand, maybe my definition of ‘wanting’ is something more than just dopamine secretion…

            • Marc July 18, 2013 at 4:29 am #

              Of course addiction is more complex than the simple relations revealed by this study! It is highly complex, socially, psychologically, and neurally. The study just provides one piece of a small section of a very large puzzle. Still, I think it’s a valuable piece.

              Also, your’e right, wanting usually derives from liking. That’s the normal trajectory, as I said in my post. The point of this study was to peak below the natural rhythm of pleasure, relief and emotion to see some of the mechanisms that make it what it is.

  3. China July 16, 2013 at 8:53 am #

    Brilliant! You have captured exactly what I’ve been trying to expand on in some of my presentations. As an addict I try to explain how drugs turn me into a “machine”. How it is unnecessary for me to “like” the drug. How the addict brain won’t let me stop using. I can hate the drug. Hate myself. Hate everything, but the machine part of me will still exploit every opportunity to shove more of it into me. This helps a lot. To paraphrase Rick James: “Dopamine…It’s a hell of a neurotransmitter.” Wanting vs. liking explains a lot. Thanks.

    • Marc July 16, 2013 at 10:26 am #

      Hi China! That’s why I like this paradigm so much. It explains aspects of addictive behavior that just can’t be explained by other models. If I’d had more time and space I would have told you about Berridge’s experiments with lasers. He actually turns on “wanting” behavior by directly stimulating the NACC with laser light. You don’t have to like it to want it.

      • China July 16, 2013 at 11:58 am #

        Maybe you could send me a link or two. 🙂 I’ll do my search for it, but sometimes a URL to a great page helps. Really like this stuff.

        • Marc July 18, 2013 at 4:35 am #

          If you want to learn more about the independence of wanting and liking, and the role of dopamine, and the transition to addiction, I’ve got a link to Berridge’s homepage on my homepage. That’s all you need. He’s got tons of downloadable articles available there. I’d recommend a book chapter, as these are pretty accessible and they sum up the research in down-to-earth terms. There are so many to choose from. Maybe try…

          Robinson, M.J.F., Robinson, T.E., & Berridge, K.C. Incentive salience and the transition to addiction. In Biological Research on Addiction (P. Miller, Ed.), Academic Press, pp. 391-399, 2013.

          • China July 18, 2013 at 1:43 pm #

            Thanks Marc. Appreciated.

  4. Nicolas Ruf July 16, 2013 at 9:33 am #

    Two things come to mind: reinforcement can be positive (liking) or negative (relief) which can explain the sugar v. salt preference. Second, there is a lot of research linking liking with dopamine (ICSS studies galore)so we don’t need to exclude it from liking, but moving from liking to wanting shifts the dopamine surge from result to cued prediction of reward (what fires together wires together) and increases with uncertainty of outcome. So dopamine becomes motivational, motivation is highest with a 50/50 chance of success, tolerates failure, and begins to dissociate behavior from outcome. What characterizes addiction? Continuation of the behavior regardless of outcome. As I understand it, incentive sensitization means being finer tuned to the cues predicting (but not necessarily delivering) reward.

    • Marc July 16, 2013 at 10:35 am #

      Hi Nick! You’re partly right about the dopamine signal. But partly wrong. Dopamine also increases linearly with the magnitude of the expected reward, and then adjusts to the “reward prediction error”. The latter may possibly reflect “liking”, but more likely approach excitement. That was better than expected! I want more! There are several dopamine signals, each with its own function. But the signal that peaks at maximum uncertainty (which you mention) is most likely “designed” to motivate behavior. That’s when it’s most adaptive to try your hardest. Also, Kent was very clear that “liking,” which can be estimated by rats’ facial expressions and licking behavior (really!), is only produced by opioids and only in a small part of the striatum. Of course he could be wrong, but he’s got lots of neuro data to back it up.

      And your “relief” explanation is exactly what came to my mind first. But relief can only be felt following the event. So it can’t possibly motivate the approach behavior prior to salt delivery.

      • Nicolas Ruf July 16, 2013 at 5:04 pm #

        Since the rat has experienced the salt why can’t its system know what it needs and expect the relief?
        Here’s how i understand it: the better-than-expected reward results in a burst of dopamine that sets off LTP and tilts the system bias toward seeking cues predicting more of the reward. Sometimes the cue is accurate, cs leads to ur, sometimes it’s not. The stressful frustration of failure sensitizes the cue seeking and becomes motivational: this slot machine is ready to pay off; I’ve got to remember to eat before I drink. The corrupted pfc kicks in glutamate from the Ofc (“do it”) and the Acc (“keep doing it”), the sensitization kindles and internalizes, the circle closes, and the behavior becomes independent of outcome and compulsive.

