Bridging the Gap: Balancing Biology and Efficiency in Neural Networks for Robotics

By Dr Silpaja Chandrasekar, PhDReviewed by Susha Cheriyedath, M.Sc.Sep 15 2023

In a paper published in the journal Applied Sciences, researchers explored the intricate relationship between computational efficiency and biological plausibility within spiking neural networks. The focus was on Spiking Neural Network (SNN) as a tool for enabling autonomous behaviors and discussing the potential of neuromorphic computing in bridging synthetic and natural cognition in robotics.

Related Work

Previous research has extensively explored the interplay between computational efficiency and biological plausibility, especially within the domain of SNN. This exploration has paved the way for the development of intelligent systems capable of swift adaptation to dynamic environments. The term "Intelligent" systems pertain to entities with the capacity to rapidly respond to changes in their components, surroundings, or mission objectives. This adaptability relies on efficient information processing, which draws inspiration from the spike-based activity observed in biological neurons.

Proposed Method

Spiking Neural Networks and Neuromorphic Implementation: The neuron is the fundamental computational unit in exploring the core components of SNN modeling and their implementation within neuromorphic systems. A simplified representation of a biological neuron includes dendrites for post-synaptic interactions, soma-generating action potentials (spikes), and an axon with terminals for pre-synaptic interactions.

The various forms of modeling spiking neurons include compartmental models, which dissect the neuron's morphological components and represent their dynamics through coupled differential equations. These models can pose computational challenges beyond cellular-level investigations while offering rich structural details. Neuromorphic hardware frequently employs pointwise models. These models abstract neurons as single points, simplifying computational aspects at the cost of some biological plausibility.

This choice between modeling approaches significantly impacts the trade-off between biological fidelity and computational efficiency in simulating neural systems. Compartmental models capture detailed subcellular interactions but complexity, whereas pointwise models offer computational efficiency with some sacrifice of biological realism. Striking a balance between these factors is pivotal in neuromorphic hardware design and neural network simulations.

Neuromorphic Computing: A Hardware vs. Software Comparison: The choice of computing platform for implementing SNN presents distinct challenges and benefits. Central Processing Units (CPUs) offer flexibility but may struggle with large-scale SNN computations. Graphics Processing Units (GPUs) excel in parallel processing but consume more energy. Field-Programmable Gate Arrays (FPGAs) provide low-latency, low-power operation but have limited resources. Using specialized hardware like neuromorphic chips in neuromorphic computing efficiently manages large-scale SNNs, providing energy efficiency and real-time processing capabilities.

Software platforms like Nengo and Brian2 aid in simulating SNNs on different hardware, which allows researchers to choose the most suitable platform based on their needs and research goals. The Vector Symbolic Architecture (VSA) and the Vector Function Architecture (VFA) extend algebraic operations from vector spaces to functional spaces. This extension enables the creation of high-dimensional, distributed representations that are flexible and context-sensitive. These properties make VFAs an appealing choice for tackling challenges in higher-order cognitive processes. These approaches open the door to energy-efficient and neuromorphic implementations of complex cognitive algorithms.

Integrating SNNs into Cognitive Robotic Systems: A robot is envisioned as an information-processing machine endowed with the ability to plan, perceive, and control its physical actuators. These machines operate within a physical environment that utilizes kinematic and dynamic models to navigate their surroundings, set goals, and make plans. The collaboration between humans and robots in intricate tasks has been investigated, posing an ethical design challenge. This challenge emphasizes the significance of establishing trust between society and robotics by designing robots that adhere to social norms. However, achieving true adaptability and autonomy in robotic systems requires significant progress. 

This progress hinges on three pivotal steps: (i) embracing the biological principles of the traditional robotic perception-planning-action cycle, (ii) embodying self-aware agents with proprioceptive and exteroceptive capabilities in an environment, and (iii) enabling reconfigurability in these embodied self-aware agents.

Finding Balance in AI and Robotics

This paper explores the challenge of balancing computational efficiency and biological realism in AI, robotics, and neuroscience. The initial research on neural networks prioritized algorithms, often sacrificing biological plausibility for efficiency. Recent advancements in neuromorphic hardware have shifted towards greater biological fidelity, but software design challenges persist. The increasing gap between complex neural network behaviors and human comprehension continues to raise concerns about explainability and transparency.

Applications like robotic vision have made substantial advancements, yet they frequently retain a modular nature. They often lack integration across sensory modalities and cognitive functions. The field of cognitive neurorobotics offers a promising path forward. It enables a closer link between neural network activities and behavioral explainability, serving as a testbed for addressing ethical concerns in complex neural systems interpretations and behaviors.

Conclusion

To sum up, this paper examines the intersection of neuroscience and AI by focusing on the balance between biological plausibility and computational efficiency in modeling cognition. SNN emerges as a pivotal tool that bridges the gap between understanding neuroscientific behaviors and modeling cognitive processes in various fields, including brain activity analysis and the embodiment of cognitive behavior in robots. The issue of balancing biological fidelity with computational efficiency has been tackled, and neuromorphic hardware presents a possible resolution to this challenge.

SNN finds applications not only in advanced Electroencephalography (EEG) signal processing but also in neuroprosthetics and brain-computer interfaces. These networks also have a vital role in capturing neuronal behavior and enhancing the neurocognitive capabilities of artificial agents, especially in robotic systems. The provision of a theoretical foundation and computational efficiency for the study of embodied cognition and consciousness also addresses challenges related to neurobiological explainability.