PMID- 30374283 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20201001 IS - 1662-4548 (Print) IS - 1662-453X (Electronic) IS - 1662-453X (Linking) VI - 12 DP - 2018 TI - On Practical Issues for Stochastic STDP Hardware With 1-bit Synaptic Weights. PG - 665 LID - 10.3389/fnins.2018.00665 [doi] LID - 665 AB - In computational neuroscience, synaptic plasticity learning rules are typically studied using the full 64-bit floating point precision computers provide. However, for dedicated hardware implementations, the precision used not only penalizes directly the required memory resources, but also the computing, communication, and energy resources. When it comes to hardware engineering, a key question is always to find the minimum number of necessary bits to keep the neurocomputational system working satisfactorily. Here we present some techniques and results obtained when limiting synaptic weights to 1-bit precision, applied to a Spike-Timing-Dependent-Plasticity (STDP) learning rule in Spiking Neural Networks (SNN). We first illustrate the 1-bit synapses STDP operation by replicating a classical biological experiment on visual orientation tuning, using a simple four neuron setup. After this, we apply 1-bit STDP learning to the hidden feature extraction layer of a 2-layer system, where for the second (and output) layer we use already reported SNN classifiers. The systems are tested on two spiking datasets: a Dynamic Vision Sensor (DVS) recorded poker card symbols dataset and a Poisson-distributed spike representation MNIST dataset version. Tests are performed using the in-house MegaSim event-driven behavioral simulator and by implementing the systems on FPGA (Field Programmable Gate Array) hardware. FAU - Yousefzadeh, Amirreza AU - Yousefzadeh A AD - Instituto de Microelectronica de Sevilla (IMSE-CNM), CSIC and Universidad de Sevilla, Sevilla, Spain. FAU - Stromatias, Evangelos AU - Stromatias E AD - Instituto de Microelectronica de Sevilla (IMSE-CNM), CSIC and Universidad de Sevilla, Sevilla, Spain. FAU - Soto, Miguel AU - Soto M AD - Instituto de Microelectronica de Sevilla (IMSE-CNM), CSIC and Universidad de Sevilla, Sevilla, Spain. FAU - Serrano-Gotarredona, Teresa AU - Serrano-Gotarredona T AD - Instituto de Microelectronica de Sevilla (IMSE-CNM), CSIC and Universidad de Sevilla, Sevilla, Spain. FAU - Linares-Barranco, Bernabe AU - Linares-Barranco B AD - Instituto de Microelectronica de Sevilla (IMSE-CNM), CSIC and Universidad de Sevilla, Sevilla, Spain. LA - eng PT - Journal Article DEP - 20181015 PL - Switzerland TA - Front Neurosci JT - Frontiers in neuroscience JID - 101478481 PMC - PMC6196279 OTO - NOTNLM OT - feature extraction OT - neuromorphic systems OT - spike timing dependent plasticity OT - spiking neural networks OT - stochastic learning EDAT- 2018/10/31 06:00 MHDA- 2018/10/31 06:01 PMCR- 2018/01/01 CRDT- 2018/10/31 06:00 PHST- 2017/12/05 00:00 [received] PHST- 2018/09/04 00:00 [accepted] PHST- 2018/10/31 06:00 [entrez] PHST- 2018/10/31 06:00 [pubmed] PHST- 2018/10/31 06:01 [medline] PHST- 2018/01/01 00:00 [pmc-release] AID - 10.3389/fnins.2018.00665 [doi] PST - epublish SO - Front Neurosci. 2018 Oct 15;12:665. doi: 10.3389/fnins.2018.00665. eCollection 2018.