Hard Problem of Consciousness, Affective and Subcortical theories

Hard Problem of Consciousness : Affective/Subcortical theories

This is the last post in this series on FEP and consciousness focusing on the “hard problem” of consciousness that centers on the question of how and why neurophysiological processes in the brain give rise to subjective experiences, such as the vivid perception of colors or the emotional impact of music. Emerging theories propose an integrated approach, viewing consciousness as fundamentally rooted in affective and subcortical processes. This perspective emphasizes the interconnectedness of mental and physical phenomena, with consciousness arising from the dynamic interplay between brainstem activities, emotional states, and cognitive functions. By exploring the role of affect in guiding adaptive behavior and learning, these theories offer a better understanding of consciousness that bridges the gap between subjective experiences and their physiological processes.

As we discussed earlier, consciousness is one of the most difficult puzzles in philosophy and neuroscience. The underlying physical processes that give rise to consciousness and the neurophysiological activities that produce the experience of consciousness remain unclear. Attempts to address this question often conceptualize the brain as a producer or cause of consciousness, but such formulations may further complicate rather than clarify the nature of the problem. The relationship between the brain and the mind is not simplistic and causal, therefore presenting consciousness to a byproduct of physiological processes fails to capture its essence. Instead, viewing the body and mind as two sides of the same coin i.e. the same underlying reality challenges us to reconsider our ontological assumptions. If both body and mind are manifestations of a deeper (or transcendant) reality, what underlies their existence? In other words, similar to the relationship between thunder and lightning, what would be the metaphysical equivalent of “electricity”? Clarifying the ontological status of terms like “physical basis” and “neurobiological processes” requires a nuanced understanding of their underlying meaning. Rather than viewing physiological phenomena as distinct from their mental counterparts, we should recognize their interconnectedness. Memory, for instance, is not a tangible entity but a functional process that manifests both psychologically and physiologically. By abstracting underlying functional laws from observable phenomena, we can bridge the apparent gap between conscious experience and its neural correlates.

The hard problem of consciousness refers to the difficulty in explaining why and how we have subjective, first-person conscious experiences from the physical processes occurring in our brains. It is difficult to explain why these physical processes should also give rise to the felt sensations and subjective experiences that each of us intimately knows - the red color you perceive when looking at an apple, the painful feeling of being burned, or the rich quality of hearing a trumpet play. This is the “hard” part of the problem. Subjective conscious experiences seem fundamentally different from the objective, physical processes described by science. There appears to be an “explanatory gap” between the two domains. Even if we fully understood the brain’s physical mechanisms, there would still be a further question of why these processes are accompanied by conscious experience at all. The existence of subjective consciousness seems irreducible to physical facts alone. Proposed solutions involve new fundamental laws connecting physical processes to consciousness, or more radical ideas that consciousness is a fundamental feature of the universe itself. But there is no agreed upon solution yet.

Free Energy Principle can be applied to the hard problem of consciousness, where the affect is presented as consciousness’ elemental form and its physiological mechanism located in the upper brainstem. Consciousness emerges not merely as a byproduct of neurophysiological activities but as a profound interplay between different levels of a hierarchical structure, with memory, as both a psychological and physiological process, highlighting the interconnectedness between mental and physical phenomena. Consciousness, as a mechanism for monitoring internal states in relation to external forces, is inherently tied to affective processes that guide adaptive behavior. Affective states form the basis of consciousness, with emotional learning supplementing innate predictions and shaping conscious experiences. This integration of affective and cognitive aspects of consciousness underscores the fundamental role of emotions in guiding adaptive behavior and learning, providing a nuanced understanding of the subjective nature of consciousness.

As we mentioned before in this series on FEP, Homeostasis is crucial for the existence and persistence of self-organizing systems like living organisms. Self-organizing systems resist entropy by occupying preferred states, thus maintaining their integrity over time. Three conditions must be met for a system to resist entropy: the presence of a boundary separating internal and external states, a mechanism to register dissipative external forces (sensory states), and a mechanism to counteract these forces (action). The concept of a Markov blanket, which establishes boundary conditions and separates the system from the external environment, is central to this explanation. The sensory and active capacities of the blanket allow the system to vicariously infer external states and act upon them based on sensory impressions. This necessitates the incorporation of a model of the world, which serves as the basis for perception and action. Through ongoing processes of hypothesis testing, the system updates its model, optimizing its predictions and minimizing free energy. In the context of nervous systems, all other bodily systems are considered external, with the nervous system performing meta-homeostatic functions on their behalf. Nervous systems co-evolved with other bodily systems to orchestrate multiple homeostatic demands, thus regulating the organism as a whole. The mechanisms this meta-homeostasis involve both physiological and psychological processes, with abstract concepts like inference, belief, and prediction. This abstract ontology allows for a unified explanation of homeostasis and its role in the function of consciousness, bridging the gap between physiological and psychological phenomena.

