Neurotransmission: Now, Soon, L.A.T.E.R., or Never?
Lobsters, Axons, Telephones, and Extracellular Recordings – A look at how neuronal signals can be transmitted differently under certain pharmacological conditions.
Neuronal signals are normally transmitted from cell bodies, or somas, to terminals via extensions called axons. At these terminals, connections called synapses are made with other neurons whereby the signals are released via the aide of chemical messengers called neurotransmitters. Many still believe that axons are reliable conductors of these signals.
However, with several years’ worth of experiments, scientists have questioned the fidelity of axonal conduction. They’ve realized that axons do not work like telephones. While telephones and axons may both have buttons – at the terminals in axons – only telephones faithfully conduct signals. And only telephones ring aloud and send messages to voicemail…
In any case, neuronal signals, unlike telephone signals, can change along their paths. Moreover, the pre-synaptic neuron may communicate a different message from the one originally sent from the soma to the synapse with the post-synaptic cell. Researchers at the lab I’ve been working at this summer, the Whitney Laboratory for Marine Bioscience, have focused on the role of neuromodulation in signal transmission along axons, particularly by the well-known neurotransmitter – dopamine. More
Neither free nor completely determined
Free will is a hackneyed topic. Science seems to be telling us that free will doesn’t exist because behavior is governed by the brain and the brain operates on physical rules of cause and effect. There is no such thing as uncaused cause, which free will requires. For some people this is an unbearable notion; these folks hang on to their perceived volition as evidence that they are in fact free to do as they choose, without being constrained by their biology. Others swallow what science has espoused long ago; of these folks, some tend to be pessimistic, thinking that their lack of free will means that everything is pointless and that the best thing they can do for themselves is to blur the line between their behind and a comfortable couch, until scientists discover the new species Homo sofus. More