{"id":8663,"date":"2016-06-28T01:24:04","date_gmt":"2016-06-28T01:24:04","guid":{"rendered":"http:\/\/www.kurzweilai.net\/?p=282677"},"modified":"2016-06-30T05:33:27","modified_gmt":"2016-06-30T05:33:27","slug":"artificial-synapse-said-to-rival-biological-synapses-in-energy-consumption-and-function","status":"publish","type":"post","link":"https:\/\/hoo.central12.com\/fugic\/2016\/06\/28\/artificial-synapse-said-to-rival-biological-synapses-in-energy-consumption-and-function\/","title":{"rendered":"Artificial synapse said to rival biological synapses in energy consumption and function"},"content":{"rendered":"
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Schematic of biological neuronal network and an organic nanowire (ONW) synaptic transistor (ST) that emulates a biological synapse. The yellow conductive lines and probe (A\u2032) mimic an axon (A) that delivers presynaptic spikes from a pre-neuron to the presynaptic membrane. The mobile ions in the ion gel move in the electrical field, analogous to the biological neuron transmitters in the synaptic cleft; the field later induces an excitatory postsynaptic current (EPSC, light blue line) in the biological dendrite (B). An ONW (B\u2032) combined with a drain electrode (yellow surface) mimics a biological dendrite (B). EPSC (light green line) is generated in the ONW in response to presynaptic spikes and is delivered to a post-neuron through connections to the drain electrode. (credit: Wentao Xu et al.\/Science Advances)<\/p><\/div>\n

An artificial synapse that emulates a biological synapse while requiring less energy has been developed by Pohang University Of Science & Technology (POSTECH<\/a>) researchers* in Korea.<\/p>\n

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Energy consumption in Joules per synaptic event of currently available synaptic devices.*** NG, nanogap; PCM, phase change memory; RRAM, resistive switching random access memory. (credit: Wentao Xu et al.\/Science Advances)<\/p><\/div>\n

A human synapse consumes an extremely small amount of energy (~10 fJ or femtojoules** per synaptic event).<\/p>\n

The researchers have fabricated an organic nanofiber (ONF), or organic nanowire (ONW), electronic device that emulates the important working principles and energy consumption of biological synapses while requiring only ~1 fJ per synaptic event. The ONW also emulates the morphology (form) of a synapse.<\/p>\n

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Array of 144 ONW STs (organic nanowire synaptic transistors) fabricated on a 4-inch silicon wafer. Inset: Scanning electron microscopy (SEM) image of a typical ONW with a diameter of 200 nm. (credit: Wentao Xu et al.\/Science Advances)<\/p><\/div>\n

The morphology of ONFs is similar to that of nerve fibers, which form crisscrossing grids to enable the high memory density of a human brain. The researchers say the highly-aligned ONFs can be massively produced with precise control over alignment and dimension; and this morphology may make possible the future construction of the high-density memory of a neuromorphic (brain-form-emulating) system.****<\/p>\n

The researchers say they have emulated important working principles of a biological synapse, such as paired-pulse facilitation (PPF), short-term plasticity (STP), long-term plasticity (LTP), spike-timing dependent plasticity (STDP), and spike-rate dependent plasticity (SRDP).<\/p>\n

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The ONW STs are three-terminal devices. Input voltage pulses that emulate presynaptic spikes from a pre-neuron are applied to the metal probe, which functions as a gate electrode. The input pulses cause ions to migrate in the ion gel, causing a change in the source-drain (yellow rectangles) current flowing through the semiconducting ONW (red). The output current signal — which emulates post-synaptic current flowing to a post-neuron in a biological synapse — is measured (during characterization) by recording the drain current. (credit: Wentao Xu et al.\/Science Advances)<\/p><\/div>\n

The artificial synapse devices provide a new research direction in neuromorphic electronics and open a new era of organic electronics with high memory density and low energy consumption, the researchers claim. Potential applications include neuromorphic computing systems, AI systems for self-driving cars, analysis of big data, cognitive systems, robot control, medical diagnosis, stock-trading analysis, remote sensing, and other smart human-interactive systems and machines in the future, they suggest.<\/p>\n

This research was supported by the Pioneer Research Center Program and Center for Advanced Soft-Electronics as a Global Frontier Project, funded by the Korean Ministry of Science, ICT, and Future Planning.<\/p>\n

The research was published an open-access paper in\u00a0Science Advances<\/em>, a new sister journal of\u00a0Science<\/em>.<\/p>\n

* Prof. Tae-Woo Lee, Wentao Xu, and Sung-Yong Min, PhD, with the Dept. of Materials Science and Engineering at POSTECH<\/em><\/p>\n

** A fJ (femtojoule) is 10-15<\/sup> Joule (one watt-second).\u00a0<\/em><\/p>\n

*** ~1014<\/sup> synapses.<\/p>\n

**** Previous attempts to realize synaptic functions in single electronic devices include resistive random access memory (RRAM), phase change memory (PCM), conductive bridges, and synaptic transistors.<\/p>\n

\n

Abstract of\u00a0Organic core-sheath nanowire artificial synapses with femtojoule energy consumption<\/em><\/h4>\n

Emulation of biological synapses is an important step toward construction of large-scale brain-inspired electronics. Despite remarkable progress in emulating synaptic functions, current synaptic devices still consume energy that is orders of magnitude greater than do biological synapses (~10 fJ per synaptic event). Reduction of energy consumption of artificial synapses remains a difficult challenge. We report organic nanowire (ONW) synaptic transistors (STs) that emulate the important working principles of a biological synapse. The ONWs emulate the morphology of nerve fibers. With a core-sheath\u2013structured ONW active channel and a well-confined 300-nm channel length obtained using ONW lithography, ~1.23 fJ per synaptic event for individual ONW was attained, which rivals that of biological synapses. The ONW STs provide a significant step toward realizing low-energy\u2013consuming artificial intelligent electronics and open new approaches to assembling soft neuromorphic systems with nanometer feature size.<\/p>\n","protected":false},"excerpt":{"rendered":"

An artificial synapse that emulates a biological synapse while requiring less energy has been developed by Pohang University Of Science & Technology (POSTECH) researchers* in Korea. A human synapse consumes an extremely small amount of energy (~10 fJ or femtojoules** per synaptic event). The researchers have fabricated an organic nanofiber (ONF), or organic nanowire (ONW), […]<\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[49,48,43],"tags":[],"class_list":["post-8663","post","type-post","status-publish","format-standard","hentry","category-cognitive-scienceneuroscience","category-electronics","category-news"],"_links":{"self":[{"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/posts\/8663"}],"collection":[{"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/comments?post=8663"}],"version-history":[{"count":4,"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/posts\/8663\/revisions"}],"predecessor-version":[{"id":8719,"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/posts\/8663\/revisions\/8719"}],"wp:attachment":[{"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/media?parent=8663"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/categories?post=8663"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hoo.central12.com\/fugic\/wp-json\/wp\/v2\/tags?post=8663"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}