Consul wrote: ↑July 8th, 2021, 8:44 pm(For example, the neuroscientist Joseph LeDoux, a leading expert on emotions, rejects [Solms' brainstem theory].)
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"As I argue in this book, subcortical circuits provide nonconscious ingredients that contribute to feelings of fear and anxiety, but are themselves not the source of such feelings. The main difference between my view and Panksepp’s is, therefore, whether subcortical systems are directly responsible for primitive emotional feelings or instead are responsible for nonconscious factors that are integrated with other information in cortical areas to give rise to conscious feelings. What Panksepp calls cognitive feelings are, I maintain, what feelings are. The subcortical states are, as he also says at times, “truly unconscious” and thus not feelings at all. They are, in my view, nonconscious motivational states.“"
(LeDoux, Joseph.
Anxious: Using the Brain to Understand and Treat Fear and Anxiety. New York: Viking, 2015. pp. 129-30)
"SUBCORTICAL THEORIES OF CONSCIOUSNESS
The views of consciousness discussed above are highly corticocentric. Some argue against this approach. For example, it is known that decortication does not eliminate purposeful goal-directed behavior in animals. But one could just as easily argue that this means that consciousness is not required for goal-directed behavior. Indeed, as discussed in previous chapters, consciousness is not a requirement for using incentive stimuli to guide instrumental (goal-directed) behavior, or for behavior to be reinforced by its consequences. Another point that is used to argue against cortical views of consciousness is the fact that children born without a cortex can still exhibit conscious awareness. However, much evidence has demonstrated that malfunctions of brain development can be compensated for, and when this happens, all rules are off in terms of what goes where in the brain. The genetic program that builds the brain typically follows a plan that puts functional circuits in assigned places. But when that plan is disrupted, key functions are wired into alternative locations. If the visual cortex is damaged, for example, vision is handled by what is normally the auditory cortex. If the left hemisphere (the language hemisphere in most people) fails to develop, the right hemisphere takes over many language functions. The survival of consciousness in the absence of a normal cortex does not mean that consciousness is normally managed by subcortical areas.
In this context we should also revisit the theories of emotional consciousness by Damasio and Panksepp discussed in the previous chapter. Recall that they distinguished a primitive form of consciousness and a cognitive form. The primitive forms they postulate are in essence subcortical hypotheses of first-order phenomenal consciousness since they propose that these subcortical states do not have to be cognitively accessed in order to be consciously experienced as emotions. Then, through cognitive consciousness and its tools (such as working memory, attention, memory, and language), these primitive states can be elaborated and accessed, and thus consciously experienced, as full-blown emotions.
Panksepp and his collaborator Marie Vandekerckhove describe subcortical states of affective consciousness as “implicit procedural (perhaps truly unconscious), sensory-perceptual and affective states organized at subcortical neuronal levels.” But they also argue that subcortical emotional states “give us a specific feeling of personal identity and continuity without explicit reflective awareness or understanding of what is happening.” The states are thus implicit (“truly unconscious” and lack “reflective awareness”) and, at the same time, are also consciously experienced (“give us a specific feeling”). It’s hard to know what the conscious experience of a “truly unconscious” emotional state that does not enter reflective awareness might be like, but in arguing that the states are a “prereflective” form of “unknowing . . . consciousness,” they are presumably referring to something like Block’s unaccessed phenomenal consciousness.
Consciousness in the conventional sense (the sense in which we are aware of experiencing something) seems to depend on cortical processes. This is assumed by Block’s first-order theory as well as the other information-processing theories discussed above. The processes under discussion in these theories are part of the same general cortical information-processing system. The well-established role of the visual cortex in working memory, including attention, and other cognitive functions thus provide a framework for testing where in the cortical system conscious awareness emerges from information processing. Thus, the processes are grounded in well-established circuit interactions between the visual cortex and the prefrontal and parietal cortices, and the debate is fundamentally about where in that cortical processing system consciousness emerges.
Less clear is how subcortical circuits give rise to conscious states. Why does activity in body-sensing or command system circuits give rise to conscious states, but activity in adjacent areas that control breathing, heartbeat, or reflex movements to pain or loud noise or sudden visual stimuli does not? One could make a case that the subcortical body-sensing circuits in Damasio’s theory and subcortical emotion command circuits in Panksepp’s theory stand in a somewhat similar relationship to cognitive consciousness as the visual cortex does. That is, the subcortical areas create first-order phenomenal experiences and then, by way of connections from the subcortical areas to cortical areas, cognitive access to the subcortical processes could be possible. But that’s the easy part. The hard part in any first-order theory is explaining how the first-order state, independent of cognitive access, is consciously experienced on its own, something that has proven difficult in visual cortex and that is likely to be even harder to nail down in the brainstem.
Even if it could be shown in humans that some sort of primitive consciousness can be sustained by the brainstem, demonstrating that such states of consciousness exist in animals would face all the hurdles discussed so far. As we’ve seen, in animals hypothetical conscious states have to be tested by nonverbal responses, which leads to a formidable measurement problem: It is very difficult to distinguish whether nonverbal responses are based on conscious versus nonconscious processes without a verbal response as a contrast. The use of commentary keys and other clever experimental wizardry can generate evidence consistent with the idea of metacognition in animals, but even those conducting the studies acknowledge that a gap remains between establishing metacognition and proving animal consciousness."
(LeDoux, Joseph.
Anxious: Using the Brain to Understand and Treat Fear and Anxiety. New York: Viking, 2015. pp. 174-6)
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