The Flight Simulator
Here it is in action

This image shows the entire setup as viewed from the front. The room was darkened for the experiment. For more picture click here.

 This image shows the output of the video card (see below) with a time synched inset of a moth during closed-loop "flight". Click here for an example.
Here's how it works
The 3-D environment is created using the computer flight simulator game Descent III. I modified the environment using a downloaded editor. The environment is sent through an LCD projector and projected onto a rear projection dome screen created by the Flogiston Corporation. A tethered moth (or any other insect) is placed close to the apex of the dome and an overhead camera is used to monitor wing and body kinematics. The abdomen position sensor monitors abdominal ruddering and reports a voltage to the feedback system (see below) used to control the visual environment, thus closing the loop. A curved glass tube provides a channel for the wind source and an odour cartridge is used to inject odours of interest into the air stream. Multichannel probes (see inset below) are used to record multineuronal activity during "flight". The output of the video card is recorded for offline measurement of environmental parameters. A second computer is used to run a network "game" to provide an overhead view of the arena and thus record the virtual flight track during an experiment.
Here is a close up view of the area outlined in the image above showing the relative positions of the tethered moth, the wind source, the abdomen position sensor and the multichannel silicon microprobes. These probes were provided by the University of Michigan Center for Neural Communication Technology.
The feedback system
Essentially, the feedback system uses the voltage output of the abdomen position sensor to emulate the signals provided by a joystick. The joystick interface circuit (see circuit diagram below) incorporates controls to adjust gains for all degrees of freedom which are used for the initial calibration at the start of an experiment. The circuit also accepts input from a joystick and thus the system can operate in open or closed-loop conditions. The output of the circuit can also be fed into a data acquisition system and thus allow the abdomen position or joystick signal to be synchronized with the multineuronal recordings.
The joystick feedback circuit
This circuit was created by Vincent Pawlowski (ARLDN, University of Arizona). It was based on a simpler circuit created by Tomi Engdahl, which is available by clicking here.