“Brain Opioids and Social Emotions”

by Jaak Panksepp, Stephen M. Siviy & Lawrence A. Normansell


found in The Psychobiology of Attachment and Separation, edited by Martin Reite and Tiffany Field

Academic Press, Inc, 1985 – Orlando

ISBN 0125867808

Pp 3 – 49


“As infants grow and become self-sufficient, the influence of early social bonds weaken and become supplanted by bonds with peers.  At this age, brain systems encourage the young to become functioning units within social groups and the reinvigorated attachment mechanisms presumably provide an underlying basis for gregariousness and group cohesion.  (Panksepp/bo/3)”

“Fortunately, we now have enough basic knowledge concerning the brain to begin realistically seeking the neurobiological underpinnings of social emotions and thereby to decipher the sources of social bonding.  (Panksepp/bp/4)”

“…our work has been premised on the strategic assumption that all the secondary processes by which attachments are expressed depend critically on an organism’s ability to experience distress following separation from social companions and to experience comfort upon reunion.  Accordingly, we have chosen to seek an understanding of social attachments from neural circuits that mediate separation distress and contact comfort – emotions that, we assume, reflect opposite levels of activation in a single coherently operating brain organ system.  Our work is based on the additional simplifying assumption that the separation distress system exerts control over man other distinct social behaviors – including the

quality and quantity of maternal behavior,



explor- (Panksepp/bo/4) atory emergence from home areas,

social cooperation, and c

ompetition –

each of which, in turn, has feedback effects on the social affect system.  [he does not list empathy here] Further, it must be acknowledged that all these systems are embedded within circuits that control levels of vigilance, attention, and mood.  [what about arousal?] Although such reciprocal interactions yield cascades of intertwined influence and counterinfluence, theoretically guided research can now begin to tease apart coherently operating subsystems of psychobehavioral influence from this tangled skein.  (Panksepp/bo/5)”

“Considering the subjective qualities of social loss in humans (sadness, sorrow, grief, panic – in other words, various forms of psychic pain), it is reasonable to suppose that brain circuits that mediate separation distress are related to those that mediate pain.  (Panksepp/bo/5)”

“Perhaps the clearest indicator of this commonality is the characteristic behavior pattern that follows both pain and separation  — crying (more euphemistically called protest, isolation, or distress vocalizations [DVs] when observed in young animals separated from their social environments).  (Panksepp/bo/5)”

“…it is generally accepted that the analgesic property of opiates is largely due to dampening of the emotional-visceral impact of pain rather than to a reduction in the somatic-sensory discriminative aspects of noiciceptive stimuli (Wikler, 1980).  If  visceral pain and social isolation do share common evolutionary histories and affective substrates, then it might be anticipated that they will share many neurochemical controls.  (Panksepp/bo/5)”

++ Existence of opioid systems in the brain was firmly established in 1973 – he refers to Pert & Snyder, 1973; Simon, Hiller, & Edelman, 1973; Terenius, 1973.

++ their hypothesis:  brain opioids help elaborate the affective state of social comfort (Panksepp/bo/5)”

++  opioid peptides discovered in 1975 – (Cox, Goldstein, & Li, 1976; Hughes, 1975; Ling, Burgus, & Guillemin, 1976)

++ In their experiments with puppies, young guinea pigs, and chicks:

“Thus, all opioid agonists that were tested proved to be remarkably potent agents for alleviating separation distress.  All seem to be operating through a mu receptor, but the ability of the other opiate receptor types remains to be adequately evaluate.  (Panksepp/bo/6)”

My receptors are also related to mirror neurons – I need to locate this information

“The potency of the effects suggests substantial specificity for the opioid system in control of separation distress….  (Panksepp/bo/6)”

“…these pharmacological studies provided extensive evidence for the specificity of opioid systems in control of the separation distress response.  In addition, facilitation of cholinergic and serotonergic activity, manipulations that can counteract physical pain (Akil & Liebeskind, 1975; Akil & Mayer, 1972; Sahley & Bernston, 1979), yielded similar effects on separation distress.  (Panksepp/bo/7)”

“…various opioid peptides were also highly effective in re- (Panksepp/bo/7) ducing DVs….  (Panksepp/bo/8)”

