Saturday, November 15, 2008

Week 7: Consciousness (Part 1)

1 a: the quality or state of being aware especially of something within oneself b: the state or fact of being conscious of an external object, state, or fact c: awareness ; especially : concern for some social or political cause2: the state of being characterized by sensation, emotion, volition, and thought : mind 3: the totality of conscious states of an individual4: the normal state of conscious life 5: the upper level of mental life of which the person is aware as contrasted with unconscious processes

CONSCIOUS (adjective; from Latin com + scire “to know”)
1: perceiving, apprehending, or noticing with a degree of controlled thought or observation (was conscious that someone was watching) 2archaic : sharing another's knowledge or awareness of an inward state or outward fact3: personally felt (conscious guilt) 4: capable of or marked by thought, will, design, or perception5: self-conscious6: having mental faculties undulled by sleep, faintness, or stupor : awake (was conscious during the surgery) 7: done or acting with critical awareness (a conscious effort to do better) 8 a: likely to notice, consider, or appraise (a bargain-conscious shopper) b: being concerned or interested c: marked by strong feelings or notions (a race-conscious society)
synonyms see aware

This week’s two main articles were fascinating, and the stuff of mental gymnastics. What constitutes consciousness? How does consciousness emerge? What role does attention play in consciousness? It occurred to me while reading that to fully understand and consider how consciousness emerges we have to be clear about what we mean by consciousness in the first place – hence the definitions above. It seems everything from perception to controlled processing is considered “being conscious,” if we are to take the definitions above. The question seems to be, however, that if we were to take a continuum of automatic to controlled processes, wherein sensory perception falls on the automatic end and focused attention falls on the controlled end, where along this continuum would we place actual consciousness?? And what role does affect play in the generation of consciousness (or the constitution of consciousness)?? But I am getting ahead of myself somewhat…first, the readings.
Thagard, P., & Aubie, B. (in press). Emotional consciousness: A neural model of how cognitive appraisal and somatic perception interact to produce qualitative experience. Consciousness and Cognition.

In the Thagard and Aubie article, a neural model of emotional consciousness is described. The authors start by stating that any model of conscious emotional experience must be able to explain differentiation between varied emotional states; integration between varying mental processes including perception, memory, judgment, and inference; intensity of emotional arousal; emotional valence (positive or negative); and the changes or shifts from one emotional state to another. They go on to suggest emotional consciousness must not be limited to either perceptions of bodily states or cognitive appraisals of one’s state, as early emotion theorists have tended to suggest through defining emotions as either somatic perceptions or appraisals. Rather, Thagard and Aubie present a neurocomputational model in which emotional representations are comprised of both perceptions and judgments. Their model is based upon the idea that mental representations are generated not only by inputs from external or internal stimuli, but also from inputs between neural populations, such that one neural population is tuned to the firing of another neural population (out of which more complex representations arise). From this perspective, neural structures are in tune with the firing patterns of other neural structures, and these patterns of firing influence each other in a dynamic fashion. This allows for a model of parallel constraint-satisfaction, wherein the activation of one structure is constrained by the activation of another when an acceptable solution has been arrived at based upon external and internal representations.
Thagard and Aubie term this the EMOCON model of emotional consciousness. Structures implicated in this process comprise both cortical and subcortical structures: dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC), ventromedial prefrontal cortex (VMPFC), amygdala, insula, hippocampus, thalamus, ventral striatum, and raphe nucleus – structures spanning brain stem to higher cortical regions. Emotional consciousness does not result from any final output from one of these areas, but instead is an ongoing dynamic process resulting from feedback between these structures. In this way, both somatic sensations and cognitive processes are integrated, each playing a role in overall emotional consciousness. In view of the explanatory criteria mentioned above the EMOCON model satisfies each of these criteria. For example, the dynamic interaction of these structures serve to explain integration of various mental process. The strength and pattern of neuronal firing within and between neural populations serves to explain variances in intensity and valence, as well as differentiation (using a neurocomputational model, they demonstrate how the strongest emotion gains full activation and suppresses other emotions, or how two emotions can become co-activated representing mixed emotions).
Thagard and Aubie posit an important role for working memory in emotional consciousness. The current, most salient representation (including internal and external perceptions and associations from long-term memory) remains active in working memory. However, because representations in working memory decay over time, if the current representation in working memory is not further elaborated, or if attention shifts, the previously represented emotion begins to decay. The authors suggest this is what accounts for shifts in emotional consciousness or emotional change. This is an interesting idea clinically – following the EMOCO model, depressive rumination or anxious worry behavior involves continual manipulation of negative or threatening information and representations in working memory which in turn serves to perpetuate the experience of depression or anxiety. To get a better sense of the importance of this process in the maintenance or severity of depression or anxiety, it would be interesting to see if lower rates of rumination or worry are associated with poorer working memory in this population, and in turn if poorer performance on working memory tasks could predict lower symptom severity.
The article goes on to present neurocomputational models of emotional consciousness, wherein final “solutions” are arrived at through explanatory coherence. Propositions are accepted through a process whereby neurons spike in parallel causing other neurons to spark in either an excitatory or inhibitory direction until the network is stabilized, representing the final solution. However, the authors suggest emotional valence also plays an important role in the acceptance of a final solution. Emotional coherence occurs when the acceptance of a proposition is swayed by the emotional valence of that proposition, such that positive emotional valence encourages the acceptance of a proposition, and negative emotional valence encourages the rejection of a proposition. This neurocomputational model provides further evidence for the integration of both cognitive and affective processes in overall consciousness.
The take-home message of this article is: emotional consciousness is the result of the integration of perception, memory, attention, and sensation, which is further colored by emotional intensity and valence. What becomes conscious is the end result of this integration, facilitated by the manipulation of this representation in working memory. This leads to a question addressed in the second article for this week – is what becomes conscious what is attended to? Or do we attend to what is conscious?

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