“…In this framework, several neuromorphic spiking neural networks (SNNs) based on CMOS technology have been proposed, demonstrating VLSI synaptic circuits with homeostatic neurons (Bartolozzi and Indiveri, 2006 ; Chicca et al, 2014 ; Qiao et al, 2017 ) and reward-based decision-making circuits (Wunderlich et al, 2019 ; Yan et al, 2019 ). At the same time, non-volatile memory devices, such as phase change memory (PCM), have raised considerable interest as promising synaptic connections for neuromorphic computation, thanks to the 3D stacking capability, the low-voltage operation and the ability to serve as embedded non-volatile memory in computing systems (Suri et al, 2012 ; Xu et al, 2020 ; Ren et al, 2021 ). In particular, PCMs have recently demonstrated outstanding multi-level capability (Kuzum et al, 2013 ; Ren et al, 2021 ), which enables continual learning in neural networks (Bianchi et al, 2019 ; Muñoz-Martín et al, 2019 ) and decision making in brain-inspired cognitive systems (Eryilmaz et al, 2014 ).…”