Middle out

See the diagram below from Nobel, D. (2008). The Music of Life. Oxford UP. It reminds me of what I wrote in this paper:

"A recent neuroimaging study (Smith et al., 2019) on brain connectome hierarchical complexity (HC) seems to support my notion that, like basic categories in cognitive science, HC arises from the middle out as 'bridges' rather than bottom-up or top-down. E.g. 

'Dividing the connectomes into four tiers based on degree magnitudes indicates that the most complex nodes are neither those with the highest nor lowest degrees but are instead found in the middle tiers. […] The most complex tier (Tier 3) involves regions believed to bridge high-order cognitive (Tier 1) and low-order sensorimotor processing (Tier 2). The results show that hub nodes (Tier 1(t)) and peripheral nodes (Tier 4(b)) are contributing less to the greater complexity exhibited in the human brain connectome than middle tiers. In fact, this is particularly true of hub nodes.' 

Also see Nobel's work The Music of Life Sourcebook:

"Note that the terms ‘bottom’, ‘up’, ‘middle’ and ‘out’ are conveying the sense of a hierarchy between levels of organization in biological systems that tends to ignore interactions that take place between levels in all directions. So very much as ‘bottom-up’ and ‘top-down’ approaches are arguably complementary, we should consider ‘out-in’ as well as ‘middle-out’ approaches in our attempts to integrate upward and downward causation chains" (8).