Editing keys can be done from a configuration file:

* Browse to your Steam installation directory,
* From there, go to SteamApps/Common/Mind_Path_to_Thalamus/Mind_Pathtothalamus/Config
* Edit file DefaultInput.ini with a plain-text editor (e.g., notepad).

Directions are handled along positive and negative directions toward an axis.

To edit forward/backward keys, you'll have to find the line begenning with:
Beware! A very similar line is
Choose the lines beginning with a + sign.
There should be a few of them: at least two keys, each two directions.

To edit sideways directions, you'll have to find lines beginning with:

The direction is indicated by:
Its sign indicates the actual direction: 1 is positive toward axis, -1 is negative.

Moving backward is MoveForward with a scale of -1.
Moving left is MoveRight with a scale of -1.

Replace this item in the line, choosing the key you want:

E.g.:
can become
if you want to remap the W key to Z for forward moving.