Sunday, May 16, 2010

Neuroscience perspective on addiction

- Multiple Code Theory

Multiple Code Theory is a psychoanalytic model of mental states that attempts to reconcile current cognitive neuroscience of information processing system with psychoanalysis (Bucci, 1997). Multiple Code Theory posits three major domains of how emotion can be processed. The symbolic system refers to an image or language. Symbols are used in semiotic sense to refer to something outside of itself. Language or image can be combined to generate infinite varieties of words or images. In the symbolic system language is presented in chunks thus its meaning can be discriminated since words are combined in many different ways to generate endless varieties of phrases. Similarly, images can also be combined to generate more complex images. Image is different from language in that auditory, olfactory or tactual modalities are employed. The symbolic system operates in the sphere of the conscious (p.174).

In contrast, the Subsymbolic system processes information in a continuous manner where information is assessed for patterns or similarities and not for discreet categorized chunks. Thus, the information in the subsymbolic system tends to be intuitive, and not well suited to be fully captured in language alone. Somatic states are primarily communicated via the subsymbolic system. The subsymbolic system mode of operation is primarily in the unconscious (p.175).

Furthermore, Multiple Code theory states that the Referential process connects the three domains; an image is especially strong in its connection potential. Image maybe connected to the subsymbolic process using its discreet and generative nature of its feature (p.178). In Multiple Code Theory, emotion schema refers to how a person is affected by interacting with other people. The term schema is meant to convey the active nature of memory and perception. Emotion schema is a type of memory formed through repeated interaction with others. Hence, repeated interaction with others, personal desires or fantasy and the response from the environment contribute the formation of emotion schema. Emotion schema is thought to transverse the domains of the symbolic and subsymbolic systems (p.195).

Emotion schema is closely associated with the Affective core that includes the bodily, sensory, visceral and motoric modes of response. Therefore, the activation of the emotion schema leads to the activation of the affective core. A person’s emotion schema can be activated in an interpersonal context and by an image or fantasy. However, it is an image that has a strong valence for activating emotion schema. For instance, a fear schema activates the affective core resulting in increased breathing, flight and change in homeostatic balance induced by an emotional factor (p.201).

Emotion schema follows a normal trajectory in development. In empathic environment, the child is able sooth itself to modulate the activation of an affective core and utilize the incorporated parental representation for comfort, safety and self-regulation. However, repeated fear schema in non-validating environment, the child’s capacity to modulate fear through the incorporation of parental representation is diminished and the result is the child’s capacity for self-care and soothing maybe compromised.

As mentioned before, the emotion schema cuts through the three domains of information processing systems. However, the emotion schema maybe disconnected from each domain due to trauma in the form of dissociation. A child may use the mechanism of dissociation in an environment of abuse from a caretaker.

The pain associated with dissociation is the result of an attempt to repair such an overwhelming affect without knowing the source of the distress. The various attempts to repair distressful affect using somatization, addiction and even psychosis are efforts to manage activated arousal level. In an effort to diminish activated affective core, the person may resort to such things like addiction which may introduce yet another level of complexity in the layer of existing pathology (p.203).

Emotion schema is anchored on contemporary neuroscience understanding. LeDoux (1998) maintains that stimulus in the brain may pass through the direct route (low road) or the cortical loop (high road). In the direct route, fear stimulus, for instance, travel the sensory thalamus through the triggering site of the amygdala and the prefrontal cortex to the emotion execution sites. The direct route initiates automatic or instinctual response of fight or freeze. The cascade of fear based information trigger motoric, visceral and somatic response (affective core) to affect changes in breathing rate, blood pressure, body chemistry as well as register changes in hand movement, vocalization and expressive functions in the face,

Fear stimulus traveling the cortical loop passes through the thalamus but bypass through the cortical association and hippocampus. This particular venue allows information to be modulated, evaluated, regulated, delayed or redirected immediate affective response. The cortical loop using the hyppocampal and related systems represent stimulus in episodic memory, which is oriented in time and space, as opposed to a general or semantic memory. Therefore, the episodic memory oriented in space and time can be processed in multiple channels including, visceral and actions (p.164) However, when the hyppocampal and related systems are compromised due to high stress, it interferes with the registration and retrieval of episodic memory such as patients with Post Traumatic Stress Disorder. Patients diagnosed with PTSD fail to remember specific source of information like a person involved, or a place or event about the trauma; their knowledge is based on narratives lacking context and detail. It should be noted, however, moderate level of stress actually enhances episodic memory (Bucci, 1997)

The referential process connects the three domains partially or to varying degrees. Therefore, therapeutic change in multiple code theory functions to transform emotion in such a way that it is integrated functionally with both symbolic and subsymbolic system (p.215).

Multiple Code Theory may elucidate the mechanisms necessary for a recovery in Narcotic Anonymous. Emotion schema activation is often precipitated by the interaction with other addicts. Interaction in the group helps to activate the affective core when individuals share personal stories. The level of activation seems to be a function of how an addict’s personal experience may resonate with others. Often painful emotion is activated at NA in the emerging mourning process.

It appears that what occurs at NA meeting is to activate affective core using each other’s personal narratives as a way of linking the symbolic and subsymbolic processes in the process of mourning. The assumption is that affect needs to be repeatedly activated in order to process and interpret painful feelings using spirituality as a referential activity. The spiritually based interpretation is an imaginative exercise of symbolizing the addict’s internal experience. Referential activity refers to the symbolizing effort of subsymbolic processes. Spirituality may help the budding symbolization effort primarily by creating a safe space in the form of acceptance and encouragement of the addict, to allow a gradual expression of affect. Subsymbolic experience may then be expressed in the form of memories, fantasies or images. Repeated attempts to symbolize help strengthen and elaborate memories, fantasies or images to the verbal system. Once these symbols become sufficiently strong, they can be discerned enough to be labeled by the addict. The addict may then verbalize feeling shamed or angered. Hence, spirituality may help in the symbolizing effort first and also helps to contextualize what is symbolized in the reflection phase. Thus, the most important function of spirituality is as a referential process perhaps in allowing the addict to find a suitable and adaptive narrative for the evoked feelings. Of course, the narrative itself is dynamic and is continually being constructed or reconstructed to reflect current needs of the addict.

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