Lane et al. propose a model that includes the role of learning reconsolidation in bringing about change in a psychotherapeutic setting. An important propaedeutic issue regards how we remember traumatic, aversive events in the first place. A question that has been discussed in the literature concerns the contradiction inherent in the observation that behavioral responses decrease after aversive events while individuals are still able to remember the punishing episode (e.g., Gaffan Reference Gaffan and Weiskrantz1985; Reference Gaffan2002). Such discrepancy may be resolved by considering that stimulus-response relations (e.g., the presentation of a tone evoking a lever press) and stimulus-stimulus relations (e.g., a lever press occurring when a tone and a light are presented together, but not when the tone and the light are presented by themselves [e.g., Kehoe Reference Kehoe1988]) are supported by different areas (basal ganglia and the hippocampus, respectively) and these areas are dissimilarly influenced by neuromodulation. Specifically, neuromodulation in the basal ganglia is tightly controlled by dopamine, but not other neurotransmitters (e.g., noradrenaline) that respond differently – compared to the dopaminergic system – to salient environmental events. Although dopaminergic neuromodulation is enhanced by reinforcers and not by punishers (punishers lead to a decrease below baseline in dopaminergic responses innervating the basal ganglia; e.g., Schultz Reference Schultz2007), noradrenergic neuromodulation is enhanced by both reinforcing and punishing stimulation (Sara Reference Sara2009).
In memory research, since episodes are typically characterized as unique configurations of stimuli, episodic memory can be considered one-trial learning of stimulus-stimulus relations (e.g., Ortu & Vaidya Reference Ortu and Vaidya2013). As mentioned earlier, the hippocampus is critically involved in selection of stimulus-stimulus relations and receives concurrent neuromodulation by multiple neurotransmitter systems, including noradrenaline. Importantly, the fact that noradrenergic neuromodulation affects the hippocampus, and many other areas with the exception of the basal ganglia (Sara Reference Sara2009), grants the relative independence of selection of stimulus-response relations from selection of stimulus-stimulus relations. Such arrangement allows reinforced motor behavior to be more likely to occur again in similar environments, whereas punished motor behavior is less likely to reoccur; at the same time, stimulus-stimulus relations are selected both after punishing and reinforcing stimulation, allowing episodic learning of events with both positive and negative valence. During ontogeny, the adaptive value of learning stimulus-stimulus relations correlated with punishment may be to allow unique configurations of stimuli to gain a specific stimulus function. For example, without the capability of learning stimulus-stimulus relations correlated with punishment, the organism would be prevented from learning an escape response in presence of a specific environment.
Within a psychotherapeutic intervention, emotional responses of negative valence are of crucial importance as they often represent the motivational factor leading the patient to seek therapy. Respondent, emotional responses are typically correlated with traumatic events and are often re-experienced when remembering occurs. In some cases after highly traumatic events, individuals report re-experiencing sensory-perceptual and emotional responses with high frequency during their daily lives, leading in some cases to a disruption of their daily routines. Considering post-traumatic stress disorder (PTSD) as a prototypical example of maladaptive remembering, we can link two of the PTSD recognized clusters of symptoms: (1) re-experiencing traumatic episodes and (2) avoiding stimulation related to aversive events to, respectively, (1) selection of stimulus-stimulus and (2) stimulus-response relations. Specifically, persistently reliving traumatic episodes is a form of recurrent remembering in which presentation of a subset of the original stimulus-stimulus configuration leads – presumably via hippocampal pattern completion – to a full-blown recollection of the traumatic event, including the emotional/respondent components. With regard to the second cluster of symptoms, the individual affected by PTSD typically learns to avoid forms of stimulation that may lead them to relive the traumatic events. Stimuli that are correlated with the original stimulus-stimulus configuration tend to acquire avoidance function, thereby decreasing the probability of hippocampally mediated remembering triggered by a subset of the original traumatic stimulus-stimulus configuration.
The authors describe how learning reconsolidation occurring in the therapeutic setting may lead to therapeutic advantages. This perspective should be reconciled with the fact that in disorders such as PTSD, reconsolidation by definition occurs a large number of times without necessarily bringing about any relevant therapeutic improvement. However, compared to reconsolidation occurring in nontherapeutic environments, reconsolidation occurring in the therapeutic setting may allow for novel stimulus-stimulus relations and stimulus-response relations to be selected. For example, while the traumatic episode is remembered and described, the patient is staring at the therapist who is nodding with approval. The sensory-perceptual response elicited by the face of the therapist may enter the traumatic stimulus-stimulus configuration and, importantly, some of the emotional responses of positive valence elicited by social reinforcement (the therapist's approval), may replace the emotional responses of negative valence triggered by the original episode due to the inherent incompatibility of those responses. Reconsolidation occurring in a therapeutic setting may therefore lead to different effects compared to reconsolidation occurring in a non-therapeutic setting because the therapist is in a position to arrange specific learning contingencies to modify the previously acquired stimulus-stimulus and stimulus-response relations.
Summarizing, I propose here that although a drop in the level of dopaminergic neuromodulation during traumatic events weakens stimulus-response relations leading to a decrease in the rate of the punished behavior, a concurrent increase in noradrenergic neuromodulation may lead patients to episodically learn the aversive events. Although such a mechanism makes it less likely for the individual's behavior to be punished, it also allows the person to re-experience the punishing episode, sometimes in a pathological manner as in the case of PTSD. Finally, reconsolidation occurring in the therapeutic session may lead to different effects compared to reconsolidation occurring outside therapy because the therapist can arrange specific learning contingencies to modify the previously acquired stimulus-stimulus and stimulus-response relations.
