Memory reconsolidation is the brain’s innate process for fundamentally revising an existing learning and the acquired behavioral responses and/or state of mind maintained by that learning. In the reconsolidation process, a target learning is first rendered revisable at the level of its neural encoding, and then revi- sion of its encoding is brought about either through new learning or chemical agents (for reviews see Agren, 2014; Reichelt & Lee, 2013).
Through suitably designed new learning, the target learning’s manifes- tation can be strengthened, weakened, altered in its details, or completely nullified and canceled (erasure) through new learning during the reconsolidation process is the true unlearning of the target learning. When erasure through new learning is carried out in psychotherapy, the client experiences a profound release from the grip of a distressing acquired response (Ecker et al., 2010)
The use of chemical agents to produce erasure is described later in this article. In order to see the full significance of memory reconsolidation for psychotherapy, it is necessary to recognize the extensive role of learning and memory in shaping each person’s unique patterns of behavior, emotion, thoughts, and somatic experience. Among the many types of learning and the many types of memory, the type responsible for the great majority of the problems and symptoms that bring people to psychotherapy is implicit emotional learning—especially the implicit learning of vulnerabilities and sufferings that are urgent to avoid, and how to avoid them. These learnings form usually with no awareness of learning anything, and they form in the presence of strong emotion, which greatly enhances their power and durability (McGaugh, 1989; McGaugh & Roozendaal, 2002; Roozendaal, McEwen, & Chattarji, 2009)
For example, if a small child consistently receives frightening anger from a parent in response to the child expressing needs, the child learns not to express or even feel needs or distress and not to expect understanding or comfort from others. This learning can occur with no representation in conscious thoughts or conceptualization, entirely in the implicit learning system. The child configures him- or herself according to this adaptive learning in order to minimize suffering in that family environment. Later in life, however, this same learned pattern has life-shaping, extremely costly personal consequences.
The learnings in this ex- ample are very well-defined, yet they form and operate with no conscious awareness of the learned pattern or its self-protective, coherent emotional purpose and necessity. From outside of awareness these learnings shape the child’s and later the adult’s behavior, so the individual is completely unaware of living according to these specific learnings.
The neural circuits encoding these learnings are mainly in subcortical regions of implicit memory that store implicit, tacit, emotionally urgent, procedural knowledge, not mainly in neocortical regions of explicit memory that store conscious, episodic, autobiographical, declarative knowledge (Schore, 2003). As in the example above, the vast majority of the unwanted moods, emotions, behaviors, and thoughts that people seek to change in psychotherapy are found to arise from implicit emotional learnings, not in awareness (Toomey & Ecker, 2007).
Common clinical phenomena that express implicit emotional learnings include insecure attachment patterns, family of origin rules and roles, unresolved emotional issues, compulsive behaviors or emotional reactions in response to an external or internal trigger, panic and anxiety attacks, depression, low self-esteem, fear of intimacy, sexual inhibition, traumatic memory and posttraumatic stress symptoms, procrastination, and many others. Of course, some psychological and behavioral symptoms are not caused by emotional learnings— for example, hypothyroidism-induced depression, autism, and biochemical addiction—but it is implicit emotional learnings that therapists and their clients are working to overcome in most cases. There are also genetic or biochemical factors that may contribute to mood disturbances, but it is nevertheless the individual’s implicit emotional learnings that are largely responsible for triggering specific bouts of emotional instability (Toomey & Ecker, 2009).
It is the tenacity of implicit emotional learnings, more than their ubiquity, that is the real clinical chal- lenge. On a daily basis, psychotherapists encounter the extreme durability of original emotional learnings that fully maintain their chokehold decades after they first formed. Researchers too have observed that “A unique feature of preferences [the authors use that term to denote compelling, emotionally complex avoidances and attractions] is that they remain relatively stable over one’s lifetime. This resilience has also been observed experimentally, where . . . acquired preferences appear to be resistant to extinction training protocols” (Pine et al., 2014, p. 1).
The life-constraining grip of such patterns is the bane of psychotherapists and their clients, yet that very tenacity is a survival-positive result of natural selection. In the course of evolution, se-lection pressures crafted the brain so that any learning accompanied by strong emotion becomes encoded by enhanced, exceptionally durable synapses due to the emotion-related hormones that influence synapse formation (McGaugh, 1989; McGaugh & Roozendaal, 2002; Roozendaal et al., 2009). So durable are implicit emotional learnings that they continue to function and drive responses even during states of amnesia and are only temporarily suppressed, not erased, by the process of extinction (nonreinforcement of a reactivated, learned expecta- tion). Psychologists and neuroscientists have amassed extensive evidence that even after complete extinction of an emotionally learned response, the extinguished response is easily retriggered in various ways.
This revealed that extinction training does not result in the unlearning, elimination, or erasure of the suppressed, original learning (making the term “extinction” some- thing of a misnomer, suggesting as it does a permanent disappearance). Rather, the research found that extinction training forms a separate, second learning that competes against, but does not change, the original learning (see, e.g., Bouton, 2004; Foa & McNally, 1996; Milner et al., 1998; Myers & Davis, 2002). The learning formed by extinction training of a fear response is encoded in the brain’s prefrontal cortex, a region that can suppress and temporarily override the nearby subcortical amygdala, which plays a central role in storing and reactivating fear-based learnings (Milad & Quirk, 2002; Phelps, Delgado, Nearing, & LeDoux, 2004; Santini, Ge, Ren, de Ortiz, & Quirk, 2004; Quirk, Likhtik, Pelletier, & Pare, 2003).