        • Marc July 18, 2013 at 4:38 am #

          I think you’re loading in way too many extraneous concepts here. LTP comes later. CS-US pairing comes later. There has been no learning yet. But yes, the system “knows” what it needs, but at a level far below subjective awareness.

          • Nicolas Ruf July 18, 2013 at 11:28 am #

            Oh rats. I was hoping that my cryptic/25 words or less approach would suffice, but I guess I need to overcome my vegetative torpor and write out my understanding. For what it’s worth I think Liz is on the right track.

            • Marc July 21, 2013 at 7:26 am #

              Nice try!

  5. NN July 16, 2013 at 11:17 am #

    Marc,
    What your remarks seem not to consider is the difference between imputed wanting and experienced wanting. At first I thought it was a problem in Berridge presentation, but if you look closely at the visual aids, esp the second, it clearly says ‘Wanting’ can be intense. Do you think those quotation marks are significant?
    The want is imputed, as is the intensity.

    We can and do act without thinking. We smell smoke and run from the building. From the sudden running we infer an intense ‘want’ (desire). But perhaps nothing was experienced.

    Addicts, too, find themselves (ourselves) doing. There is no experienced ‘want’; it’s an imputed want: The observer says, “You must want that, since you just put the needle in your arm.”

    So it’s an open question, from these present data, whether the dopamine situation correlates with an experienced want. That’s how I, a non scientist, see it.

    • Marc July 18, 2013 at 4:42 am #

      Your point is interesting, NN. Yes, the “wanting” is indeed imputed. Well, isn’t everything in animal research? We don’t give them subjective questionnaires to fill out. But I don’t say that the wanting needs to be experienced in any particular way, if at all. And no, I don’t imagine they think before acting.

      Who knows what rats experience? To paraphrase Nagel, What’s it like to be a rat?

  6. JLK July 16, 2013 at 2:47 pm #

    Hi Marc

    In my last post I argued that, in the case of drug addiction, it all starts with a metaphorical “key” that fits a lock in the brain perfectly. That would be just a longer winded way of saying “like”. Therefore “like” would be a necessary precursor to ‘want”, which in turn is the precursor to full-blown addiction.

    I don’t agree with Berridge but only in a hair-splitting word-meaning way. BUT the one reason I now believe that I am wrong is….cigarettes and other tobacco products. Unless you can call trying to be “cool” around your peers “liking” or wanting” my theory does not work.To make things worse I believe cigarettes are harder to quit than alcohol (done both), the cause being that your standard cigarette affects 20 some receptors in the brain thanks to all the additives big tobacco sneaks into their products, the excuse being burning “cleaner” and staying lit for much longer when set in an ashtray.

    So “liking” and “needing” are irrelevant in this case leaving only “wanting”. Maybe this is an exception to Berridges “rules”?

    Rgds
    JLK

    • Marc July 16, 2013 at 3:36 pm #

      Great criticisms! Let me give it some thought…..

    • Marc July 21, 2013 at 7:40 am #

      Hi again. I pretty much equate wanting and needing. It seems that the difference is always somewhat arbitrary, so I just don’t go there. But I do think that the “key in the lock” model brings in a neat twist. And I really don’t know if it does fit with Berridge’s liking/wanting distinction. There are plenty of examples of people who, after their first shot of meth OR heroin, say: that was the best experience of my life. See “Beautiful Boy” for an example with meth, and see — “The ___ Story”, sorry the name escapes me for now, for an example with heroin.

      But your point about tobacco is a clear case, in my view, of the development of wanting (needing) with very little if any “liking”. Well, unless you parcel in the social pleasure of thinking that you’re looking cool — or maybe the experience of sucking something in. Otherwise, cigarettes get pretty straight to wanting. And, as you say, cigarettes are harder than booze to give up. In fact, 50% of smokers will not quit for good until 30 years after their first puff, whereas for drinkers the 50% rate comes at 16 years. These fascinating stats come from a recent paper by Gene Heyman: http://www.annualreviews.org/doi/abs/10.1146/annurev-clinpsy-032511-143041?journalCode=clinpsy

  7. Liz July 16, 2013 at 2:58 pm #

    The interesting question about these double-dissociation studies, for me at least, is that Berridge is equating “wanting” something because it has been previously associated with a reward and “wanting” something because it is a NEGATIVE reinforcer and will remove an aversive state. Going back to the drug addiction versus compulsive disorder debate, do you think this evidence suggests that drug use and OCD-like behaviors are more similar than we like to think? Perhaps they are similar at the unconscious level, but the added layer of complexity provided by the cortex makes the compulsive seeking of positive versus negative reinforcers dissociable?

    Also, out of curiousity, did Berridge indicate that NAcc DA was associated with “seeking” the salty substance in the salt-deprived state? I cannot remember if those studies have been conducted yet.

