Only a few more flies compared to the first week, but the difference between optomotor responses after punishing left or right torque, respectively, is starting to show:

These data suggest I should fill the groups up to a sample size beyond 20 if I want to use these data somewhere…

Hello everyone!

Things are not going well…

Over the last week I have encountered numerous problems in carrying out the planned experiment, and the biggest of these is definitely the generation of offspring. Since it has been shown that long-term memory decays quickly in the first 24 hours after operant self-learning on the flight simulator (and with that possible epigenetic marker I suppose), I decided to mate the flies immediately after training and separate them again after 16-20 hours. However, I did not get any offspring by doing this. I tried mating virgin males/virgin females and also adult males/virgin females for 16-20 h, but no eggs could be found in the vials. I have not yet found out what prevents the flies from mating and am now trying again with older (3-4 days old) adult male flies. 

Another problem is the training protocol for memory consolidation by S Xia, L Liu, C Feng et al. 1997. Although I have practiced gluing and inserting flies into the flight simulator, I don’t think I can train enough flies in one day. To maintain sufficient larval density after mating, I need at least 5 females and 2-3 males, and I would need to train them twice, giving a total of 16-18 training rounds per day (and that doesn’t include failed attempts…). Alternatively, I can use the standard protocol and see if the training is enough to reveal epigenetic inheritance of acquired habits, if any. 

For now, I will continue to try to produce offspring and practice gluing and training the flies. I have started to do further research on inheritance mechanisms to see if it might also be possible to work with only the F0 generation and detect epigenetic markers (methylation of genes, e.g. foxP, siRNAs) in the trained flies and compare them with untrained flies. Here (1, 2) you can find a few interesting articles on this topic.  

However there is also some good news to report: my ContonS line will be ready soon, so I don’t have to work with the wtb virgin flies anymore, which decease very quickly. I have also made some progress on the statistical background after talking to a friend of mine although I still need to do some research on how to set my effect size so I can finally calculate the sample size I need for the experiment.

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.

After training 14 flies it looks as if the new setup is working as it should:

Looking at the optomotor traces more closely now that (a) we know that motor neurons are the only site of plasticity and (b) we routinely record optomotor behavior after training, something very interesting appeared when comparing flies that have been trained on one turning direction with flies trained on the other side:

Flies trained to avoid right turning show reduced optomotor response to the right and vice versa! The weaker effect for ‘left’ may be due to the weaker learning in this group?

Anyway, I have never seen this and find it quite exciting!

Hello everyone!

Here is a brief overview of the topics I will be dealing with over the next few months:

This is the experiment by MD Ziv Williams I am trying to imitate ->

• Lamarckian inheritance following sensorimotor training and its neural basis in Drosophila – Williams, 2015

If you are further interested in transgenerational inheritance of behavioral traits and non synaptic memory storage check out these interesting links ->

• Can brain activity transmit transgenerationally? – Miska and Rechavi, 2021
• Is plasticity of synapses the mechanism of long-term memory storage? – Abraham, Jones and Glanzman, 2019

This week, for now, I will continue practicing to glue the flies and make a realistic estimate of the number of flies I need to get a significant result. Hopefully I can start trying out my experimental setup by the start of next week :)

The old software is installed with the new hardware and I’ll be testing the new software in parallel to experiments with the old software. Technically, everything seems to be working now, but the first six flies I tested did not show learning after training:

However, avoidance looks fairly ok, only the last training period gives away that something still isn’t quite the way it should be:

So I’ll go ahead and train a new batch of flies this week. I’ll focus on training/avoidance and make sure it is perfect, before I shorten the training.

MB417B -> α’/β’ap, α’/β’m, α/βs, α/βp
MB463B -> α’/β’ap
MB371B -> α/βp