A Research Of The Construction Of Primary Perceptual Circuits Related To Pain And The Relationship Between Circuits And Emotion

Pain has been regarded as the fifth vital sign.Normal pain is beneficial to the body’s warning of injury and monitoring of health,while abnormal pain will bring us physical suffering and life pressure.In recent years,there have been many researches on the neural mechanism of pain,but the processing of pain signals in the related circuits of the brain is still unclear.In addition,studies have shown that different individuals perceive pain differently.Up to now,there is still a lack of scientific explanation for the individual differences in somatosensory sensation and tolerance such as pain in academic circles.Therefore,research on pain can help us decode the processing of perception in the brain and explore the neuroimaging mechanisms of individual differences in pain perception.In addition,studies have shown that pain-related brain networks are also involved in emotional processing.The two cognitive processes of pain and emotion share certain circuits in the brain,but the sharing mechanism is still unclear.The results of research on the neural mechanisms of pain may be transferable to the cognition of the neural mechanisms related to emotion.Therefore,this study used Magnetic Resonance Imaging(MRI)data to construct pain-related circuits,extract its brain imaging indicators,and establish the correlation between these indicators and Anxiety Scale.This may help us to explore the mechanism of anxiety state production,and then achieve decoding specific anxiety states based on brain images,which is expected to provide information of key target networks for anxiety state intervention.In study one,we would preliminarily construct the primary perception circuit related to pain,and explored the relationship between this circuit and anxiety.Structural MRI(s MRI),functional MRI(f MRI)and diffusion MRI(d MRI)data were collected from 35 male subjects recruited at the University of Electronic Science and Technology of China.Before scanning,the anxiety scale was evaluated and the tolerance time to cold pain stimulation was recorded.According to the different tolerance time of the subjects in the ice water at about 1℃,the subjects were divided into the pain-sensitive group and the pain-tolerant group.Then,based on the diffusion coefficient map of the d MRI data preprocessing results,the white matter skeleton analysis was performed on the two groups of subjects.The results showed that there were differences between the two groups of subjects in the part of uncinate fasciculus,inferior longitudinal fasciculus,inferior fronto-occipital fasciculus,superior longitudinal fasciculus,corticospinal tract,cingulum,anterior thalamic radiation,and the corpus callosum radiation.Therefore,we believed that pain sensitivity might be related to the transmission of pain signals in the brain,and based on previous studies we believed that the thalamus is a key region of pain signal transmission.Therefore,we constructed the core pain-related signaling pathway,the thalamocortical loop,and examined its white matter connectivity by fusing s MRI and d MRI data.The results showed that between the two groups there was a significant difference in the mean connection strength between the left brain’s paracentral sulcus and gyrus,subcallosal gyrus,inferior circular insula sulcus,inferior precentral sulcus and left thalamus.and between the right brain’s middle occipital gyrus,lingual gyrus nearby occipital and middle temporal,rectus gyrus,middle temporal gyrus,anterior lateral fissure of vertical,middle occipital sulcus and lunatus and right thalamus.Subsequently,We then correlated the average connection strength of these 10 different brain regions with the anxiety scale calculations,and found a significant correlation between the mean connection strength of the left thalamus and left paracentral sulcus gyrus and the trait anxiety scale scores.The results suggested that pain sensitivity was associated with connectivity of the thalamocortical circuit,and that parts of this circuit were also involved in anxiety emotion processing.In study two,we found that pain sensitivity was not only related to white matter connectivity,but might also be involved in more complex,multiregional coupling and regulation based on previous studies.Therefore,we used the subjects of study one to calculate probabilistic tracking-weighted functional connectivity(FC)by fusing d MRI and f MRI data to investigate the regulatory effect of basal ganglia nuclei on thalamocortical circuits.The results showed that there were significant differences between the two groups in parts of the frontal and parietal lobes of the left brain and in parts of the frontal and angular gyrus of the right brain.In addition,we also correlated the FC mean value of these different regions with the anxiety scale.The results showed that there was a significant correlation between them and the trait anxiety scale.These results suggested that the basal ganglia was involved in the regulation of pain-related brain circuits,and that these brain region was also involved in anxiety emotion processing.In conclusion,this study used probabilistic tracking and functional connection methods,and found that the connection between the thalamus and the cortex maight be a key circuit for pain tolerance.We called this circuit primary perceptual circuits related to pain,and revealed the composition of this circuit and its relationship with basal ganglia.The correlation between the mean strength of connections between the cortical and thalamus in this circuit and the anxiety scale score suggested that part of this circuit is involved in anxiety emotion processing and deepens our understanding of the primary perceptual circuits related to pain and their relationship to anxiety.