Joystick Results for 2-minute-testing

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.

Red light Joystick Results

Yellow light Joystick Results

Update: Red light Joystick results

After the first full week of testing the three different fly lines with red light, we have analyzed the results. We are now able to provide a further update on our findings.

While the effect for the control groups seems to stay consistent with our previous findings, the effect for the positive control has weakened and is closer to the strength measured in previous experiments. We utilized the norpAP24;Gr28bd+TrpA1>Chrimson line for both our positive and negative controls.

Furthermore, the experimental group, which previously favored red light in the post-test, showed a more varied and inconclusive profile. We will need to conduct further testing to determine whether the previously observed effect was simply caused by the small sample size.

Another important discovery was the necessity of feeding the flies sugar water 5-10 minutes before the experiment in order to maintain their activity levels. This way the flies will be identified as a valid data point by the R-script and will ensure more and more accurate data. It is important to note that we will implement this feeding process in all future experiments to ensure consistency and accuracy of the data collected.

Red light Joystick Results

Aslıhan Enes Red Light T-Maze Results

Results for Red Light T-Maze experiments.

Aslıhan Enes Yellow Light T-Maze Results

Results for Yellow Light T-Maze experiments.

Positive controls in joystick optogenetics

I’ve started rescreening Christian’s most consistent dopaminergic lines with the positive controls at the joystick machine, to see if everything works. These flies express the optogenetic channel Chrimson in Gr28bd and TrpA1 heat sensitive neurons, so they should use the joystick to switch the light off.

I tested three rounds of three flies each and I got the impression that it worked while I was looking at the flies. The data didn’t look that great, however:

Setting up the experiments, I noticed that the middle setup didn’t really focus the light on the head of the fly very well. This shows in the raw performance index data:

The two middle flies (row #2 and #8) have positive preferences, but never avoid the light, while nearly all other flies do avoid the light to various extents, even if they start out with a positive preference. So I deleted these two flies to see how the data would look then:

I decided that this should be good enough. I improved the middle setup to focus the light better on the fly’s head. Hopefully it will improve the PIs of the flies placed there now.

FENS poster (link for students)

Role of dopaminergic neurons in operant behaviour

Positive Control: Gr28bd-G4, TrpA1-G4

Parameters: Light: intensity (500 Lux side, 1000 Lux bottom); frequency = 20Hz; Delay = 1 ms; Duration = 9.9 ms; volts = 6.4

Red lines: completed

mb025b: not selected against tubby