Markov blankets in the brain

•We leverage the idea of ‘Markov blanket’ as a statistical boundary to provide an analysis of partitions in neuronal systems.•We show this partition is applicable to multiple scales, from single neurons, brain regions, and brain-wide networks.•Based on the canonical micro-circuitry, our treatment has practical applications for effective connectivity.•Our proposed partition highlights the limitations of ‘modular’ proposals considering a single level of description.