I heard in a few places that a real neuron is nothing like a threshold unit, but more like a complete miniature computer. None of those places expanded on that, though. Could you?
I am not sure that I understand the exact difference between a threshold unit and a miniature computer that you want to shine a light on. Below are some aspects that may be of use to you:
The whole surface of a neuron is not at the same potential (relative to the firing potential). Synapses are many (can be thousands), along branching dendrites, of different types and strengths so that the patterns of input that will cause firing from the dendrite end of the neuron are varied and a large number. This architecture is plastic with synapses being strengthened and weakened by use and by events far away from the neuron. At the axon root synapses are fewer and their effect more individual. If the neuron fires it delivers its signal to many synapses on many other neurons. Again this is plastic.
The potential of the neuron surface is affected by many other things besides other neurons through the synapses. It is affected by electrical and magnetic fields generated by the whole brain (the famous waves etc.). It is affected by the chemical environment such as the concentration of calcium ions. These factors are very changeable depending on the activity of the whole brain, hormone levels, general metabolism etc.
It is fairly easy to draw possible configurations of 1 or 2 neurons that mimic all the logic gates, discriminators (like a long tailed pairs in old fashioned electronics), delay lines, simple memory and so on. But it is unlikely that this is the root to understanding how neurons act. Networks, parallel feedback loops, glial communities, modules, architecture of different parts of the brain and the like are probably a better level of investigation.
I heard in a few places that a real neuron is nothing like a threshold unit, but more like a complete miniature computer. None of those places expanded on that, though. Could you?
I am not sure that I understand the exact difference between a threshold unit and a miniature computer that you want to shine a light on. Below are some aspects that may be of use to you:
The whole surface of a neuron is not at the same potential (relative to the firing potential). Synapses are many (can be thousands), along branching dendrites, of different types and strengths so that the patterns of input that will cause firing from the dendrite end of the neuron are varied and a large number. This architecture is plastic with synapses being strengthened and weakened by use and by events far away from the neuron. At the axon root synapses are fewer and their effect more individual. If the neuron fires it delivers its signal to many synapses on many other neurons. Again this is plastic.
The potential of the neuron surface is affected by many other things besides other neurons through the synapses. It is affected by electrical and magnetic fields generated by the whole brain (the famous waves etc.). It is affected by the chemical environment such as the concentration of calcium ions. These factors are very changeable depending on the activity of the whole brain, hormone levels, general metabolism etc.
It is fairly easy to draw possible configurations of 1 or 2 neurons that mimic all the logic gates, discriminators (like a long tailed pairs in old fashioned electronics), delay lines, simple memory and so on. But it is unlikely that this is the root to understanding how neurons act. Networks, parallel feedback loops, glial communities, modules, architecture of different parts of the brain and the like are probably a better level of investigation.
I hope this is of some help.