# Pathway Projections¶

## Overview¶

PathwayProjections allow information to be passed between mechanisms. A PathwayProjection takes its input from the OutputState of one Mechanism (its sender), and does whatever conversion is needed to transmit that information to the InputState of another Mechanism (its receiver). The primary type of PathwayProjection is a MappingProjection.

## Creating a PathwayProjection¶

A PathwayProjection can be created on its own, by calling the constructor for the desired type of projection. More commonly, however, projections are either specified in the context of creating a State to or from which they project

(see Specifying a Projection, and Projections in State), or are created automatically, as described below.