Cerebellar Alteration in Resting-State Functional Connectivity Among Kratom (Mitragyna speciosa) Users: Insights from Functional MRI.

Due to the psychotropic properties of kratom (Mitragyna speciosa), further studies are needed to measure its neurobiological impacts. This exploratory study employed resting-state functional magnetic resonance imaging (rs-fMRI) to examine alterations in brain activity and functional connectivity (FC) among kratom users. A total of 43 respondents were recruited (22 regular kratom users and 21 healthy controls). RS-fMRI data were acquired using a 1.5T GE Signa HDxt scanner. Preprocessing and analysis were performed with Statistical Parametric Mapping 12 (SPM 12) and CONN toolbox. Group differences in the low-frequency fluctuations (LFFs) and FC were examined. Kratom users exhibited reduced LFF in brain regions critical to the default mode network (DMN), cognitive control, and self-referential processing, including the precuneus, superior frontal gyrus, and cerebellar and cingulate cortices. They also showed increased FC between salience and cerebellar networks, specifically in the posterior cerebellum, and left rostral prefrontal cortex (RPFC). Chronic kratom consumption may alter brain activity, especially in areas linked to the DMN, cognition, and reward processing. Enhanced FC between salience and cerebellar networks may reflect compensatory mechanisms or adaptations to kratom's effects. Further research is crucial to elucidate the underlying mechanisms and potential implications for cognitive function and addictive behaviors.