Adaptive Plasticity in Spiking Neuron Networks

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Solution Overview

Problem

Existing plasticity implementations in spiking neural networks do not effectively adapt to changing input characteristics, limiting network behavior and learning performance.

Innovation Solution

The implementation of adaptive plasticity mechanisms that dynamically adjust connection efficacies based on similarity measures between neuron outputs and inputs, using methods such as cross-correlograms and STDP rules to determine long-term potentiation and depression components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing plasticity implementations are used in spiking neural networks, then the network can operate with fixed connection efficacies, but the network cannot effectively adapt to changing input characteristics

Engineering Contradiction:
Improveadaptability to changing input characteristicsVSAvoidcomplexity of plasticity implementation
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic plasticity mechanisms where connection efficacies are not fixed but continuously adjusted based on spike timing relationships. The STDP (spike-timing-dependent plasticity) rule dynamically modifies synaptic weights according to the temporal order of pre-synaptic and post-synaptic spikes, enabling the network to adapt to changing input characteristics while maintaining a relatively simple implementation framework

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of connection efficacy dynamically through plasticity mechanisms. By modifying synaptic weights based on spike timing correlations and similarity measures, the system enables adaptability to varying input patterns without requiring complete reconfiguration of the network architecture, thus balancing adaptability improvement with controlled complexity increase

Inventive Principle:
Principle #35Parameter changes

2Productivity

If adaptive plasticity mechanisms are implemented to improve learning performance, then convergence speed increases, but computational complexity increases

Engineering Contradiction:
Improvelearning convergence speedVSAvoidcomputational complexity of plasticity mechanisms
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies partial action by implementing plasticity updates only when specific conditions are met (e.g., when spike timing correlations exceed thresholds or when similarity measures indicate meaningful patterns). This selective updating approach accelerates convergence by focusing computational resources on critical learning moments while avoiding unnecessary computations during stable or redundant states, thus improving productivity without proportionally increasing overall computational complexity

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If fixed connection efficacies are used, then the network structure remains simple, but the network cannot learn temporally stable patterns

Engineering Contradiction:
Improvelearning of temporally stable patternsVSAvoidcomplexity of connection efficacy adjustment
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback mechanisms where the network monitors its own spike timing patterns and uses this information to adjust connection efficacies. The STDP rule provides continuous feedback based on whether pre-synaptic spikes precede or follow post-synaptic spikes, enabling the network to learn temporally stable patterns by reinforcing causally relevant connections while pruning spurious correlations, thus improving reliability through structured feedback rather than complex ad-hoc adjustments

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS9183493B2Adaptive plasticity apparatus and methods for spiking neuron network
Publication Date: 2015.11.10 BRAIN CORP
  • US9183493B2 patent drawing
  • US9183493B2 patent drawing
  • US9183493B2 patent drawing

AI summary

Apparatus and methods for plasticity in a spiking neuron network. In one implementation, a plasticity mechanism is configured based on a similarity measure between neuron post-synaptic and pre-synaptic activity. The similarity measure may comprise a cross-correlogram between the output spike train and input spike train, determined over a plasticity window. Several correlograms, corresponding to individual input connections delivering pre-synaptic input, may be combined. The combination may comprise for example a weighted average. The averaged correlograms may be used to construct the long term potentiation component of the plasticity. The long term depression component of the plasticity may comprise e.g., a monotonic function based on a statistical parameter associated with the adaptively determined long term potentiation component.