Macro scale modelling of cortical spreading depression and the role of astrocytic gap junctions

Under pathological conditions (determined by model parameters) and with extracellular electrodiffusion the model is able to simulate a propagating wave of high extracellular K+ travelling at 6.7 mm/min as can occur in CSD. This wave travels outward from the neuronally stimulated area and is followed by a wave of vasoconstriction (with corresponding decreased blood flow) then slight vasodilation in agreement with multiple experimental results. The vasoconstrictive wave peaks after the K+ wave due to the delayed vascular response. Increasing the density of astrocytic gap junctions reduces the duration and amplitude of the vasoconstrictive wave and for high enough density the vasoconstrictive behaviour outside the stimulated area is eliminated. Gap junctions also reduce the area that is initially affected by vasoconstriction. This in silico model provides a complex and experimentally validated test bed for a variety of neurological phenomena.