Björn BrembsView Profile
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!
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.
If you missed it at the Göttingen NWG meeting, you can download our poster from here:
Last week, high-school student Marie Grünleitner tested wild type and blind flies in a modified Buridan’s paradigm. Instead of just two stripes, she put four stripes onto the arena walls: one stripe on one side and three stripes on the other. This experiment was inspired by a poster at FENS22 which is summarized in this preprint. She tested 15 flies in each group. She found that wild type flies prefer the threes stripes (up in the figures) while blind flies stay mostly anywhere at the edge of the platform.
Wild type flies:
NorpA blind flies:
I will use the other software from the authors in Paris to see if it runs on our data and what results these evaluations will yield.
At the beginning of last week, the flies in the optogenetics rescreen seemed to behave very different compared to all the weeks before: groups that kept the lights on now switched it off and vice versa. There was also some of that in the control flies, but to a lesser extent. This is what the last training PIs looked like for the seven groups before last week:
The data from last week then looked like this:
Especially the two groups that did receive ATR reversed their previous screen results. Potentially, reduced concentration of ATR may have reduced the effect of light which may have led to the reversal of the effects.
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.
We are looking for a PhD student for behavioral experiments with Drosophila fruit flies with manipulated FoxP function.
The human orthologues of the fly FoxP gene are the FOXP1-4 genes. Mutations in the FOXP2 gene cause verbal dyspraxia, a form of articulation impairment. Humans learn to articulate phonemes and words by a form of motor learning we can model in flies. Supporting the conceptual analogy of motor learning in humans and flies, manipulations of the fly FoxP gene also lead to impairments in motor learning.
In the past year, graduate student Ottavia Palazzo used CRISPR/Cas9 to edit the FoxP gene locus, tagging the gene with reporters. These reporters allow us to manipulate not only the gene, but also the neurons which express FoxP. The candidate will work closely with Ottavia to design behavioral experiments characterizing the various manipulations of the different neuronal populations for their involvement in the form of motor learning we use, operant self-learning at the torque meter:
The position is fully funded by a grant from the German funding agency DFG, with full healthcare, unemployment, etc. benefits. It includes admission and tuition to the “Regensburg International Graduate School of Life Sciences“. Starting date is as soon as convenient.
The successful candidate will have a Master’s degree or equivalent. They will be proficient in English as our group is composed of international members. The ideal candidate will have some training in behavioral experiments in Drosophila or other animals, some coding experience and an inclination towards electronics. However, all of these skills can also be learned during the project.
We are a small, international group consisting of a PI (Björn Brembs), a postdoc (Anders Eriksson), one more graduate student besides Ottavia (Christian Rohrsen) and a technician. We are an open science laboratory and so one aspect of the project will involve a new open science initiative in our laboratory, where we have developed a simple method to make our behavioral data openly accessible automatically, i.e., without any additional efforts by the experimenter. This entails at least two advantages for the candidate in addition to doing science right: the data are automatically backed up and there is no need for a data management plan.
Regensburg is a university town in Bavaria, Germany with about 120k inhabitants and a vibrant student life, due to the 20k students enrolled here. The University of Regensburg is an equal opportunity employer.
Interested candidates should contact Björn Brembs with a CV and a brief letter of motivation.
Lena Matzeder just finished her Bachelor thesis, entitled “Is anxiety a factor influencing photo-preference in Drosophila melanogaster?“. She administered Diazepam (valium) to flies and asked them if that changed their preference for bright or dark places. A warm welcome to Weitian Sun, a Master’s student who will be testing candidate genes for their involvement in operant self-learning.