“Alpha-melanocyte-stimulating hormone was the only one of the series to reliably increase DVs, and it is intriguing that this peptide coresides in B-endorphin-containing cells of the basomedial hypothalamus (Watson & Akil, 1982), perhaps providing an endogenous antagonistic influence to that exerted by opioids.  Accordingly, additional work is needed to analyze peptides arising from the N-terminal side of B-lipotrophin, as well as the other peptides of the enteric nervous systems that have recently been discovered.  (Panksepp/bo/8)”

“…the ability of mu receptor blockade to increase DVs has been replicated enough times to establish the veracity of the effect, but it is a variable one and apparently modulated by a host of factors, including age, level of social stimulation, and time of testing during the day [having to do with circadian rhythms]. …  Differential seasonal patterns of opiate responsivity have also been observed by others (Beckman, Llados-Eckman, Stanton, & Adler, 1982) and may represent changes in brain opioid sensitivities as a function of circumannual cycles of reproductive activity and social bonding.  (Panksepp/bo/11)”

“…naloxone blocks only a subset of opioid receptors – namely, the mu variety.  Perhaps concurrent blockade of others – for instance, those of the delta, kappa, sigma, and epsilon persuasions (Zukin & Zukin, 1981) – may yield more consistent results.  (Panksepp/bo/11)”

++ so, mu receptors are opioid receptors

“The general underlying principle may be that opiate receptor blockade facilitates an emotional state of social need, which establishes a central state that is highly compatible with increased crying….  Vocalizations may at times be increased by naloxone, because the underlying affective state of social need acts synergistically with brain circuitry that mediates separation calls.  (Panksepp/bo/12)”

“All of the neurochemical influences on separation distress discussed so far appear to be modulatory rather than command influences on DV circuitry.  (Panksepp/bo/16)”


“…suggests that brain opioid systems are quite active during the normal course of play (Panksepp & Bishop, 1981)  (Panksepp/bo/19)”

“Competent social behavior ultimately involves the interplay of innate instinctual processes to feel and behave in certain ways with the ability to learn.  The underlying nature of memory and learning remains to be fathomed, but it is reasonable to suppose that all the major emotional systems of the brain (see Panksepp, 1982) may be capable of mediating associate processes – whether through shared mechanisms or, as is more likely, through functionally distinct though partially overlapping ones. …  (Panksepp/op/19)”

“Our own interest in the area was spurred by the possibility that the social affect systems whose opioid property we had delineated may participate in the creation of learned social bonds.  (Panksepp/op/19)”

“…although the process of imprinting is by no means halted by mu receptor blockade, positive effects have been observed where subtle discriminations are required.  We would presently hypothesize that reduced opioid activity promotes social solicitation, and hence the instinctual approach components of imprinting, and that endogenous opioid release that may be associated with certain desirable objects provides important neurochemical feedback via which discriminations, and subsequent social choices, are made.  (Panksepp/op/20)”  [based on chick research]

“Endogenous opioids are situated ideally to reinforce social at- (Panksepp/op/20) attachments….  Not only are opioids systems probably activated during pregnancy (Houck, Kimball, Chang, Pedigo, & Yamamura, 1980) and suckling (Rivier, Vale, Ling, Brown, & Guillemin, 1977), but they may be sensitized during key times of social development (Zagon, McLaughlin, Weaver, & Zagon, 1982), such as puberty (Blank, Paneria, & Friesen, 1979; Cicero,Schainker, & Meyer, 1979; Hahn & Fishman, 1979).  Young animals could also become socially attached partially via opioid comfort derived from somatosensory contacts (Panksepp, Bean,Bishop, Vilberg, & Shaley, [Panksepp/op/20] 1980) and even directly from opioid rewards derived from mother’s milk (Brantl & Teschemacher, 1979; Hazum et al, 1981).  (Panksepp/op/22)”

“Social isolation has been dound to modify brain opiate receptor densities in mice (Bonnett, Miller, & Simon, 1976).  (Panksepp/op/22)”

“…social isolation increases voluntary opiate consumption (Alexander, Coambs, & Hadaway, 1978).  (Panksepp/op/23)”

++  What is the relationship of opioids to the pituitary?