The question of why we feel is central in neuroscience. At its core, feeling is understood as the registration of bodily states within a biological scale of values, where pleasurable feelings signal improving chances of survival and reproductive success, while unpleasurable feelings signify deteriorating conditions. Feelings are not localized in the cortex but originate in the brainstem and limbic system, to cover autonomic and intrinsic brain states. As mentioned above the shift in focus to the brainstem highlights the primal nature of consciousness, serving as a mechanism for organisms to monitor and regulate deviations from homeostatic equilibrium in unpredictable contexts. Feelings, in this context, enables organisms to prioritize actions and make adaptive choices based on the assessment of relative value attached to different alternatives. Pleasure accompanies a return to homeostasis, while unpleasure signifies deviation from it, prompting the organism to take corrective action. Emotional valence, arising from deviations in homeostatic settling points, serve as signals guiding behavior and learning. By prioritizing needs and opportunities, consciousness emerges as a biological imperative, facilitating survival and adaptation in novel environments. Ultimately, consciousness is quintessentially affective, rooted in the primal imperative of maintaining biological integrity and adapting to the challenges of life. It is through feeling that organisms navigate the uncertainties of existence, ensuring their continued survival and success in the ever-changing landscape of the world.

Contrary to the view, which puts the cortex as the “seat” of consciousness, recent evidence discussed here suggests that consciousness might come from subcortical regions. The cortex, rather than generating consciousness, may serve as a facilitator or stabilizer of affective arousal, transforming it into conscious cognition. This reinterpretation aligns with the plasticity of the cortex and the hierarchical dependency between brainstem arousal and cortical consciousness. Studies of emotional and cognitive reactions in such beings point to the existence of a basic form of consciousness, rooted in subcortical structures. In this view, consciousness emerges as fundamentally affective, rooted in the arousal processes of the upper brainstem. This reformulation challenges traditional paradigms and prompts a reevaluation of the functional mechanisms underlying consciousness.

Solms (2013, 2014) and further Friston (2018) mentioned that the The emergence of consciousness is rooted in the dynamics of free energy minimization and uncertainty in subcortical regions of the brain. Initially proposed as the basic function of homeostasis, free energy minimization is performed by brainstem nuclei centrally implicated in the generation of conscious experience. In this framework, fundamental properties of mind, such as selfhood and intentionality, arise from the dynamics of FE through Markov blankets, which separates the system from the external environment, with the imperative for self-organizing systems to monitor their internal states in relation to external forces leads to the emergence of subjective observational perspectives and active forms of subjectivity. In other words, Consciousness emerges as self-organizing systems monitor their internal states in relation to potentially annihilatory forces, leading to inherently value-laden processes that is predicated upon the imperative of survival. While proto-mental dynamics involve the computation of subjective values at the level of autonomic homeostasis, the transition to conscious, qualitative mental states revolves around increasing complexity. Qualitative fluctuations in affect arise from continuous comparisons between predicted and actual sensory states, signaling changes in uncertainty and expected consequences of action. This process of precision optimization is inherently affective, with affect playing a central role in engaging with the outside world and determining subjective engagement.

This is the last post in this series for now, where we discussed that the, emergence of conscious self-states is fundamentally rooted in affective states, serving as a mechanism guiding self-organizing systems through situations that rise the variational free energy. While instinctual behaviors provide innate survival tools, they cannot address the complexities of actual environmental niches. Consequently, innate predictions are supplemented by learning from experience, leading to emotional responses with emotional learning aiming to improve predictions. Non-declarative memories, associated with subcortical systems, involve simpler cause-and-effect links and cannot be retrieved as mental images. Declarative memories, processed in cortical systems bring back long-term memory (LTM) traces to conscious working memory for updating. Conscious cognitive processes, involving cortical consciousness, delay motor responses to affective demands, enabling through thinking (i.e. weighting the posteriors and their distance from the priors). Along these lines, the essential function of cortex is stabilizing non-declarative executive processes, elevating them to a higher cognitive level, i.e., the bound state, referring to working memory.

References

#Free Energy Principle    #Affect    #Consciousness   

December 2024