Figure 3. Different physiological states, two different roles of caspase-3 in the brain.

Graph showing variables related with the activation of caspase-3 that determine its function in neuronal circuitries: signal intensity, duration of activation and proximity to the synapse. This model suggests that the function of caspase-3 depends on the context in which it is activated. When signals perceived by neurons are transduced and integrated, caspase-3 activity is modified leading to two possible outcomes (color dots): the enrollment of caspase-3 in synaptic plasticity processes, or its participation in cell death pathways. The model predicts the existence of a threshold of caspase-3 activity that determines its role during any neuronal state; the threshold is determined by the strength and quality of all the variables involved in caspase-3 activation.