| Neuromorphic systems are inspired by the structure, | | | | transistor. |
| function and plasticity of biological nervous systems. | | | | Artificial neuromorphic systems are applied in the |
| They are artificial neural systems that mimic | | | | areas of vision, hearing, olfaction, touch, learning, |
| algorithmic behavior of the biological animal systems | | | | decision-making, pattern recognition among others to |
| through efficient adaptive and intelligent control | | | | develop autonomous systems in robotics, vehicle |
| techniques. | | | | guidance and traffic control, pattern recognizers etc. |
| They are designed to adapt, learn from their | | | | As the systems mature, human parts replacements |
| environments, and make decisions like biological | | | | would become a major application area. The |
| systems and not to perform better than them. | | | | fundamental principle is by observing how biological |
| There are no efforts to eliminate deficiencies inherent | | | | systems perform these functions robust artificial |
| in biological systems. | | | | systems are designed. |
| This field, called neuromorphic engineering, is evolving | | | | So the philosophy of neuromorphic engineering is to |
| a new era in computing with a great promise for | | | | utilize algorithmic inspiration of biological systems to |
| future medicine, healthcare delivery and industry. It | | | | engineer artificial systems. It is a kind of technology |
| relies on plenty of experiences which nature offers | | | | transfer from biology to engineering that involves the |
| to develop functional, reliable and effective artificial | | | | understanding of the functions and forms of the |
| systems. Neuromorphic computational circuits, | | | | biological systems and consequent morphing into |
| designed to mimic biological neurons, are primitives | | | | silicon chips. |
| based on the optical and electronic properties of | | | | For instance, the study of the structure of the |
| semiconductor materials. | | | | muscle in an animal inspires the creation of locomotive |
| Dr. Carver Mead, professor emeritus of California | | | | robots that do not rely on heavy and power hungry |
| Institute of Technology (Caltech), Pasadena | | | | servo motors. The fundamental thing is to |
| pioneered this field. He reasoned that biological | | | | understand how biological nerve tissues represent, |
| evolutionary trends over millions of years have | | | | communicate and process information. That would |
| produced organisms that engineers can study to | | | | become the prelude to engineer electronic devices. |
| develop better artificial systems. By giving senses and | | | | Understanding the biologically algorithms of animals |
| sensory-based behavior to machines, these systems | | | | are vital and fundamental to reverse engineer the |
| can possibly compete with human senses and brings | | | | biological systems information representations and |
| an intersection between biology, computer science | | | | then develop systems that use these |
| and electrical engineering. | | | | representations in their operations. |
| Neuromorphic systems depend on parallel collective | | | | The fundamental biological unit mimicked in the design |
| computation, adaptation, learning and memory | | | | of neuromorphic systems is the neurons. Animal brain |
| implemented locally at each stage of processing | | | | is composed of these individual units of computation, |
| within the artificial neurons (the computational | | | | called neurons and the neurons are the elementary |
| elements). | | | | signaling parts of the nervous systems. Neurons, |
| Analog circuits, electrical circuits operated with | | | | which have common shape, produce electricity or |
| continuous varying signals, are used to implement | | | | chemical signals to communicate with other |
| these algorithmic processes with transistors operated | | | | neighboring ones. |
| in the sub-threshold or weak inversion region (a | | | | Though these neurons are similar in shape, different |
| region of operation in which transistors are designed | | | | connections with each other, muscles and receptors |
| to conduct current though the gate voltage is slightly | | | | produce different computational results in biological |
| lower than the minimum voltage, called threshold | | | | systems: locomotive control, perception, sensory |
| voltage, required for normal conduction to take place) | | | | processing, auditory processing etc. Neuron is made |
| where they exhibit exponential current-voltage | | | | of made up of input area (the dendrite) and output |
| characteristics and low currents. | | | | area (the axion) and is connected with other neurons |
| This circuit paradigm produces high density and low | | | | by synapses. |
| power implementations of some functions that are | | | | Since neurons are the basic cells of the nervous |
| computationally intensive when compared with other | | | | systems of all kinds of animals, building silicon neurons |
| paradigms (triode and saturation operational regions). | | | | (or neuromorphs) endowed with fundamental life-like |
| A triode region is operating transistor with gate | | | | characteristics, could enable the emulation or modeling |
| voltage above the threshold voltage but with the | | | | of the neural networks in biological nervous systems. |
| drain-source voltage lower than the difference | | | | By examining the retina for instance, artificial neurons |
| between the gate-source voltage and threshold | | | | that mimic the retinal neurons and chemistry are |
| voltage. For saturation region, the gate voltage is still | | | | fabricated on silicon (most common material), gallium |
| above the threshold voltage but with the | | | | arsenide (GaAs) or possibly prospective organic |
| drain-source voltage above the difference between | | | | semiconductor materials. |
| the gate-source voltage and threshold voltage. | | | | In conclusion, it may not have changed the world, but |
| Transistor has four terminals: drain, gate, source and | | | | the prospects of neuromorphics in medicine are many |
| bulk. Current flows between the drain and the source | | | | and could possibly herald the era of bio-grade artificial |
| when enough voltage is applied through the gate that | | | | electronics human organs. |
| enables conduction. The bulk is the body of the | | | | |