Figure 3. Schematic illustrations of HNN’s underlying neocortical network model.

(A) Local Network Connectivity: GABAergic (GABAA/GABAB; lines) and glutamatergic (AMPA/NMDA; circles) synaptic connectivity between single-compartment inhibitory neurons (orange circles) and multi-compartment layer 2/3 and layer five pyramidal neurons (blue neurons). Excitatory to excitatory connections not shown, see Materials and methods. (B) Exogenous proximal drive representing lemniscal thalamic drive to cortex. User defined trains or bursts of action potentials (see tutorials described in text) are simulated and activate post-synaptic excitatory synapses on the basal and oblique dendrites of layer 2/3 and layer five pyramidal neurons as well as the somata of layer 2/3 and layer five interneurons. These excitatory synaptic inputs drive current flow up the dendrites towards supragranular layers (red arrows). (C) Exogenous distal drive representing cortical-cortical inputs or non-lemniscal thalamic drive that synapses directly into the supragranular layer. User defined trains of action potentials are simulated and activate post-synaptic excitatory synapses on the distal apical dendrites of layer 5 and layer 2/3 pyramidal neurons as well as the somata of layer 2/3 interneurons. These excitatory synaptic inputs push the current flow down towards the infragranular layers (green arrows). (D) The full network contains a scalable number of pyramidal neurons in layer 2/3 and layer 5 in a 3-to-1 ratio with inhibitory interneurons, activated by user defined layer specific proximal and distal drive (see Materials and methods for full details).