    • Marc July 21, 2013 at 7:24 am #

      These are great points of discussion. First of all, I wrote a post about OCD as the sort of paradigm case (granddaddy) of addiction, not long ago: https://www.memoirsofanaddictedbrain.com/connect/the-common-denominator-of-all-addictions/ There is evidence that similar brain regions (esp dorsal striatum) are activated in OCD patients and in addicts anticipating their drug of choice. And the behavioral parallels are pretty clear, as you suggest. But in both cases, there is only negative reinforcement, the anticipated cessation of an aversive state. No positive reinforcement on the horizon. So I don’t know what you mean by “compulsive” seeking of a positive state. The simple view: if it’s compulsive, it doesn’t require a positive reward to motivate it. But if I get what you mean, it does seem possible to feel compulsion and reward anticipation at the same time. I’m pretty sure that’s what I’m feeling two minutes before my first taste of a single-malt scotch following a stressful day. And, apparently, both the ventral (NAcc) and dorsal striatum are coactivated in advanced addiction — that may underlie this very combination. This paper by Everitt and Robbins seems to be the latest word: http://www.ncbi.nlm.nih.gov/pubmed/23438892 But I haven’t read it carefully yet.

      As to your last point, I don’t think this has been tested. Berridge likes to point to his recent studies in which the extended amygdala is activated by a laser to promote states of intense seeking (presumably wanting). He presented this work in Boston too. But….that’s a pretty big region, in which the NAcc is a small component.

  8. Denise July 16, 2013 at 10:23 pm #

    At the risk of oversimplifying, would the following be an illustrative example of the separation between wanting and liking: when you have a feeling of wanting something but you don’t know what. For example, standing in front of the refrigerator, wanting something, but nothing seems appealing. Or, like me, a somewhat controlled shopping junkie, I’ll scroll through screens and screens of websites like the store, Anthropologie, or Sundance Catalogue, feeling a desire for something, but not specifically looking for anything. Sometimes I’ll buy, sometimes I won’t. Obviously I’m not lacking something physical the way the rat needed salt. On the other hand, maybe in my brain there’s a shortage of some neurotransmitter or an excess of another (dopamine?)?

    • Marc July 21, 2013 at 7:46 am #

      Fascinating idea. I really don’t have an answer. I would imagine that this generalized state of wanting something is probably very different from Berridge’s classic “wanting” mechanism. For one thing, it completely escapes any kind of learning. In other words, you can’t get Incentive Sensitization building up for the consumption of….I know not what. Also, classic wanting is highly focused on a specific target. One of my favourite examples is being in love. For Romeo and Juliet, there was nothing abstract about it.

      Yet the state you describe is certainly familiar. Anyone else have any ideas about this?

  9. Joe S July 17, 2013 at 2:57 am #

    Hey Marc
    I think I’m starting to understand this but I’m not sure. I have two question. in one of his papers Barridge describes incentive sensitization as an actual change in certain
    neurons in certain brain circuits linked to wanting. but he poses a question as to whether normal reward behavior such as food sex social interaction produce the same changes. do we now know this is true or untrue? second I’m not sure that the use of facial expressions in mice is a definitive measure of wanting. could you edify me on this question? thanks again love your blog keep u3p the good work.

    • Marc July 21, 2013 at 7:56 am #

      HI Joe. You’re exactly right: incentive sensitization depends on synaptic changes (which are changes in the actual tips of the fibers emitting from neurons) somewhere along the route between the perceptual cortex and the nucleus accumbens (striatum). I asked him if he knew where these changes were most likely to occur, and he answered that the jury is still out. But some are very likely to be the neurons in the ventral tegmental area (VTA), which is the nucleus that releases dopamine to the striatum.

      But I’m sure the answer to your question is YES. Food, sex, and all the natural pleasures, must produce wanting by the same mechanism. It’s simply a case of synaptic alteration among the regions responsible for goal pursuit. These changes must underly the development of “wanting” for any rewarding goal.

      As for rat facial expressions, the connection is with liking, not wanting. See my next post for an example. I don’t think “wanting” has a particular facial expression in humans or other animals. I remember feeling surprised and bothered about this when I was deep into emotion theory. Most “basic emotions” have clear facial and/or postural signs. Yet, desire, one of the most common and most basic emotions, does not!

  10. NN July 17, 2013 at 11:23 am #

    http://health.nytimes.com/health/guides/disease/anemia/print.html
    https://www.medify.com/insights/article/1914087/pica-and-iron-deficiency-anaemia
    http://www.wishard.edu/health-library/Content?contenttypeId=19&contentId=iron

    A child ‘wants’ to eat dirt or clay; a premenstrual woman craves red meat. Possibly an iron dificiency is the cause,
    for administration of iron, in some cases at least, causes cessation of the compulsive behavior.

