Re-activatible Inter-postsynaptic Functional Link Circuit
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Solution Overview
Problem
Existing electronic neural circuits fail to simulate the functional relationships between the postsynaptic terminals of two closely located synapses, which are crucial for associative learning and memory retrieval, and do not accurately replicate the synaptic delay and 'all or none' action potential generation mechanisms.
Innovation Solution
An electronic circuit system is developed that simulates the formation and re-activation of inter-postsynaptic functional links between postsynaptic terminals using diodes and resistor-capacitor combinations to mimic synaptic delay, and voltage comparators to model the 'all or none' action potential phenomenon, allowing for the creation of reversible links with adjustable life-spans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electronic circuits are designed to simulate synaptic transmission, then the ability to model neural network properties is improved, but the complexity of the circuit design increases
Solution Approach 1:
The circuit is divided into distinct functional modules: input terminals with diodes for unidirectional signal flow, resistor-capacitor networks for synaptic delay simulation, voltage comparators for action potential generation, and output terminals. Each module independently performs a specific neural function, making the overall complex system manageable and adaptable.
Solution Approach 2:
Resistor-capacitor networks serve as intermediary elements between input and output terminals, mediating the signal transmission by introducing synaptic delay. The capacitors charge and discharge to simulate the temporal dynamics of synaptic transmission, while resistors control the time constant, acting as mediators that transform electrical signals into biologically realistic neural responses.
2Reliability
If the circuit accurately replicates synaptic delay of 1-2 milliseconds, then the biological fidelity is improved, but the response time of the circuit increases
Solution Approach 1:
The synaptic delay parameter is precisely controlled by adjusting the resistance and capacitance values in the RC networks. By changing the time constant (τ = RC), the circuit can accurately replicate the 1-2 millisecond synaptic delay observed in biological systems. This parameter adjustment allows faithful simulation of neural transmission timing without requiring physical redesign of the circuit architecture.
3Measurement precision
If voltage comparators are used to model 'all or none' action potential generation, then the accuracy of neural activation modeling is improved, but the device complexity increases
Solution Approach 1:
The voltage comparator circuit copies the threshold-based activation mechanism of biological neurons into the electronic domain. When the summed input voltage at the postsynaptic terminal reaches the threshold voltage set by the reference input to the comparator, the output switches states, accurately replicating the all-or-none action potential generation. This copying approach achieves high modeling accuracy using a single integrated comparator component.
4Adaptability or versatility
If functional links between postsynaptic terminals are made re-activatible, then the simulation of memory retrieval is improved, but the circuit stability decreases
Solution Approach 1:
The functional links between postsynaptic terminals are designed to be dynamically re-activatable rather than statically fixed. Capacitors maintain charge states that represent formed functional links, and these links can be re-activated by subsequent neural activity. The circuit transitions between stable states (no activation, activation, and re-activation), allowing simulation of memory retrieval while maintaining overall circuit stability through controlled state transitions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively replicates the neural network's properties, enabling the simulation of neurotransmission and motor neuron activation, allowing for the testing of emerging systems properties and potentially contributing to the development of artificial intelligence by accurately modeling associative learning and memory retrieval processes.
Implementation Method 1
resistor-capacitor combinations to mimic synaptic delay
Implementation Method 2
Since synaptic function takes place with a synaptic delay of neurotransmission of 1 to 2 milliseconds
Implementation Method 3
this function is carried out by a voltage comparator in the circuit that compares the integrated signal with a threshold signal
Implementation Method 4
Unidirectional flow of nerve conduction at the synapses is achieved by using diodes
Data Source
AI summary
An electronic neuronal circuit system to model the interaction between the postsynaptic terminal of a first synapse between two neurons and the postsynaptic terminal of a second synapse between two neurons includes comparators to model the presynaptic neurons of the synapses, plurality of three diodes connected to the comparators to model synapses, an AND gate and latch to model the formation of functional link between the postsynaptic terminals, and timer-controlled latches for controlling the life-span of the inter-postsynaptic functional link, durations of re-activation of inter-postsynaptic functional link and flow of activity through the output postsynaptic dendritic terminals.