# Excitable behaviors

## TL;DR

This paper explores the concept of excitability in neurons as behaviors of open systems, emphasizing input-output characteristics and proposing new questions for non-linear system theory inspired by neurophysiology.

## Contribution

It redefines excitability as a behavior of open systems and connects circuit theory with neurophysiological insights, proposing novel research questions.

## Key findings

- Input-output characterization via local sensitivity
- Modeling of excitability as open systems
- New questions for non-linear system theory

## Abstract

This chapter revisits the concept of excitability, a basic system property of neurons. The focus is on excitable systems regarded as behaviors rather than dynamical systems. By this we mean open systems modulated by specific interconnection properties rather than closed systems classified by their parameter ranges. Modeling, analysis, and synthesis questions can be formulated in the classical language of circuit theory. The input-output characterization of excitability is in terms of the local sensitivity of the current-voltage relationship. It suggests the formulation of novel questions for non-linear system theory, inspired by questions from experimental neurophysiology.