Beyond the Mean Field
Most TVB-O models put a single averaged unit at each region. That is the right level for whole-brain dynamics, and the wrong one as soon as the question turns on individual spikes, a specific ion channel, or what a detailed patch does inside an otherwise coarse brain.
Two escapes exist, and they answer different questions.
Reference a detailed cell model. Single neurons, ion channels and synapses are available by IRI: set iri: neuroml:<TypeName> on a dynamics and TVB-O pulls the equations from the NeuroML2 library rather than making you transcribe them. See IRI vs. inline YAML and the example gallery.
Run two scales together. Multi-scale modelling covers what it means to couple a detailed patch to a whole-brain model, which pairings TVB-O supports today, and an honest status for each. Not every combination works yet, and that page says which.
The macro network a detailed patch attaches to is specified the ordinary way, in Networks & connectomes.
Reference
subnetwork · source_network · target_network · NeuroML component mapping.