The role of pre-synaptic DC bias is investigated in three-terminal organic neuromorphic architectures based on Electrolyte gated Organic Transistors - EGOTs. By means of presynaptic offset it is possible to finely control the number of discrete conductance states in short-term plasticity experiments, to obtain, at will, both depressive and facilitating response in the same neuromorphic device and to set the ratio between two subsequent pulses in paired-pulse experiments. The charge dynamics leading to these important features are discussed in relationship with macroscopic device figures of merit such as conductivity and transconductance, establishing a novel key enabling parameter in devising the operation of neuromorphic organic electronics.

The next generation of brain-machine interfaces are envisioned to couple signal transduction, filtering, and sorting on board with minimum power consumption and maximum bio-integrability. These functional needs shall be mandatorily met in order to design efficient closed-loop brain-machine interfaces aimed at treating and monitoring various disorders of the central and peripheral nervous system. Here, we highlight the pivotal role organic bioelectronics may have in the contextual development of all these three desiderata, by demonstrating a modular organic-electronics circuit towards real-time signal filtering. The inherent filtering capabilities of electrolyte-gated organic transistor are tuned via adjustment of operational conditions and benchmarked in an electromyography experiment. Additionally, a whole-organic signal processing circuitry is presented, coupling such transistors with ad hoc designed organic passive components. This provides the possibility to sort complex signals into their constitutive frequency components in real time, thereby delineating innovative strategies to devise organic-based functional building-blocks for brain-machine interfaces.