Artificial Consciousness/Neural Correlates/Synaptic Models/Membrane Replacement Model
Membrane Replacement Model
[edit | edit source]The Neuron, is a squishy sack of chemicals, as one Neuroscientist described it to me. But mostly what it is, is a digestive system that takes nutrients and breaks them down into smaller structures releasing the energy and transforming it into useful forms that can be used to drive cellular processes. If we accept this definition, then we have to accept that part of the nature of the Neuron, and every other cell in the Universe is that it is constantly digesting itself.
Structures like the cellular membrane that are important to its very survival, must therefore have mechanisms that service them and remove the partially digested components and replace them with new components. It is unfortunate but this means that the cellular membrane is constantly being rebuilt, with the effect that the survival of synaptic sensitive patches, adds a complication to a survival trait.
Although we don't yet know exactly what is involved, if only because we don't yet know which questions to ask, evidence of ion channel storage at levels below the surface of the cell, suggest that what might be happening, is that synapses are replaced by the membrane replacement mechanism, along with the rest of the membrane.
This opens up the question, of whether or not ion channel integration in the sensitive patch is also altered in the Membrane Replacement Mechanism, or in some other manner. Evidence from the Neurochemists suggests that proteins some call tags, become associated with particularly active synapses, This has been proposed as a method by which weights can be adjusted, if the protein tag, is consumed during the Membrane Replacement Mechanism, and as a result, new ion channels are added to the synapse, then the effecitive weight of that synapse is increased. Such a tag is called an ephemeral tag, because it lasts only until the next time the membrane is replaced. On the other side of the coin, if the membrane replacement mechanism has the ability to detect the denaturing of an ion channel, it can remove ion channels that have been digested and no longer work, thus resulting in a gradual loss of weight over time, in every synapse that is not active.
The combination of these two factors determines how quickly a synapse can learn. The more ephemeral tags that a sensitive patch can sequester, and the faster the membrane is replaced the faster the synapse weights can be adjusted.