Depends on the following packages to be included in the main file.
\usepackage{tikz}
\usepackage{xcolor}
\usetikzlibrary{matrix,chains,positioning,decorations.pathreplacing,arrows,shapes.gates.logic.US,shapes.gates.logic.IEC,calc}
E.g. of usage:
\begin{figure}[ht!]
\centering
\hbox{\hspace{5em}\input{PATH_TO_HTMNeuron}}
\caption{Caption}
\label{fig:HTMNeuron}
\end{figure}
