Differentiating Implicit from Explicit Emotion

As indicated earlier priming, procedural, reflexive and habit learning are all characterized by implicit learning and memory. Conditioned eye blink and fear conditioning are reflective of early acquisition learning. Post-training hippocampal lesioning impairs volitional and intentional memory retrieval for a previously experienced conditioning session (Weiskrantz & Warrington, 1979). Therefore an intact hippocampus is needed for later recall of conditioning memory. A functionally intact medial and anterior prefrontal cortex is also needed for the ability for retrieving recent and older personally meaningful emotional autobiographical memory (Macrae, Moran, Heatherton, Banfield, & Kelley, 2004; Piefke, Weiss, Zilles, Markowitsch, & Fink, 2003; Vogt, Berger, & Derbyshire, 2003). The ease of intentional episodic retrieval is reflective of explicit memory.

I believe that emotion can best be understood as being either implicit or explicit. Implicit emotional memory, as referenced in the Traumatic Stress section of this web site, is memory that is out of awareness and can become trapped within consolidation processes, when the original memory was perceived as traumatic and overwhelming. Traumatic memory is emotionally disturbing negative memory that is perceived as painful. When chronically excluded from attention and insufficiently processed and retrieved, traumatic memory’s peripheral details become not easily remembered nor correctly temporally sequenced. Traumatic memory needs perceptual cues (traumatic triggers) that were reminiscent of the disturbing emotional memory to facilitate its recall (Ehlers, Hackmann, & Michael, 2004; Foa, Molnar & Cashman, 1995; Hembree & Foa, 2000). When traumatic memory is recalled, it has a reliving quality that is very arousing. It is characterized by increases in heartbeat, blood pressure, and skin conductance (Bremner, Staib, Kaloupek, Southwick, et al., 1999; Shin, Orr, Carson, Rauch, Macklin, et al., 2004) and the emotion of fear that may evolve into later displaced anxiety. The emotion of sadness that has been associated with loss of innocence or loss of integrity of a previous subjective self may later evolve into depression. The emotion of anger and resentment in response to feelings of helplessness in an otherwise proud and self-confident leader may evolve into temperamental volatility and aggression (Van der Kolk, 1989). Disturbing emotional memory is typically associated with amygdala activity and subcortical mediated neurophysiological arousal (Liddell, Brown, Kemp, Barton, Das, et al., 2005; Shin et al., 2004). As indicated in the Traumatic Stress section of this web site, emotionally disturbing memory that has been stifled verbal expression interferes in retrieval mediated consolidation processes.  This entraps the traumatic memory into amygdala mediated implicit processes and results in memory that is not easily and voluntarily retrievable.

Explicit emotional memory is normal memory that has been completely processed in consolidation processes. Its manifestation is evidenced in neuroimaging studies as activations in the medial prefrontal cortex. Its memory can be relatively easily retrieved requiring minimal cuing to ensure its recall (Damasio, Grabowski, Bechara, Damasio, Ponto, et al., 2000; Macrae, Moran, Heatherton, Banfield, & Kelley, 2004; Vogt, Berger, & Derbyshire, 2003). It is also characterized by lack of arousal (Bremner et al., 1999; Shin et al., 2004) as is the extinction phase of fear conditioning (Phelps, Delgado, Nearing, & LeDoux, 2004). As indicated earlier in this web site emotional extinction is likely mediated by a safe and accepting environment, which offers opportunity for verbal expression and retrieval of emotionally arousing memory.

References

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Damasio, A.R., Grabowski, T.J., Bechara, A., Damasio, H., Ponto, L.L., Parvizi, J., & Hichwa, R.D. (2000). Subcortical and cortical brain activity during the feeling of self-generated emotions. Nature Neuroscience, 3(10), 104-56.

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Hembree, E.A., & Foa, E.B. (2000). Posttraumatic stress disorder: Psychological factors and psychosocial interventions. Journal of Clinical Psychiatry, 61 Supplement 7, 33-39.

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