Toward the unknown: consciousness and pain

Abstract

Studies of consciousness are hindered by the complexity of the brain, but it is possible to study the consciousness of a sensation, namely pain. Three systems are necessary to experience pain: the somatosensory system conveys information about an injury to the thalamus where an awareness of the injury but not the painfulness emerges. The thalamus distributes the information to the affective system, which modulates the intensity of the pain, and to the cognitive system that imparts attention to the pain. Imaging of patients in pain and those experiencing placebo and hypnosis-induced analgesia shows that two essential cortical circuits for pain and attention are located within the anterior cingulate cortex. The circuits are activated when a high-frequency input results in the development of a long-term potentiation (LTP) at synapses on the apical dendrites of pyramidal neurons. The LTP acts via α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors, and an anterior cingulate cortex–specific type-1 adenylate cyclase is necessary for both the LTP and the pain. The apical dendrites form an extensive network such that the input from serious injuries results in the emergence of a local field potential. Using mouse models, I propose experiments designed to test the hypothesis that the local field potential is necessary and sufficient for the consciousness of pain.

Cortical synaptic basis of consciousness

“…It has to be pointed out that there are different aspects of consciousness including awareness of the environment by sensory stimuli, and volition, the voluntary control of thoughts and feelings (Albright et al , 2000). In understanding synaptic and molecular mechanisms of consciousness, it is highly possible that the very first component of consciousness can be tackled at the present time and consciousness of different forms of pain is a key indicator for consciousness (Ambron, 2023).…”

“…Acute pain, which is a short-lasting stimulus, is known to increase the level of consciousness. It has been proposed that sensory pain-related consciousness may provide an excellent model for studying consciousness itself (Tiengo, 2003;Gu et al , 2013;Ambron, 2023). In patients with DOC, it has been reported that there is a strong correlation between the responsiveness to nociceptive stimuli and the level of consciousness (Thibaut et al , 2018).…”

Cortical synaptic basis of consciousness

“…It has to be pointed out that there are different aspects of consciousness including awareness of the environment by sensory stimuli, and volition, the voluntary control of thoughts and feelings (Albright et al, 2000). To understand synaptic and molecular mechanisms of consciousness, it is highly possible that the very first component of consciousness can be tackled at the present time and consciousness of different forms of pain is a key indicator for consciousness (Ambron, 2023).…”

“…Acute pain, which is a short‐lasting stimulus, is known to increase the level of consciousness. It has been proposed that sensory pain‐related consciousness may provide an excellent model for studying consciousness itself (Ambron, 2023; Gu et al, 2013; Tiengo, 2003). In patients with DOC, it has been reported that there is a strong correlation between the responsiveness to nociceptive stimuli and the level of consciousness (Thibaut et al, 2018).…”

Altered cognitive control network mediates the association between long-term pain and anxiety symptoms in primary dysmenorrhea

“…The management [9,10] However, many chronic pain studies have shown that dysfunction of cognitive control may have significant implications for the onset and maintenance of chronic pain [11,12]. The interaction between somatosensory, emotional, and cognitive systems produces the experience of pain [13]. Studies have also shown that cognitive or emotional factors are strongly correlated with resting-state fMRI data, suggesting that the brain retains some activity for these pain-related factors even at rest [14].…”