Adaptation-induced suppression and facilitation: Effect of intra- and extracellular ionic disturbances
Adaptation to drifting-oriented gratings has been shown to cause orientation plasticity. To study adaptation induced responses we have developed a V1 population model having isotropic intracortical synaptic connections, incorporating sub-cellular and intrinsic membrane mechanisms. The model captures the finer details of recently reported experimental results on orientation plasticity and shows that pinwheel centers are foci of orientation plasticity. The model captures the tilt aftereffect and further explains how orthogonal adaptation can lead to sharpening of orientation tuning curves. We report here for the first time that adaptation not only causes response suppression but can simultaneously increase the excitability of the local neural tissue due to accumulated extracellular ionic disturbances. The increased excitability can lead to response facilitation for cells having the least intracellular ionic disturbances.
adaptation extracellular orientation plasticity calcium mitochondria