“…it is questionable whether pharmacological doses of opiates resemble patterns of normal brain opioid activity.  (Panksepp/op/23)”

“…psychological effects of naloxone have generally proved difficult to detect in adult humans….(Panksepp/op/24)”

“The hormonal literature is also consistent with opioid participation in maternal behavior….  (Panksepp/op/24)”


both lactation and growth hormone secretion are also both under opioid control

“While the data base remains weak, it is to be anticipated that pregnancy, parturition, and the subsequent bonding process will be facilitated by opioid activity.  There are high levels of endorphins in the placenta (Houck et al., 1980; Nakai, Naoao, Oki, & Imura, 1978); (Panksepp/op/24) B-endorphin levels are elevated during pregnancy (Csontos et al., 1979); and pain thresholds are high (Gintzler, 1980).  Parturition is characterized by a large increase in plasma opioid activity (Facchinetti et al., 1982), and vaginal stimulation promotes maternal bonding (Keverne, Levy, Poindron, & Lindsay, 1983).  Considering that both lactation and growth hormone secretion are also both under opioid control (Spiegel, Kourides, & Pasternak, 1982), there is an abundance of evidence for opioid mediation of key processes during the early life of an organism.  Thus, the circumstantial evidence presently implicates opioid activity as a key ingredient in birth processes that culminate in the establishment of a warm and enduring social bond between mother and child, but essential data in support of this scenario remain to be collected.  (Panksepp/op/25)”

“The basic premise of our research program is that social affect and social bonding are in some fundamental neurochemical sense opioid addictions.  (Panksepp/op/25)”

“Hence, there should be a correspondence between, not only the psychodynamics of opiate dependence and social dependence, but also the underlying neural processes….  The key issue is whether the neural processes that mediate narcotic addiction are essentially the same as those that mediate social bonding.  (Panksepp/op/25)”

“…the unconditional attractive qualities of opiates appear to be due more to interactions with receptor fields in the ventral tegmental area (VTA).  (Panksepp/op/25)”

“…there may be global brain opioid activation in the presence of certain social stimuli (Panksepp & Bishop, 1981).  (Panksepp/op/26)”


“…studies suggest that fundamental aspects of positive social affect are not elaborated in the temporal lobes.  However, such [temporal lobe] lesions do produce substantial social disintegration, and amygdalectomized animals do not have the basic affective competence to compete and survive in the wild (Kling & Steklis, 1976).  Symptoms include a decrease in communicative gestures leading to social bonding, a loss of social rank, inappropriate sexual behavior, and a disruption in maternal behavior…However, rather than reflecting some fundamental disruption of specific social affect mechanisms, such deficits may be secondary to disruption of other sensory or emotional (e.g. fear and anger) abilities.  In any event, the amygdala is rich in opioid receptors, providing a potential opioid linkage here for control of affective processes.  (Panksepp/op/27)”

“A substantial amount of work has also been conducted analyzing effects of amygdala lesion on social behavior of rats….usual taming effects….decrease the time adult rats spend together in an open field…amount of play in young rats (Meaney, Dodge, & Beatty, 1981; white & Panksepp, unpublished data)…these effects appear to be due primarily to an inability to respond properly to social stimuli rather than to a decrease in social need or motivation.  (Panksepp/op/27)”

“…there is good reason to suppose that some fundamental aspect of social affect – for instance, the perception of social isolation – is organized in this region of the brain [cingulated gyrus]….  Social competence is also disrupted in rodents; maternal retrieval behaviors are severely disrupted by cingulate damage (Slotnick, 1967; Stamm, 1955).  (Panksepp/op/28)”

“While the cingulated gyrus appears to be relatively free of opiate receptors (Panksepp & Bishop, 1981), the area appears to be a major processing area for affective responses generated by opiate withdrawal following narcotic addiction…..  Apparently, neural circuits that mediate the perception of opioid withdrawal (and hence social withdrawal) are damaged by cingulotomy.  (Panksepp/op/28)”

“The most common emotional effects of cingulated stimulation are intense fear (Meyer, McElhaney, Martin, & McGraw, 1973), anguish, and anxiety (Obrador & Martin-Rodriguez, 1979)….  Cingulate lesions have been quite effective in alleviating (Panksepp/op/28) the psychic components of pain (Corkin, Twitchell, & Sullivan, 1979; Ortiz, 1973)….  We would presently hypothesize that the highest brain integration of social loss is elaborated by cingulated circuits.  (Panksepp/op/29)”

“Some of the highest concentrations of brain opioid receptors are found in the dorsomedial diencephalons of rats…interpenduncular nucleus and ventral tegmental area…also exhibit very high concentrations of opioidreceptors.  (Panksepp/op/30)”

“The amygdala, cingulated gyrus, and septal area play some role in the elaboration of this network [neural network important in social affect and gregariousness], although how and to what extent remains unclear.  (Panksepp/op/31)”

