Memory reconsolidation, emotional arousal, and the process of change in psychotherapy, Lane, Ryan, Nadel, and Greenberg (2015)

Lane, R. D., Ryan, L., Nadel, L., & Greenberg, L. (2015). Memory reconsolidation, emotional arousal, and the process of change in psychotherapy: New insights from brain science. Behavioral and brain sciences, 38, e1.

Emotions

Emotional arousal is an essential component of effective therapy.

Considerable research has shown that “the explicit, conscious reported experience of emotion is an important ingredient in therapeutic success” in many different therapies, including therapies “such as behavior therapy and CBT that do not in theory explicitly rely on such experiences.” See pages 8 and 15-17.

Catharsis alone is not enough.

Freud and Breuer argued that an individual developed psychological symptoms when they experienced a traumatic event but did not express their feelings. The key to healing, they hypothesized, was emotional abreaction or catharsis. “Research shows that emotional catharsis alone (e.g., beating a pillow) does not attenuate or dissipate affect but rather leads to a heightening of it (Bushman 2002).”

Memory reconsolidation is the key to understanding effective emotional arousal in therapy.

Background information

Cognitive functions

All cognitive functions — perception, problem-solving, memory, emotions — contain both implicit and explicit processes. 

(1) Implicit memory “refers to the impact of prior experience on subsequent behavior in the absence of explicit recall or awareness of that prior experience.” 

(2) Implicit learning involves “the acquisition of complex sets of rules that govern predictions (Reber 1989), allow categorization of novel objects and concepts (Seger & Miller 2010), and guide social interactions (Frith & Frith 2012). Importantly, this learning occurs regardless of whether the individual is explicitly aware of the rules that have been acquired or that learning has even taken place.” 

(3) Implicit emotions are “automatic bodily responses that are unconscious in the sense that they are not associated with awareness, are not consciously symbolized and are not known (but could include the unattended conscious or phenomenal experience of the bodily state).” (“Emotion can be understood as an organism’s or person’s mechanism for evaluating the degree to which needs, values, or goals are being met or not met in interaction with the environment and responding to the situation with an orchestrated set of changes in the visceral, somato-motor, cognitive, and experiential domains that enable the person to adapt to those changing circumstances.”)

Memory

(1) Emotion, stress, and memory. Both emotional arousal and physiological stress influence memory. For example, when we have an intense emotional experience during an event, we will be more likely to recall the memory vividly. This happens because during emotional arousal there is an “increased physiological interaction between the amygdala and hippocampus, which leads to enhanced encoding and long term consolidation of emotionally arousing information.” 

(2) Dynamic memory. After a memory is formed, it undergoes a process of stabilization or consolidation, which makes it “more resistant to interference from similar experiences, and more likely to be recollected later on.” However, the memory does not then become immutable, and it will undergo revision and reshaping when it is later recollected.

Memory Reconsolidation

Nadel and Moscovitch developed a theory of memory consolidation known as multiple trace theory (MTT). They argued that “the establishment of long-term memories involves a lengthy interaction between the hippocampal region of the medial temporal lobes and neocortical regions.” The “hippocampus remains an integral part of the memory trace and is thus always involved in retrieval of long-term episodic memories regardless of the age of the memory.”

MTT holds that whenever an episodic memory is retrieved, “a new encoding is elicited, leading to an expanded representation or memory trace that makes the details of the event more accessible and more likely to be successfully retrieved in the future.” Every time a memory is retrieved and re-coded, “an updated trace is created that incorporates information from the old trace but now includes elements of the new retrieval episode itself – the recollective experience – resulting in traces that are both strengthened and altered. This altered trace may incorporate additional components of the context of retrieval, new relevant information pertaining to the original memory, or even new information that is inadvertently (perhaps incorrectly) generated during the act of retrieval, as in the case of the flashbulb memories described earlier.”

And so “MTT holds that memories are not a perfect record of the original event but undergo revision and reshaping as memories age and, importantly, are recollected. The reconsolidation process, by this view, results in memories that are not just stabilized and strengthened, but are also qualitatively altered by the recollective experience.”

Rat studies have validated the theory of memory reconsolidation. Nader et al. (2014) conducted a study in which rats were presented with a tone paired with a shock. Several days later the rats were presented with a tone not paired with a shock. The rats were then divided into two groups. The rats in the first group then had anisomycin, a chemical that “blocks the consolidation of fear memories,” injected into their amygdalas, while the rats in the second group had saline solution injected into their amygdalas. The rats in the first group did not exhibit fear responses when they subsequently heard the tone. This experiment suggested that “fear memories undergo reconsolidation every time they are retrieved, and that this reconsolidation process can be disrupted, apparently eliminating the previously well-learned fear responses.” Studies have also demonstrated memory reconsolidation in humans. 

For human studies, see Hupbach article below.

MTT can be used in therapy. “During therapy, patients are commonly asked to recall and re-experience a painful past event, often eliciting a strong emotional reaction. If the psychotherapy process leads to a re-evaluation of the original experience, a new, more adaptive and perhaps more positive, emotional response may ensue. The corrective experience occurs within a new context, the context of therapy itself, which can then be incorporated into the old memory through reconsolidation. It is important to reiterate that MTT suggests this process is not simply attributable to a new memory trace being created, but that the original event memory itself is transformed in fundamental ways. It is conceivable that once this transformation has taken place the original memory, including the associated emotional response, will no longer be retrievable in its previous form.”

Put differently, the authors are proposing a form of corrective emotional experience. This concept was first introduced by Franz Alexander and Thomas French. Change, the current authors argue, requires (1) “activating old memories and their associated emotions” and (2) “introducing new emotional experiences in therapy enabling new emotional elements to be incorporated into that memory trace via reconsolidation.” Patients are often asked “to experience strong emotions, elicited by the recollection of a past event or other precipitating cue. By activating old memories and their associated emotional responses in therapy, new emotional elements can be incorporated into the memory trace.”

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Hupbach, A., Gomez, R., Hardt, O., & Nadel, L. (2007). Reconsolidation of episodic memories: A subtle reminder triggers integration of new information. Learning & memory, 14(1-2), 47-53.

Consolidation theory holds that, after memories are encoded, they are labile for a short period of time. Reconsolidation theory holds that when memories are reactivated, they return to a labile state and can change.

Walker et al. (2003) demonstrated that procedural memory undergoes reconsolidation. “Participants were trained on a procedural mo-tor-skill task that involved finger-tapping a simple sequence (e.g., 4-1-3-2). Twenty-four hours later they briefly rehearsed the se-quence (reactivating it) and learned a second sequence (e.g., 2-3-1-4). When tested on Day 3, accuracy performance for Sequence 1 was significantly impaired in comparison to a group of partici-pants who did not rehearse Sequence 1 before learning Sequence 2. This shows that the reactivation of the memory for Sequence 1 on Day 2 destabilized it such that a competing motor pattern could interfere.”

Hupbach et al. demonstrated that episodic memory undergoes reconsolidation. In their study, college students were divided into two groups. On Day 1, students were individually asked to memorize 20 different items. On Day 2, half of the students were asked to remember the items they had seen the first day and were then asked to memorize 20 new items, while the other half were not asked to remember the previous day’s items but to simply memorize the 20 new items.

On Day 3, the students were asked to remember as many items as they could from the first day. Both groups remembered the same number of items from the first day. However, students in the treatment group “intermixed a high number of objects from List 2 in their recall of List 1. In contrast, participants in the no-reminder group showed few intrusions.”