A Mixed-Signal Structured AdEx Neuron for Accelerated Neuromorphic Cores

TL;DR

This paper presents a multi-compartment AdEx neuron circuit for neuromorphic hardware that mimics complex cortical neuron firing patterns and dendritic processes, enhancing computational capabilities.

Contribution

It introduces a novel mixed-signal neuron circuit with dendritic features based on the AdEx model, implemented in 65 nm CMOS for neuromorphic applications.

Findings

Reproduces diverse cortical firing patterns

Emulates sodium, calcium spikes, and NMDA plateau potentials

Enhances computational capabilities of on-chip neurons

Abstract

Here we describe a multi-compartment neuron circuit based on the Adaptive-Exponential I&F (AdEx) model, developed for the second-generation BrainScaleS hardware. Based on an existing modular Leaky Integrate-and-Fire (LIF) architecture designed in 65 nm CMOS, the circuit features exponential spike generation, neuronal adaptation, inter-compartmental connections as well as a conductance-based reset. The design reproduces a diverse set of firing patterns observed in cortical pyramidal neurons. Further, it enables the emulation of sodium and calcium spikes, as well as N-Methyl-D-Aspartate (NMDA) plateau potentials known from apical and thin dendrites. We characterize the AdEx circuit extensions and exemplify how the interplay between passive and non-linear active signal processing enhances the computational capabilities of single (but structured) on-chip neurons.