“…the increase in social isolation following amygdala lesions does not appear to be due simply to decreased social motivation; it may reflect the social incompetence of animals who cannot feel anger and fear, and in addition, are impoverished by a more general sensory neglect.  Of course, this is not to say that those functions are irrelevant to social competence, merely that such processes may be involved in social relations more in a secondary than a primary sense.  (Panksepp/op/31)”

“If opioid systems are of special importance in mediation of social processes, it might be anticipated that there should exist some correspondence between isolation-induced and opioid-induced bodily changes.  In other words, opioid receptor blockade should stimulate physiological symptoms of isolation distress, whereas opioid agonists should evoke those symptoms produced by reunion and contact comfort. (Panksepp/op/32)”


Strange coincidence.  I made a typo last night when naming this file, putting “bran” instead of “brain.”  This morning Cindy told me of a news story she heard yesterday where they are doing genetic modification on rice, putting human DNA in that puts a “feel good” component in that is found in mother’s milk.  They are growing the rice in Kansas where it normally does not grow so it won’t “get away.”  I just read last night about the opioids in breast milk – too strange!

They plan to put this rice product into MANY of our foods!  Frightening!


separation distress system exerts control over man other distinct social behaviors

My separation distress system could not have developed correctly.  Therefore there is something wrong in m opioid system.

I kepe thinking about eggs.  If we knew eggs would go into nearly everything important in our lives, that this ingredient was vital and necessary – but we only got our life supply in one delivery – and we needed receptacles for them –like the little dishes on the door of the refrigerator—but then we get too many eggs (opioids) and not enough receptacles (receptors) for them, then we are flooded with the opioids – but in the long run this is very inefficient.  We need more eggs, we need more places to put these “more eggs.”  This is making me feel very tired!

I would suspect that during the developmental stages that we are supposed to be deeply involved in child play, rough and tumble play, that these receptors are increasing within the brain.  Maybe that is why Jered is so reclusive!


So far, in summary:

++ opioid systems

invigorate attachment mechanisms

encourage young to be functioning part of social group

underlies gregariousness

underlies social cohesion and social bonding

underlies brain systems for mate-engaging strategies and in some species, pair-bonding

is involved with pregnancy and maternal behaviors including bonding

++ separation distress system exerts control over

maternal behavior




social cooperation


comfort at reunion – contact comfort – comfort upon reunion

protest at separation

++ these have feedback to the social affect system

social loss:  sadness, sorrow, grief, panic

crying, protest at separation and isolation

distress signals

++ all these systems are embedded in circuits that control




++ all have reciprocal interactions that “yield cascades of intertwined influence & counter influence”

++ these systems connect to the pain circuits

++ opioid system:

opiates calm separation emotions –

the affective state of social comfort –

alleviate separation distress

opiates inhibit brain circuits that mediate separation distress

activation of pituitary stress responses (both opioids and steroid) evoked by social separation

ability of opioids to facilitate natural killer cell activity in the body

“…evocation of powerful social emotions is capable of modifying a variety of physiological processes, including intensity of endogenous opioid activity, that modulate susceptibility to disease.  (Panksepp/op/34)”


“The most firmly established short-term autonomic effects produced by separation are increased, then decreased, heart rate and increased, then decreased, body temperature (Reite, Short, Seiler, & Pauley, 1981)…..  the weight of evidence is that opiate receptor blockade generally produces physiological changes similar to the aforementioned effects, whereas opioid receptor agonists generally reduce heart and respiratory rates perhaps in a manner akin to social reunion.  For a systematic analytical review of opioid effects on these physiological responses, see Szekely, 1982).  [sic, no other paren]  Body temperature effects are much  harder to interpret because opiate agonists can both incrase and decrease body temperature…..  It is also noteworthy that in humans, social interest, a state that should be related to reduced opioid activity, tends to incrase papillary size (Hess, 1975) – an effect just opposite to the well-established papillary constricting effect of opiates.  (Panksepp/op/32)”

“…opiate antagonists decrease and opiate agonists facilitate prolactin secretion (Szekely, 1982).  Conversely, in vivo oxytocin liberation induced by suckling appears to be mediated by reduced opioid activity because it is inhibited by opioids and facilitated by naloxone (Clarke, Wood, Merrick, & Lincoln, 1979; Haldar & Sawyer, 1978).  This would be consistent with the common human observation that the crying of an infant can induce milk-letdown in nursing mothers, suggesting that reduced opioid activity may instigate social caregiving behavior.  (Panksepp/op/33)”