Many decades of studying extinction led researchers to the conclusion that implicit emotional learnings are permanent and indelible for the lifetime of the individual once they have been installed in long-term memory circuits through the process of consolidation (reviewed in McGaugh, 2000).
There appeared to exist no form of neuroplasticity capable of unlocking the synapses of consolidated implicit memory circuits. The tenet of indelibility reached its peak influence with the publication of a research article on extinction studies by neuroscientists LeDoux, Romanski, and Xagoraris (1989) titled “Indelibility of Subcortical Emotional Memories.” The indelibility model soon entered the literature of psychotherapy when van der Kolk (1994) published in the Harvard Review of Psychiatry his seminal article “The Body Keeps the Score: Memory and the Evolving Psychobiology of Post- traumatic Stress,” in which there was a section titled “Emotional memories are forever.” The conclusion that implicit emotional learnings persist for a lifetime meant that people could never become fundamentally free of flare-ups of childhood emotional conditioning. The worst experiences in an individual’s past could at any time become reactivated and seize his or her state of mind or behavior in the present. Then, several studies published from 1997 to 2000 suddenly overturned the model of irreversible memory consolidation and indelibility.
Actually, a handful of earlier studies published from 1968 to 1982 had reported observations of the disappearance of well consolidated emotional learnings (Judge & Quartermain, 1982; Lewis, 1979; Lewis, Bregman, & Mahan, 1972; Lewis & Bregman, 1973; Mactutus, Riccio, & Ferek, 1979; Misanin, Miller, & Lewis, 1968; Richardson, Riccio, & Mowrey, 1982; Rubin, 1976; Rubin, Fried, & Franks, 1969). However, these unexplained challenges to the prevailing model of irreversible consolidation were seen as anomalies and received scant attention from memory researchers and clinicians at the time. At the end of the 1990s, however, neuroscientists in several different laboratories resumed studying the effects of reactivating an established emotional learning (Nader, Schafe, & LeDoux, 2000; Przybyslawski, Roullet, & Sara, 1999; Przybyslawski & Sara, 1997; Roullet & Sara, 1998; Sara, 2000; Sekiguchi, Yamada, & Suzuki, 1997).
Using sophisticated new techniques as well as the field’s advanced knowledge of exactly where in the brain certain emotional learnings form and are stored in memory, researchers again demonstrated the full elimination of any expression of a target learning. In addition, they demonstrated that such erasure of the learning became possible because consolidated, locked memory synapses had returned to a deconsolidated, unlocked, unstable or “labile” state, allowing erasure of the learning by chemical agents that disrupt only synapses that are in an unstable, nonconsolidated condition. The longstanding tenet of irreversible consolidation was disconfirmed. The destabilized state of deconsolidation was found to exist only soon after the target learning had been reactivated by a suitable cue or reminder. Yet, long after such a reactivation, an implicit learning is found to be once again in a stable, consolidated state. Thus the detection of a deconsolidated, destabilized state of memory soon after its reactivation implied the existence of a natural process of reconsolidation, the relocking of the synapses of a destabilized memory, returning the memory to stability. Subsequent studies found that the labile state of deconsolidation lasts for about five hours—a period widely known now as the reconsolidation window—during which the unstable target learning can be modified or erased (Duvarci & Nader, 2004; Pedreira, Pérez-Cuesta, & Maldonado, 2002; Pedreira & Maldonado, 2003; Walker, Brake- field, Hobson, & Stickgold, 2003).
If, following the reactivation and destabilization of a target learning, there is no new learning and no chemical treatment, then after its reconsolidation (that is, more than about five hours later) the tar- get learning is found to have increased strength of expression (e.g., Forcato, Fernandeza, & Pedreira, 2014; Inda, Muravieva, & Alberini, 2011; Rossato, Bevilaqua, Medina, Izquierdo, & Cammarota, 2006; Stollhoff, Menzel, & Eisenhardt, 2005).
For that reason, researchers regard reconsolidation as having two biological functions: (a) It preferentially strengthens recent learnings that are most frequently reactivated and destabilized, and (b) it allows new learning experiences to update (strengthen, weaken, modify, or nullify) an existing learning. The latter function is the one utilized for bringing about nullification and transformational change in psychotherapy. When a learned, unwanted emotional reaction is erased, there is no loss of memory of events in one’s life (as shown by Kindt, Soeter, & Vervliet, 2009, and as illustrated by a clinical example later in this article).
There is evidence that the destabilization/restabilization process and the updating/erasure process occur through different molecular and cellular processes (Jarome et al., 2012; Lee et al., 2008). With that background, we can now examine the misconceptions of the reconsolidation process listed above.
The Ten Common Misconceptions of Memory Reconsolidation.
Misconception 1: The Reconsolidation Process Is Triggered by the Reactivation of a Target Learning or Memory As noted earlier, in the reconsolidation discovery studies of 1997 to 2000, a state of deconsolidation was found to exist only soon after the target learning had been reactivated by a suitable cue or reminder. This observation was interpreted by the researchers to