The Unexplored Territory of Neural Models: Potential Guides for Exploring the Function of Metabotropic Neuromodulation

•Neural network models fail to incorporate many dimensions of physiological function regulated by metabotropic receptors.•Enumeration of the dimensions of metabotropic regulation of physiological function reveals unexplored areas of model space.•Not enough models address metabotropic regulation of adaptation, persistent and rebound spiking, and presynaptic inhibition.•Underexplored properties include metabotropic regulation of nonlinear dendritic interactions and synaptic plasticity.