    We might say the body ‘wants’ iron. The mental representation, if any, MIGHT be of something
    which contains or might contain iron. That would be what the person says she wants.

    There are interesting parallels with the compulsive patterns of use of addictive substances.
    Does the body ‘want’ a certain neurotransmitter or neurochemical, such as noradrenaline?
    What shape does the experienced ‘want’ take? Is the addiction to (compulsive dosing of)
    methamphetamine the person’s answer to the biochemical need?

    It might also be mentioned that the ‘want’ can be off target and harmful. Ingestion of some items,
    say, laundry starch, may exacerbate the iron problem. If the addiction is at least
    partly *caused* be some deficiency, does the person end up exacerbating that
    by his drug of choice, a kind of vicious cycle? There is another parallel.
    Ingestion of dirt can cause intestinal blockage. Ingestion of alcohol can hurt
    or ruin the liver. So the person’s attempt to remedy has some substantial
    ancillary ‘cost’ or risk.

    Sometimes the ‘want’ is simply off target: An example is eating ice when iron deficient.
    https://www.medify.com/insights/article/11262806/rapid-regression-of-prolonged-pagophagia-after-treatment-of-iron-deficiency

    • Marc July 29, 2013 at 7:55 am #

      I’m not sure exactly what your point is, but you seem to be saying that “wanting” or “craving” can be for many different kinds of things, conscious or not, and can be activated by goals that are either helpful or harmful — or possibly both. I don’t think you’re presenting this as a counter-argument, but rather as an elaboration.

      Indeed, these examples seem to point to a wanting mechanisms that is highly general — so that it can function in relation to a great variety of goals. But that is the way with many of our psychobiological mechanisms: learning, imitation, inhibition, and also the emotions themselves, including anxiety and shame.

      It seems that nature, being as economical as possible, provided multipurpose (or “stretchable”) mechanisms wherever possible.

  11. Valeria July 18, 2013 at 12:52 pm #

    Hi Marc,
    really intreresting argument!!! I think Berridge’s work shows that you can want something
    1) whithout liking it
    and /or
    2) because you need it.
    The first point could explain the ‘hijacked brain’ in addiction and why an addicted person continue using the drug without his own will, infact he doesn’t like it anymore!!!
    the second point, can explain the deficency in feeling reward because the neuroadaptation of the reward circuitry and the need to take drugs to try to restore the reward level to the normal state.
    So addiction could be seen as a desire problem…
    Now I”ll write something provocative…Salt deprivation is like sugar deprivation that is diabetes, and diseaseis a disease!!!So Volkow and Koob could confirm their point of view…while Buddhist can say that wanting (crawing) and need have the same root ‘the inner emptiness’…You know I think the same…
    Looking forward the next post.
    Many thanks

    • Marc July 29, 2013 at 8:00 am #

      HI Valeria, Yes, this is Berridge’s answer to the hijacked brain idea. Of course he doesn’t use that phrase. But that’s because he doesn’t need it. It’s perfectly obvious that “desire” overtakes us, bends us to its own will — very often, whether we’re “addicts” or not.

      But your diabetes example is provocative. Do diabetics actually crave sugar when their levels are too low? Or insulin when their levels are too high? I don’t know. But if they did, it would be certainly be consistent with the behavior of these rats.

  12. Persephone July 22, 2013 at 6:16 pm #

    So is there an anxiety related link here? Someone craves something that will calm them, they take the step to ingesting it? Sorry, just what I was thinking.

    • Marc July 29, 2013 at 8:01 am #

      There might be, but I don’t think it’s necessary at all. What I got from the study is simply that “wanting” can work independently of “liking”.

      • Persephone July 30, 2013 at 9:08 am #

        That’s what I got as well, I suppose I was thinking of the degree to which we’re trained to ingest something to deal with emotions. Otherwise, it does remind me of my own diet…lol…I assure you, I didn’t “like” raw spinach last year, I just couldn’t stop eating it.

  13. Thanh Chau July 23, 2013 at 7:17 pm #

    Hyponatremia is a diseased state as well as craving. There are probably many levels of “normal” baseline states for different people in a group (a bell distribution curve, maybe).
    Addicted brain is organically different from that subject’s pre-addicted brain, physiologically, anatomically and functionally.
    Diseased state is a warning of harm to a system and survival instinct will switch on many behaviours to rescue this system, be it a brain, a body or a mental state.

    To tease out different circuits with a hope of “cure” for an addicted brain is very commendable and full of compassion for sick fellows of the group.

    • Marc July 29, 2013 at 8:04 am #

      Yes, but the concept of “disease” isn’t necessary for the mind or the body to go into a repair mode. We try to fix ourselves when we’re tired, or angry, or depressed, or hungry, etc, etc. So I try to keep the idea of addiction somewhat free of the disease label — though for others, addiction is indeed a disease.

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