The Consciousness of Pain: A Thalamocortical Perspective

Abstract

Deep, dreamless sleep is considered the only “normal” state under which consciousness is lost. The main reason for the voluntary, external induction of an unconscious state, via general anesthesia, is to silence the brain circuitry of nociception. In this article, I describe the perception of pain as a neural and behavioral correlate of consciousness. I briefly mention the brain areas and parameters that are connected to the presence of consciousness, mainly by virtue of their absence under deep anesthesia, and parallel those to brain areas responsible for the perception of pain. Activity in certain parts of the cortex and thalamus, and the interaction between them, will be the main focus of discussion as they represent a common ground that connects our general conscious state and our ability to sense the environment around us, including the painful stimuli. A plethora of correlative and causal evidence has been described thus far to explain the brain’s involvement in consciousness and nociception. Despite the great advancement in our current knowledge, the manifestation and true nature of the perception of pain, or any conscious experience, are far from being fully understood.

Brain structural and functional abnormalities in patients with tension‐type headache: A systematic review of magnetic resonance imaging studies

“…Additionally, the left caudate and left thalamus showed reduced spontaneous activity (Li et al., 2021), indicating decreased intrinsic neural fluctuations. As the thalamus recruits sensory information from spinal, supraspinal, and cortical regions, including nociceptive pathways, it is pivotal for awareness, cognition, and pain modulation (Ab Aziz & Ahmad, 2006; Sgourdou, 2022). While thalamic involvement in the sensory and affective dimensions of pain, along with its structural and functional changes in migraines and TTH (Ab Aziz & Ahmad, 2006; Valenzuela‐Fuenzalida et al., 2021; Yang et al., 2022; Younis et al., 2019), supports its potential contributions to TTH pathophysiology, data remain limited.…”

Meditation as an Adjunct to the Management of Acute Pain

“…Consciousness remains a complex concept due to its multidimensionality and the uniqueness of each human experience, which is shaped by sensory, affective, and cognitive aspects. Simply defined, consciousness is a cognitive state in which one is aware of the individual experience and the surrounding environment [ 13 , 14 ]. Consciousness is dictated by the presence of wakefulness (level of consciousness) and awareness (context of consciousness) [ 14 ].…”

“…Simply defined, consciousness is a cognitive state in which one is aware of the individual experience and the surrounding environment [ 13 , 14 ]. Consciousness is dictated by the presence of wakefulness (level of consciousness) and awareness (context of consciousness) [ 14 ]. Additionally, neurobiological research divides the states of consciousness into two classes: global and local states of consciousness [ 15 ].…”

“…The International Association for the Study of Pain (IASP) defines pain as “an unpleasant sensory and emotional experience associated with, or resembling that association with, actual or potential tissue damage” [ 16 ]. Although the processing of nociception is largely unconscious, the perception of pain requires a state of consciousness (wakefulness and awareness) that is influenced by psychological and cognitive factors [ 13 , 14 ]. Traditional Buddhist texts have long suggested that pain perception is the result of both sensory and affective factors, and that trained meditators experience pain in a different way than untrained individuals.…”