Emulating working memory consolidation with a 1D supramolecular nanofibre-based neuromorphic device†

Abstract

Cognitive activities in the human brain are driven by the processes of learning and forgetting. However, there is yet another process namely consolidation, which stands as an interface for saving important learnt information from forgetting. Consolidation is imperative for the formation of stable, long-term memories and is an integral part of the memory formation process. Despite significant efforts in emulating learning, forgetting, and several synaptic functionalities through various neuromorphic devices, the efforts to understand the consolidation process are insignificant. Among the two forms of consolidation, namely long-term and working memory consolidations, the present study explores the latter that stabilizes transient sensory input and enhances retention by counteracting decay-based forgetting. Herein, a two-terminal optically active resistive neuromorphic device based on 1D supramolecular nanofibres is utilized to emulate and quantify consolidation, basically, in working memory. The phenomenon aligns with mathematical models using two-time constants, drawing parallels with biological mechanisms. Given the excellent optical and humidity response of the nanofibres, the emulation was achieved by employing optical input as stimuli and enabling the modulation of the photoresponse by exposure to different humidities. By defining consolidation as a function of humidity, the study underscores its role as an active control, reinforcing the connection between environmental factors and memory stability. The variation in consolidation was studied during the learning–relearning, change in environment (hydrated and dehydrated state), fatigue, and habituation processes. Notably, a consolidation parameter is defined to quantify the process of consolidation that is an inseparable process of cognition.