  At the inception of human brain mapping, two principles of functional anatomy
underwrote most conceptions - and analyses - of distributed brain responses:
namely functional segregation and integration. There are currently two main
approaches to characterising functional integration. The first is a mechanistic
modelling of connectomics in terms of directed effective connectivity that
mediates neuronal message passing and dynamics on neuronal circuits. The second
phenomenological approach usually characterises undirected functional
connectivity (i.e., measurable correlations), in terms of intrinsic brain
networks, self-organised criticality, dynamical instability, etc. This paper
describes a treatment of effective connectivity that speaks to the emergence of
intrinsic brain networks and critical dynamics. It is predicated on the notion
of Markov blankets that play a fundamental role in the self-organisation of far
from equilibrium systems. Using the apparatus of the renormalisation group, we
show that much of the phenomenology found in network neuroscience is an
emergent property of a particular partition of neuronal states, over
progressively larger scales. As such, it offers a way of linking dynamics on
directed graphs to the phenomenology of intrinsic brain networks.
