Learning Spike Time Codes Through Morphological Learning With Binary Synapses

• Published in: IEEE transaction on neural networks and learning systems 2016-07, Vol.27 (7), p.1572-1577
• Main Authors: Roy, Subhrajit, Phyo Phyo San, Hussain, Shaista, Lee Wang Wei, Basu, Arindam
• Format: Article
• Language: English
• Subjects: Accuracy; Action Potentials; Algorithms; Animals; Artificial neural networks; Binary synapse; Classification; dendrites; Dendritic structure; Hardware; Humans; Learning; Learning systems; Models, Neurological; Neural networks; Neurons; Neurons - physiology; plasticity; Quantization (signal); Robot sensing systems; Spikes; spiking neuron; Synapses; Synapses - physiology; tempotron; Training
• ISSN: 2162-237X; 2162-2388
• DOI: 10.1109/TNNLS.2015.2447011

In this brief, a neuron with nonlinear dendrites (NNLDs) and binary synapses that is able to learn temporal features of spike input patterns is considered. Since binary synapses are considered, learning happens through formation and elimination of connections between the inputs and the dendritic branches to modify the structure or morphology of the NNLD. A morphological learning algorithm inspired by the tempotron, i.e., a recently proposed temporal learning algorithm is presented in this brief. Unlike tempotron, the proposed learning rule uses a technique to automatically adapt the NNLD threshold during training. Experimental results indicate that our NNLD with 1-bit synapses can obtain accuracy similar to that of a traditional tempotron with 4-bit synapses in classifying single spike random latency and pairwise synchrony patterns. Hence, the proposed method is better suited for robust hardware implementation in the presence of statistical variations. We also present results of applying this rule to real-life spike classification problems from the field of tactile sensing.