Fig. 6.
The major variables involved in astrocyte-dependent information processing. Here, the input signal is same as in Fig. 3a and is omitted. Output f is feeding back into input a. a Increased bouton IP3 concentration in response to elevated extra-synaptic glutamate concentration (see f). b Increased IP3 concentration causes the IP3R channels to open and leads to a transient enhancement in bouton [Ca2 + ], due to the influx of Ca2 + from IP3R (see Ca2 + concentration after 20 seconds). c Accumulated bouton [Ca2 + ] leads to increased transients of glutamate concentration in the synaptic cleft. d Transients of glutamate concentration set off the production of astrocytic IP3 concentration through a mGluR dependent pathway. e Elevated astrocytic IP3 concentration causes the IP3R channels to open and initiates astrocytic Ca2 + oscillations. f Astrocytic Ca2 + oscillations instigate the process of SLMV fusion, which is followed by a raised extra-synaptic glutamate concentration. This elevated extra-synaptic glutamate concentration forms the basis of bouton IP3 production shown in a