Figure 4
From: A biophysical model explains the spontaneous bursting behavior in the developing retina
Biophysical mechanism for bursting in immature SACs. (1) Fast spiking occurs due to the competition between voltage gated Ca2+ (excitatory current) and K+ channels (inhibitory current). (2) Calcium load increases during the rapid firing phase while the voltage is in a high voltage state. This leads to a slow increase of sAHP. When sAHP is large enough there is a sharp decay of the voltage (bifurcation) and the hyperpolarisation phase of the cell starts. As voltage is low, the calcium load starts to slowly decrease. (3) During the slow offloading calcium stage we observe a refractory phase. The decrease of calcium concentration induces a slow decay of the sAHP. When calcium is small enough rapid firing starts again via a new bifurcation.
