<Tr> <Td> Dendrite Soma Axon Nucleus Node of Ranvier Axon terminal Schwann cell Myelin sheath </Td> </Tr> <P> Dr. Wade Regehr, a Professor of Neurobiology at Harvard Medical School's Department of Neurobiology, developed a method to physiologically see the synaptic activity that occurs in the brain . A dye alters the fluorescence properties when attached to calcium . Using fluorescence - microscopy techniques calcium levels are detected, and therefore the influx of calcium in the presynaptic neuron . Regehr's laboratory specializes in pre-synaptic calcium dynamics which occurs at the axon terminals . Regehr studies the implication of calcium Ca as it affects synaptic strength . By studying the physiological process and mechanisms, a further understanding is made of neurological disorders such as epilepsy, schizophrenia and major depressive disorder, as well as memory and learning . </P>

Which of the following would not be found at the axon terminal