“…the normal cycle of satisfaction derived from maternal behavior is reduced by opioid blockade.  Thus, although the perception of infant need states may be instigated by reduced brain opioid activity, the gradual satisfaction of those social needs via appropriate caregiving behaviors may be registered by gradual recruitment of opioid activity, leading to a consequent diminution of maternal behavior.  (Panksepp/op/33)”

“From the preceding perspectives, it might also be anticipated that linkages should be capable of being forged between the ability of social emotions to control susceptibility to various diseases and opioid-mediated physiological controls in the body.  For instance, loss of a loved one, whether by death or separation, is the most stressful of life events (Ruch & Holmes, 1971), and such stress can increase susceptibility to a variety of illnesses, including neoplastic ones (Rahe, McKean, & Arthur, 1967; Wyler, Masuda, & Holmes, 1971).  A link between separation distress and cellular immune competence has been established (Reite, Harbeck, & Hoffman, 1981), and such effects could be mediated via direct opioid effects on T-lymphocytes (Wybran, Appelboom, Famaey, & Govaerts, 1979) or indirectly by activation of pituitary stress responses (both opioids and steroid) evoked by social separation (Gonzales, Gunnar, & Levine, 1981; Vogt, Coe, Lowe, & Levine, 1980).  The ability of opioids to facilitate natural killer cell activity in the body has been demonstrated (Mathews, Froelich, Sibbitt, & Bankhurst, 1983), and animals that have comparatively high endogenous opioid levels exhibit reliable resistance to neoplastic disease (Thompson, Kreider, Black, Schmidt, & Margules, 1983).  (Panksepp/op/33)”

“…evocation of powerful social emotions is capable of modifying a variety of physiological processes, including intensity of endogenous opioid activity, that modulate susceptibility to disease.  In the short term, the bodily changes evoked by separation distress are presumably adaptive in warding off the potential consequences of social loss, whereas in the long run, they may become counterproductive, contributing not only to emotional but also to bodily disease.  (Panksepp/op/34)”


socioacoustic tone

“Considering the very high density of opioid receptors in the inferior coliculus (Atweh & Kuhar, 1976; Panksepp & Bishop, 1981) as well as the dependence of social bonds on acoustic signaling (Bell & Ainsworth, 1972), the possibility arises that opioids in the auditory system, in addition to providing an affective bias for certain sounds, also modulate internal speech processes that normally provide an endogenous background of affective socioacoustic tone that has become excessively externalized in certain emotional disorders.  (Panksepp/op/34)”

This makes me wonder if there is an opioid connection for me between the forced isolation and my listening – that’s all that I had…


“…reduced endogenous opioid activity, such as that presumably precipitated by social loss, may promote depression.  (Panksepp/op/35)”

“Neurochemically, a linkage between opioids and depression can be made by a consideration of the opiate effects on acetylcholine release.  One of the best established effects of opiate administration is a reduction in brain acetylcholine release (for review, see Sitaram & Gillin, 1979), and following termination from prolonged narcotic use, an explosive surge of acetylcholine activity may ensue in the nervous system (Pinsky, Frederickson, & Vazquez, 1973), which would readily explain the high parasympathetic tone that characterizes narcotic withdrawal.  This same neurochemical pattern may help precipitate both acute and prolonged social withdrawal symptoms….  The command pathway for DVs may be mediated via nicotinic-cholinergic synapses, and experimental induction of excess cholinergic activity leads to many of the obvious autonomic symptoms of bereavement.  For instance, humans treated with cholinesterase inhibitors report quite consistently bouts of sadness, tearfulness, and feelings of worthlessness, futility, and hopelessness – in other words, a generally depressed mood (Berger, Davis, & Hollister, 1979; Janowsky & Davis, 1979).  Thus, it is possible that both the short- and long-term effects of isolation distress are eventually mediated via a release of cholinergic activity that is (Panksepp/ob/35) triggered partially by reduced opioid tone in the brain.  Perhaps the acute distress may be largely mediated via nicotinic receptors, whereas the protracted phase of depression and grief may be due more to increased muscarinic tone.  (Panksepp/op/36)”

