Distinct Patterns of Directed Brain Connectivity in Focused Attention, Open Monitoring, and Loving Kindness Meditation: An Electroencephalographic Granger Causality Study with Long-term Meditators.

The present study applied spectral Granger causality (GC) analysis to EEG recordings obtained during focused attention meditation (FAM), open monitoring meditation (OMM), and loving kindness meditation (LKM) in highly experienced meditators. The aim of the investigation was to characterize distinct connectivity signatures associated with each meditation style by examining the strength, frequency, and direction of interregional interactions. These differences were expected to specify the neural connectivity profiles of the cognitive and affective state of each meditative practice. Multivariate GC was computed from high-resolution EEG signals recorded from long-term meditators (n = 22) in four conditions: rest, FAM, OMM, and LKM. GC was analyzed in the frequency domain for key electrode clusters (anterior and posterior) in the two hemispheres to compare frequency-specific directed connectivity between rest and each meditation type. Main results demonstrated that each meditation state produced highly specific alterations in directed influences relative to rest. In FAM, there was significant reduction in posterior-to-anterior GC in the alpha and beta bands as well as decreased multispectral interhemispheric frontal GC implying attenuated bottom-up sensory and associative inputs. In OMM, multispectral GC was significantly increased from the left hemisphere to the right posterior cluster implying expanded awareness in the right posterior regions through enhanced top-down modulation by the left hemisphere. The distinctive features of LKM profile were the interhemispheric symmetry, the posterior-anterior bidirectionality, and the specific beta-band engagement, implying a coactivation of systems that support an emotionally balanced stance, equanimity, and prosocial attitude. These novel findings demonstrate that the direction and frequency specificity of information flows provide complementary insights into neural processes underlying distinct meditative states.