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Modulation Channels in Biomimic Artificial Neurons. Richard B. Wells. The Biomimic Concept. Purpose: Lay Out the General Architecture for Biomimic Neurons Biomimic is a Subset of Biomimetic Biomimic = Mimicking the Neuron or Glial Cell The Artificial Neuron as a State Machine
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Modulation Channels in Biomimic Artificial Neurons Richard B. Wells
The Biomimic Concept • Purpose: Lay Out the General Architecture for Biomimic Neurons • Biomimic is a Subset of Biomimetic • Biomimic = Mimicking the Neuron or Glial Cell • The Artificial Neuron as a State Machine • Classical Artificial Neurons After Training Are “Combinational Analog Logic” • Biological Neurons Are Better Modeled as Analog State Machines • “Information relates not so much to what you do say as to what you could say • Warren Weaver, 1964
Short-Term vs. Long-Term Adaptation • Conventional Adaptation = LTP, LTD • Modulation = Short-Term Adaptation • Short-Term Modulations => The Neuron as a State Machine • “In order to understand the style of computation practiced by nervous systems, we must study their hardware.” • Christof Koch, 1999
Three Basic Modulation Mechanisms in Biological Neurons • Voltage-Gated Ionic Channels (VGCs) • Classical Hodgkin-Huxley Model • Generally NOT “Inputs” (NMDA = ?) • Ionotropic Channels -Synaptic Signal Inputs • Metabotropic Receptors – “Control Inputs” • “Intrinsic” vs. “Extrinsic” Information?
Voltage-Gated Channels • VGCs Most Directly Control the Action Potential • They Are “Feedback Circuits” Mediated Through the Integration of Membrane Potential • They Occur in Great Variety but Follow A Generalized Architectural Scheme
Ionotropic Channels • Principal Transmission Inputs of Neuron • IC s Recruit VGCs Through PSPs
The IC Synapse is a State Machine • Basic Mode is a Non-Retriggerable Monostable Multivibrator • Tetanic Facilitation = Input-Dependent Synaptic Weight • Delay, Conduction Time Can Be Modulated (Phosphorylation)
Metabotropic Receptor Processes • Their Role is Entirely Modulatory • 2nd Messenger Processes Essential for Stabilization of Synaptic Weight Changes (LTP, LTD) • Indirect Effects on Ion Current Flow, Generation of Retrograde Messengers, Modulation of IC Neurotransmitter Actions • They Have Traditionally Been Ignored in Artificial Neurons