The following figures show the results of the joystick test using the same test line as before. In addition, the flies were fed not only ATR but also 3IY (3-iodo-L-tyrosine), an inhibitor of dopamine synthesis. This was done to determine whether the previously observed effect was due to dopamine alone and could therefore be suppressed by the inhibitor, or whether other factors also influenced the flies’ behaviour in the joystick test.