Right Hemispheric Neuronal Dysfunction in Cancer Pain: A Resting-State fMRI Exploratory Study

This exploratory study investigated the neurobiological mechanisms of cancer pain by examining functional brain alterations using resting-state functional magnetic resonance imaging (fMRI), aiming to characterize neural network changes and identify potential neuroimaging biomarkers.

A cross-sectional study was conducted from October 2021 to October 2022, involving 20 cancer pain patients and 20 age-, sex-, and education-matched healthy controls. Participants underwent comprehensive clinical assessments and 3.0T resting-state fMRI scanning. Inclusion criteria were patients aged ≥18 years with pathologically confirmed malignant neoplasms experiencing moderate to severe pain (NRS ≥ 4). Functional connectivity and low-frequency amplitude analyses were performed using the right nucleus accumbens as a seed region.

Significant neuroplastic changes were observed in cancer pain patients, primarily in the right hemisphere. Low-frequency amplitude analysis revealed reduced spontaneous neural activity in critical brain regions, including the right medial prefrontal cortex (T = -4.36), right superior/middle frontal gyrus (T = -5.21), and right precuneus (T = -4.15). Functional connectivity analysis showed substantially decreased connectivity between the right nucleus accumbens and bilateral medial prefrontal cortex (T = -4.86), left temporal pole (T = -5.62), and right superior temporal gyrus (T = -5.05).

The study provides preliminary evidence of right hemispheric neuronal dysfunction in cancer pain, highlighting altered functional connectivity in emotion regulation and pain processing neural circuits. These findings offer insights into the neurobiological mechanisms of cancer pain and potential objective assessment approaches.