On discovering functions in actin filament automata

TL;DR

This paper models actin filaments as automaton networks with binary and ternary states, demonstrating their potential for computational mapping and function discovery through simulation of excitation dynamics and input-output port perturbations.

Contribution

It introduces a novel automaton model of actin filaments capable of mapping binary functions, revealing new computational capabilities of biological filament networks.

Findings

Uncovered a range of Boolean functions via automaton dynamics.

Demonstrated input-output mapping using excitation perturbations.

Showed potential for biological computation in actin filament networks.

Abstract

We simulate an actin filament as an automaton network. Every atom takes two or three states and updates its state, in discrete time, depending on a ratio of its neighbours in some selected state. All atoms/automata simultaneously update their states by the same rule. Two state transition rules are considered. In semi-totalistic Game of Life like actin filament automaton atoms take binary states `0' and `1' and update their states depending on a ratio of neighbours in the state `1'. In excitable actin filament automaton atoms take three states: resting, excited and refractory. A resting atom excites if a ratio of its excited neighbours belong to some specified interval; transitions from excited state to refractory state and from refractory state to resting state are unconditional. In computational experiments we implement mappings of 8-bit input string to 8-bit output string via dynamics of perturbation/excitation on actin filament automata. We assign eight domains in an actin filament as I/O ports. To write {\sc True} to a port we perturb/excite a certain percentage of the nodes in the domain corresponding to the port. We read outputs at the ports after some time interval. A port is considered to be in a state {\sc True} if a number of excited nodes in the port's domain exceed a certain threshold. A range of eight-argument Boolean functions is uncovered in a series of computational trials when all possible configurations of eight-elements binary strings were mapped onto excitation outputs of the I/O domains.