Functional Connectivity of Organic Neuromorphic Devices by Global Voltage Oscillations

Abstract

Global oscillations in the brain synchronize neural populations and lead to dynamic binding between different regions. This functional connectivity reconfigures as needed for the architecture of the neural network, thereby transcending the limitations of its hardwired structure. Despite the fact that it underlies the versatility of biological computational systems, this concept is not captured in current neuromorphic device architectures. Herein, functional connectivity in an array of organic neuromorphic devices connected through an electrolyte is demonstrated. The output of these devices is shown to be synchronized by a global oscillatory input despite the fact that individual inputs are stochastic and independent. This temporal coupling is induced at a specific phase of the global oscillation in a way that is reminiscent of phase locking of neurons to brain oscillations. This demonstration provides a pathway toward new neuromorphic architectural paradigms, where dynamic binding transcends the limitations of structural connectivity, and could enable architectural concepts of hierarchical information flow.

An Iontronic Multiplexer Based on Spatiotemporal Dynamics of Multiterminal Organic Electrochemical Transistors

“…The shared electrolyte between the gates, G n , and the channel allows for "parallel" coupling of the channel with the various gates, G n . [39,40,50] An actual microfabricated device is displayed in Figure 1b.…”

Organic neuromorphic devices: Past, present, and future challenges

“…41 Device arrays were used to simulate higher functions such as orientation selectivity, homeoplasticity, and functional connectivity by global voltage oscillations (as described in the van de Burgt and Gkoupidenis 30 article in this issue). [42][43][44] In another approach, the article by Perez and Shaheen in this issue 90 presents a design strategy for using electrochemical transistors in neuromorphic circuits aimed at demonstrating Boolean and reversible logic. It utilizes neuronal circuit structures similar to those of Emelyanov et al, 37 but based solely on three-terminal electrochemical devices without the need for memristors or CMOS transistors.…”

Organic materials and devices for brain-inspired computing: From artificial implementation to biophysical realism

“…The devices are functionally connected through the global oscillation. 126,127 Note: PEDOT:PSS, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate).…”

“…Due to the inherent capability of a device array to operate in common electrolytes, the response of the device array when receiving stochastic input signals can be synchronized with a global oscillatory input signal (Figure 4d). 126,127 Although not physically connected with metal lines, such devices are functionally connected through the global oscillatory input as they share a common correlation over time. In the brain, apart from actual structurally connected networks, networks also exist that share common activity over short periods of time and are thus functionally connected.…”