Don't think this is A???? Any idea what it is? How yguld an increase in external Ca2+ concentration affect synaptic depression? a. It would increase the rate of neurotransmitter release and delay depression. b. It would decrease the rate of neurotransmitter release and induce depression. c. It would increase the rate of depression. d. It would decrease the rate of depression. e. It would have no effect on depression..