Which of the following statements about neural function and information processing is INCORRECT?
a) Extracellular chemicals other than neurotransmitters and neuromodulators can cause facilitation or inhibition of function in neurons.
b) The rate of action potential generation at a postsynaptic membrane is constant for each particular synapse.
c) If the axon hillock remains depolarized for an extended time, a new action potential will be generated as soon as the absolute refractory period of the previous one has ended.
d) When an EPSP or IPSP occurs at an axonal synapse, there can be presynaptic inhibition or presynaptic facilitation of neurotransmitter release from the synaptic knob.