Lane et al. propose a model that includes the role of learning reconsolidation in bringing about change in a psychotherapeutic setting. An important propaedeutic issue regards how we remember traumatic, aversive events in the first place. A question that has been discussed in the literature concerns the contradiction inherent in the observation that behavioral responses decrease after aversive events while individuals are still able to remember the punishing episode (e.g., Gaffan Reference Gaffan and Weiskrantz1985; Reference Gaffan2002). Such discrepancy may be resolved by considering that stimulus-response relations (e.g., the presentation of a tone evoking a lever press) and stimulus-stimulus relations (e.g., a lever press occurring when a tone and a light are presented together, but not when the tone and the light are presented by themselves [e.g., Kehoe Reference Kehoe1988]) are supported by different areas (basal ganglia and the hippocampus, respectively) and these areas are dissimilarly influenced by neuromodulation. Specifically, neuromodulation in the basal ganglia is tightly controlled by dopamine, but not other neurotransmitters (e.g., noradrenaline) that respond differently – compared to the dopaminergic system – to salient environmental events. Although dopaminergic neuromodulation is enhanced by reinforcers and not by punishers (punishers lead to a decrease below baseline in dopaminergic responses innervating the basal ganglia; e.g., Schultz Reference Schultz2007), noradrenergic neuromodulation is enhanced by both reinforcing and punishing stimulation (Sara Reference Sara2009).
In memory research, since episodes are typically characterized as unique configurations of stimuli, episodic memory can be considered one-trial learning of stimulus-stimulus relations (e.g., Ortu & Vaidya Reference Ortu and Vaidya2013). As mentioned earlier, the hippocampus is critically involved in selection of stimulus-stimulus relations and receives concurrent neuromodulation by multiple neurotransmitter systems, including noradrenaline. Importantly, the fact that noradrenergic neuromodulation affects the hippocampus, and many other areas with the exception of the basal ganglia (Sara Reference Sara2009), grants the relative independence of selection of stimulus-response relations from selection of stimulus-stimulus relations. Such arrangement allows reinforced motor behavior to be more likely to occur again in similar environments, whereas punished motor behavior is less likely to reoccur; at the same time, stimulus-stimulus relations are selected both after punishing and reinforcing stimulation, allowing episodic learning of events with both positive and negative valence. During ontogeny, the adaptive value of learning stimulus-stimulus relations correlated with punishment may be to allow unique configurations of stimuli to gain a specific stimulus function. For example, without the capability of learning stimulus-stimulus relations correlated with punishment, the organism would be prevented from learning an escape response in presence of a specific environment.
Within a psychotherapeutic intervention, emotional responses of negative valence are of crucial importance as they often represent the motivational factor leading the patient to seek therapy. Respondent, emotional responses are typically correlated with traumatic events and are often re-experienced when remembering occurs. In some cases after highly traumatic events, individuals report re-experiencing sensory-perceptual and emotional responses with high frequency during their daily lives, leading in some cases to a disruption of their daily routines. Considering post-traumatic stress disorder (PTSD) as a prototypical example of maladaptive remembering, we can link two of the PTSD recognized clusters of symptoms: (1) re-experiencing traumatic episodes and (2) avoiding stimulation related to aversive events to, respectively, (1) selection of stimulus-stimulus and (2) stimulus-response relations. Specifically, persistently reliving traumatic episodes is a form of recurrent remembering in which presentation of a subset of the original stimulus-stimulus configuration leads – presumably via hippocampal pattern completion – to a full-blown recollection of the traumatic event, including the emotional/respondent components. With regard to the second cluster of symptoms, the individual affected by PTSD typically learns to avoid forms of stimulation that may lead them to relive the traumatic events. Stimuli that are correlated with the original stimulus-stimulus configuration tend to acquire avoidance function, thereby decreasing the probability of hippocampally mediated remembering triggered by a subset of the original traumatic stimulus-stimulus configuration.
The authors describe how learning reconsolidation occurring in the therapeutic setting may lead to therapeutic advantages. This perspective should be reconciled with the fact that in disorders such as PTSD, reconsolidation by definition occurs a large number of times without necessarily bringing about any relevant therapeutic improvement. However, compared to reconsolidation occurring in nontherapeutic environments, reconsolidation occurring in the therapeutic setting may allow for novel stimulus-stimulus relations and stimulus-response relations to be selected. For example, while the traumatic episode is remembered and described, the patient is staring at the therapist who is nodding with approval. The sensory-perceptual response elicited by the face of the therapist may enter the traumatic stimulus-stimulus configuration and, importantly, some of the emotional responses of positive valence elicited by social reinforcement (the therapist's approval), may replace the emotional responses of negative valence triggered by the original episode due to the inherent incompatibility of those responses. Reconsolidation occurring in a therapeutic setting may therefore lead to different effects compared to reconsolidation occurring in a non-therapeutic setting because the therapist is in a position to arrange specific learning contingencies to modify the previously acquired stimulus-stimulus and stimulus-response relations.
Summarizing, I propose here that although a drop in the level of dopaminergic neuromodulation during traumatic events weakens stimulus-response relations leading to a decrease in the rate of the punished behavior, a concurrent increase in noradrenergic neuromodulation may lead patients to episodically learn the aversive events. Although such a mechanism makes it less likely for the individual's behavior to be punished, it also allows the person to re-experience the punishing episode, sometimes in a pathological manner as in the case of PTSD. Finally, reconsolidation occurring in the therapeutic session may lead to different effects compared to reconsolidation occurring outside therapy because the therapist can arrange specific learning contingencies to modify the previously acquired stimulus-stimulus and stimulus-response relations.