Figure 1.

Physiological activity in cortical network with [K⁺]_o dynamics. A, Color-coded activity map of 200 PYs (cool and hot colors indicate hyperpolarization and depolarization, respectively). B, Color-coded [K⁺]_o map corresponding to activity in A. C, Firing rate histograms for pyramidal cells and inhibitory interneurons. D, Top, Overlaid membrane voltage traces of three neighboring pyramidal cells (PY 1, PY2, and PY 3 in blue, black, and red, respectively). Bottom, [K⁺]_o in extracellular compartment surrounding PY 2. Minor deflections stem from action potentials in neighboring cells PY 1 and PY 3 (diffusion), major deflection from action potentials in PY 2.