Identification of Specific Abnormal Brain Functional Activity and Connectivity in Cancer Pain Patients: A Preliminary Resting-State fMRI Study.

Objective: This study investigates the differences in brain functional activity and connectivity patterns between Cancer Pain (CP) patients and Healthy Controls (HCs) using resting-state functional magnetic resonance imaging (rs-fMRI) to identify potential neuroimaging biomarkers.

Methods: This study collected rs-fMRI data from 25 CP patients and 25 hCs, processed the functional MRI images, and calculated metrics such as amplitude of low-frequency fluctuation (ALFF), Regional Homogeneity (ReHo), and FC. Through statistical analysis, differences in brain functional activity and connectivity between the cancer pain group and the healthy control group were investigated, followed by machine learning classification.

Results: The results showed that compared to the normal group, reductions in the ALFF were primarily observed in the bilateral inferior temporal gyrus; ReHo increased in the right middle temporal gyrus and decreased in the left cerebellum Crus2. Using the statistically different brain areas as seed points to construct FC networks and performing statistical analysis, it was found that the regions with decreased FC connection strength between the cancer pain group and the normal group were mainly in the prefrontal cortex (PFC), the postcentral gyrus of the parietal lobe, and the cerebellum. Statistical results indicated that there was no significant correlation between pain scores (Numeric Rating Scale, NRS) and neuroimaging metrics. According to the machine learning classification, the FC features of the right precentral gyrus achieved higher diagnostic efficacy (AUC = 0.804) compared to ALFF and ReHo in distinguishing between CP patients and HCs.

Conclusion: Brain activity and FC in CP patients show abnormalities in regions such as the inferior temporal gyrus, middle temporal gyrus, prefrontal cortex, parietal lobe, and cerebellum. These areas may be interconnected through neural networks and jointly participate in functions related to pain perception, emotion regulation, cognitive processing, and motor control. However, the precise connections and mechanisms of action require further research.