Isolated operant component in the flight simulator

on Monday, January 21st, 2019 2:43 | by

Isolating operant component removes preference for left and right turning.

Each period is set to 120 seconds, meaning that the flies are getting a total of 8 minutes of training. The flies are performing two initial pre-tests, one test after 4 minutes of training and two final test periods. For the entire duration of the experiments flies are given a color indication if they are being punished or not as a result of left or right turning, this is a composite learning control. For the final test periods the colors have been removed, meaning that we are isolating the operant component. This is different from the previous tests that has been done where flies were not challenged with colors but just relied on their own behavior to determine which side is being punished. A removal of the helping colors resulted in a lack of preference for left- or right-turning maneuvers.

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Come work with us on FoxP!

on Wednesday, December 19th, 2018 2:52 | by

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.

FoxP isoform B expression pattern in the adult brain (green). Counterstaining: Bruchpilot (red)

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.

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Measuring transmission spectra of color filters

on Monday, December 17th, 2018 1:32 | by

Measured with two different light sources. 

Dissection light

Light in torque meter

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17d flight simulator

on Monday, October 1st, 2018 2:58 | by

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17d

on Monday, September 10th, 2018 1:03 | by

Been working on 17d for the past month.

The experiments in the flight simulator. Self-learning performance indices in a two-minute test with the heat switched off after 4 and 8 minutes of training, indicated impairment of 17d-TNT flies.

The flies also showed clear impairments in their flight performance. To quantify this I assessed both possible alterations in their motor coordination (using climbing assay) as well as flight performance. The climbing assay relies on walking rather than flying. Both experiments show reduced ability of motor coordination and flight performance.

 

 

To confirm the specificity of the 17d-Gal4 fly I used the trans-tango flies.

Neuron, 96 (2017) 783-799. doi:10.1016/j.neuron.2017.10.011

 

The trans-tango is notorious for having a low expression in adult flies, which was also observed by me. The image is taking without any GFP-antibody.

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Fussl shows numerical difference in operant self learning

on Tuesday, August 7th, 2018 2:49 | by

Fussl was crossed with either Stinger (ctrl) or a UAS-TNT line to block the synaptric transmission of the Fussl positive neurons. A third construct was used but did not yield any data due to difficulties with their flight performance. The Fussl-Stinger along with Fussl-TNT flies do also show difficulties in flying. These differences will be assessed.

The experiment was done as a pilot experiment before doing a larger scale.

The data is a bit inconsistent but shows a positive and reassuring numerical difference. The control is a bit lower than expected, compared to WTB flies (showing usually a PI 0f 0.6). The flies have a slightly different background than wtb flies and have pale orange eyes (still no apparent impairments in vision). Further experiments will be conducted before proceeding with a larger sample size of the flies.

 

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Joystick Update

on Monday, July 30th, 2018 2:08 | by

Assessing the difficulties in self-learning for FoxP flies

on | by

FoxP3955 flies were raised and compared to normal WTB flies. Reportedly, the Foxp mutants have a reduced flight performance as their total flight duration is decreased. This was also something I experienced. The problem seemed to be greater due to the heat in the flight simulator room, initial temperature was 27°C but increased to close to 30°C. I had troubles getting a large sample size enough (same number of Foxp and wtb were loaded into the flight simulator), heat-shock proteins and other stress-related behavior might be an issue. The genotype of the flies were known during the hooking of the flies but was later on concelead and flies were randomly distributed.  

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Role of dopaminergic neurons in operant behaviour

on Friday, July 27th, 2018 3:54 | by

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

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Mean trace of all flies and how degrees of freedom vary over learning

on Monday, July 23rd, 2018 6:40 | by

Mean trace of the positive control in the Joystick to get to see what are the overall dynamics and maybe to get an idea what might be the best score to pick.Here the standard deviation of the flies along the time axis. This is just to see if all the flies have more similar phenotypes with each other or not at each time.

This is to see if the flies have less degrees of freedom at any segment by measuring the standard deviation at each segment. There does not seem to be any effect. Although this might be mixed with the wiggle scores. I think measuring entropy is a better measure.

 

All the same plots as above but for TH-D’, the interesting line from the screen.

 

Standard deviation across flies

Standard deviation across segments

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