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Emerging neuromorphic computing architectures: (a) traditional von Neumann Computing System (b) Distributive Neuromorphic Computing Architecture (c) Cluster Neuromorphic Computing Architecture (d) Associative Neuromorphic Computing Architecture.
Source publication
![Figure 3-1: Increase trend of the dataset and neural network sizes [8]](profile/Hongyu-An/publication/348437192/figure/fig5/AS:979550817239044@1610554522139/1-Increase-trend-of-the-dataset-and-neural-network-sizes-8_Q320.jpg)
Human brains can complete numerous intelligent tasks, such as pattern recognition, reasoning, control and movement, with remarkable energy efficiency (20 W). In contrast, a typical computer only recognizes 1,000 different objects but consumes about 250 W power [1]. This performance significant differences stem from the intrinsic different structure...
Citations
... A neuromorphic system emulates nervous systems, such as human brains, aiming at implementing Artificial Intelligence [20][21][22][23][24][25]. Human brains have the capability of executing sophisticated missions in unbelievably ultra-low energy. ...
Fear conditioning is a behavioral paradigm of learning to predict aversive events. It is a form of associative learning that memorizes an undesirable stimulus (e.g., an electrical shock) and a neutral stimulus (e.g., a tone), resulting in a fear response (such as running away) to the originally neutral stimulus. The association of concurrent events is implemented by strengthening the synaptic connection between the neurons. In this paper, with an analogous methodology, we reproduce the classic fear conditioning experiment of rats using mobile robots and a neuromorphic system. In our design, the acceleration from a vibration platform substitutes the undesirable stimulus in rats. Meanwhile, the brightness of light (dark vs. light) is used for a neutral stimulus, which is analogous to the neutral sound in fear conditioning experiments in rats. The brightness of the light is processed with sparse coding in the Intel Loihi chip. The simulation and experimental results demonstrate that our neuromorphic robot successfully, for the first time, reproduces the fear conditioning experiment of rats with a mobile robot. The work exhibits a potential online learning paradigm with no labeled data required. The mobile robot directly memorizes the events by interacting with its surroundings, essentially different from data-driven methods.
Introduction
Parkinson’s disease (PD) is a neurodegenerative disorder affecting millions of patients. Closed-Loop Deep Brain Stimulation (CL-DBS) is a therapy that can alleviate the symptoms of PD. The CL-DBS system consists of an electrode sending electrical stimulation signals to a specific region of the brain and a battery-powered stimulator implanted in the chest. The electrical stimuli in CL-DBS systems need to be adjusted in real-time in accordance with the state of PD symptoms. Therefore, fast and precise monitoring of PD symptoms is a critical function for CL-DBS systems. However, the current CL-DBS techniques suffer from high computational demands for real-time PD symptom monitoring, which are not feasible for implanted and wearable medical devices.
Methods
In this paper, we present an energy-efficient neuromorphic PD symptom detector using memristive three-dimensional integrated circuits (3D-ICs). The excessive oscillation at beta frequencies (13–35 Hz) at the subthalamic nucleus (STN) is used as a biomarker of PD symptoms.
Results
Simulation results demonstrate that our neuromorphic PD detector, implemented with an 8-layer spiking Long Short-Term Memory (S-LSTM), excels in recognizing PD symptoms, achieving a training accuracy of 99.74% and a validation accuracy of 99.52% for a 75%–25% data split. Furthermore, we evaluated the improvement of our neuromorphic CL-DBS detector using NeuroSIM. The chip area, latency, energy, and power consumption of our CL-DBS detector were reduced by 47.4%, 66.63%, 65.6%, and 67.5%, respectively, for monolithic 3D-ICs. Similarly, for heterogeneous 3D-ICs, employing memristive synapses to replace traditional Static Random Access Memory (SRAM) resulted in reductions of 44.8%, 64.75%, 65.28%, and 67.7% in chip area, latency, and power usage.
Discussion
This study introduces a novel approach for PD symptom evaluation by directly utilizing spiking signals from neural activities in the time domain. This method significantly reduces the time and energy required for signal conversion compared to traditional frequency domain approaches. The study pioneers the use of neuromorphic computing and memristors in designing CL-DBS systems, surpassing SRAM-based designs in chip design area, latency, and energy efficiency. Lastly, the proposed neuromorphic PD detector demonstrates high resilience to timing variations in brain neural signals, as confirmed by robustness analysis.
The human brain is the most powerful computational machine in this world that has inspired artificial intelligence for many years. One of the latest outcomes of the reverse engineering neural system is deep learning, which emulates the multiple-layer structure of biological neural networks. Deep learning has achieved a variety of unprecedented successes in a large range of cognitive tasks. However, accompanied by the achievements, the shortcomings of deep learning are becoming more and more severe. These drawbacks include the demand for massive data, energy inefficiency, incomprehensibility, etc. One of the innate drawbacks of deep learning is that it implements artificial intelligence through the algorithms and software alone with no consideration of the potential limitations of computational resources. On the contrary, neuromorphic computing, also known as brain-inspired computing, emulates the biological neural networks through a software and hardware co-design approach and aims to break the shackles from the von Neumann architecture and digital representation of information within it. Thus, neuromorphic computing offers an alternative approach for next-generation AI that balances computational complexity, energy efficiency, biological plausibility, and intellectual competence. This chapter aims to comprehensively introduce neuromorphic computing from the fundamentals of biological neural systems, neuron models, to hardware implementations. Lastly, critical challenges and opportunities in neuromorphic computing are discussed.KeywordsNeuromorphic computingSpiking neural networksArtificial intelligenceSilicon neuronsMemristive synapseBiological neural networksNeuromorphic chips
