The Plastic Glial-Synaptic Dynamics within the Neuropil: A Self-Organizing System Composed of Polyelectrolytes in Phase Transition

Figure 3

Schema of circling wave experiment with a potassium sensitive electrode inserted in the inner plexiform layer. A circular cut created an inner circular area separating the outer ring and the inner circle. The gap is filled with the perfusion solution. A wave is elicited in the outer ring and one wavefront is killed by aspersion with a high MgCl₂ (4 mEq/L) solution. The perfusion rate is transiently increased such that the remaining wavefront is kept propagating. The electrode was positioned within 0.5 mm of the border of the circular cut. The potassium activity and the extracellular local potential are recorded simultaneously. At the side of each potassium activity wave and extracellular potential drop, the peak values are shown in mEq/L and mV. The values shown are typical of this type of experiment, as well as the shape of the potassium and potential wave concomitants. “Spontaneous” waves appeared at the inner circle and potassium activity increased in the solution gap and at the inner plexiform layer of the outer ring. Two potassium activity transients are shown (arrows). Note that both do not influence local extracellular potential, although the potassium activity waves were affected (expected in system with hysteresis). Note also that the relation between potential and potassium peaks is not linear (modified from [74]).