Most of the information appears not to have been updated in years.
That's because most of what needed to be documented hasn't changed in decades. Many changes are expected in NEURON version 9, especially metadata features that will be particularly useful for code introspection; this will doubtless be accompanied by new documentation.
WRT BEFORE BREAKPOINT and AFTER SOLVE, these keywords are actually documented, and that documentation is in the most appropriate location: at the start of the file that uses them: xtra.mod, which implements the xtra mechanism that is used for extracellular stimulation and recording. That documentation, quoted here, seems fairly explicit:
Prior to NEURON 5.5, the SOLVE statement in the BREAKPOINT block
used METHOD cvode_t so that the adaptive integrators wouldn't miss
the stimulus. Otherwise, the BREAKPOINT block would have been called
_after_ the integration step, rather than from within cvodes/ida,
causing this mechanism to fail to deliver a stimulus current
when the adaptive integrator is used.
With NEURON 5.5 and later, this mechanism abandons the BREAKPOINT
block and uses the two new blocks BEFORE BREAKPOINT and
AFTER SOLVE, like this--
BEFORE BREAKPOINT { : before each cy' = f(y,t) setup
ex = is*rx*(1e6)
}
AFTER SOLVE { : after each solution step
er = (10)*rx*im*area
}
This ensures that the stimulus potential is computed prior to the
solution step, and that the recorded potential is computed after.
The reference to cy' = f(y,t) is a bit obscure because of its conciseness; the curious are referred to section
4.2.4.1 Implementational considerations in the NEURON Book, especially the discussion of Equations 4.29a et seq.. If you don't have the book, get this preprint
https://www.neuron.yale.edu/ftp/ted/boo ... xedref.pdf and look for the section with the header
Adaptive integration: fast or accurate, occasionally both
AFAIK these keywords appear only in xtra.mod and files derived from it (e.g. xrec.mod, which is used only for extracelluar recording). They certainly aren't useful for any of the NMODL descriptions of ligand- and/or voltage-gated channels, or ion accumulation mechanism (buffers, pumps, exchangers, smooth endoplasmic reticulum, mitochondria, Frankenhaeuser-Hodgkin space or other zones of restricted diffusion), or synaptic mechanisms with or without synaptic plasticity (hebbian or non-hebbian), or artificial spiking cells. Fairly extensive documentation with examples pertinent to most of these applications is in the enhanced preprint of
Hines, M.L. and Carnevale, N.T. Expanding NEURON's Repertoire of Mechanisms with NMODL. Neural Computation 12:995-1007, 2000
which is available as
https://neuron.yale.edu/neuron/static/p ... odl400.pdf
An introduction to using NMODL to implement of models of artificial spiking cells is presented in
Carnevale, NT and Hines, ML. 312.10 Efficient discrete event simulation of spiking neurons in NEURON.
Annual Meeting of the Society for Neuroscience, 2002, vol. 32.
which is available at
https://www.neuron.yale.edu/neuron/stat ... poster.pdf
Some additional information about event-driven simulation is presented in
Hines, ML and Carnevale, NT. Discrete event simulation in the NEURON simulation environment.
Neurocomputing 2004, 58-60:1117-1122. DOI 10.1016/j.neucom.2004.01.175