“Considering the probable importance of opioids in mediation of social affect, it might be anticipated that imbalances in the underlying systems might be especially important in development of childhood disorders….  (Panksepp, 1979a, 1981a), early childhood autism and childhood schizophrenia may partially reflect opposite poles of an imbalance in opioid systems that elaborate social affect…..  the relationships between the behavioral and physiological effects produced by low doses of opiates in normal animals are strikingly similar to those that have been reported to be present in the classical syndrome of early childhood autism described by Kanner (1943).  Both are characterized by (1) reduced pain sensitivity; (2) reduced crying; (3) reduced gregariousness; (4) reduced clinging; (5) an insistence on sameness… (6) a delay in developmental milestones; (7) increased incidence of seizures; (8) finger flicking in autistic children and increased face grooming in rodents; (9) motor flurries; and (10) changes in sensory-evoked potentials.  Indeed, treatment of animals with opiate antagonists can produce such behavioral symptoms as increased vocalization and increased social solicitation, which should be beneficial in the treatment of the core symptomology of autistic aloofness, but to our knowledge, no substantive clinical trial with either opiate antagonists or agonists has yet been attempted in such childhood disorders.  (Panksepp/op/36)”


“The basis for postulating an opioid link in the social growth of early childhood can also be derived from other developmental considerations.  Young organisms are especially susceptible to the cataleptic and analgesic effects of opiates (Caza & Spear, 1980; Huidobro & Huidobro, 1973).  Although the high sensitivity of young organisms to exogenous opiates (for extensive bibliography, see Zagon et al., 1982) may be partially due to increased brain penetrance (Kupferberg & Way, 1963), it may also reflect the fact that young organisms are more sensitive to their own opioids.  Indeed, the most potent of the opioids, B-endorphin, exists in highest levels in many brain areas prior to birth (Bayon, Shoemaker, Bloom, Mauss, & Guillemin, 1979), suggesting that in utero catalepsy may be partially (Panksepp/op/36) mediated by endorphinergic toneFollowing birth, a young organism may be liberated from such opioid bondage, and during the gradual ontogenetic shift in brain control to the weaker opioids, the organism may gradually develop heightened perceptions of social need and, thereby, increase levels of social interactions.  (Panksepp/op/37)”

most potent of the opioids, B-endorphin

If such a biochemical transition is not fully consummated, a child may be left with an excessive level of brain opioid activity, which was appropriate for in utero existence but which after birth hinders effective assimilation of a child into his or her social world.  Such a scenario, although presently only a heuristic hypothesis, provides a coherent rationale for why early childhood autism may be quite appropriately considered a syndrome of delayed development.  (Panksepp/op/37)”

What if certain social interactions must occur in order for this biochemical transition to occur – and that in cases such as mine, with such severe abuse from birth, these interactions did not happen.

“Conversely, when the protective cloak of brain opioid activity is removed too rapidly during development, the child may be left psychologically unprotected from both real and imagined social adversities, leading to a loss of confidence and trust, and a persistent social hunger. For ego protection purposes, such a psychic state may paradoxically also promote symptoms of autistic isolation, but it could be a disorder of a different kind – one that may be effectively treated by certain opiate receptor agonists.  (Panksepp/op/37)”


“Although the influence of social emotions in the governance of mental homeostasis [and physiological homeostasis] is a self-evident aspect of everyday life and profound consequences of social loss on human behavior have long (Panksepp/op/37) been observed, the biological analysis of the underlying processes remains among the most resistant and poorly developed topics in the life sciences.  This maybe because social controls were encoded in the nervous system at such an early phase of vertebrate evolution that it has come to be a well-hidden background process for the spectacular plumage of more recent developments.  (Panksepp/op/38)”

The infant cry for attention and care is an objective expression of powerful social controls that are encoded in unconditionally operative circuits of the newborn brain.  Why more effort has not been devoted to an analysis of this important phenomenon is puzzling, because work in the area should provide lasting insights into the fundamental sources of social behavior that are the shared heritage of all mammals.  (Panksepp/op/38)”

“…brain opioids are powerful influences in controlling the activity of social affect circuitry in the brain.  Endogenous opioids can inhibit separation distress circuits in all mammalian and avian species that have been studied.  (Panksepp/op/38)”

“The degree to which social comfort is elaborated b pleasure mechanisms independent of separation circuitry needs to be analyzed.  No doubt, brain opioids, although providing a provocative theoretical starting point, account for only a part of the mystery that needs to be unraveled.  (Panksepp/op/38)”

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s