Calibration(of different units of intensity) for Tmaze and Joystick platform

on Wednesday, June 13th, 2018 12:38 | by

  1. For the Joystick experiment – We continuously varied the light intensity at the tip of the optical fibre and measured it using the Lux meter at first and then in mW/cm^2. Then both these readings were taken down and the best fit was generated which depicted the measured fit. Now a theoretical fit was also generated and plotted. This is given below
  2. We also did the best fit for the Tmaze experimental setup. We measured the light intensity on both sides of the chamber in between and took the average of it. 
  3. The Information for plotting the theoretical fit was obtained from here:

    ## 1 Watt = 517.031 lm at 590 nm

    ## 1 lux = 1 lm/m2

    ## Therefore: 517.031 lux = 517.031 lm/m2 = 1 Watt/m2 = 1000mW/mm2 = 10mW/cm2

    Light Measurement Handbook: Measurement Geometries

Best intensity of light for crimson channel in Joystick experiment

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Used positive control flies (NorpA; UAS Crimson) to check what intensity of light is better for activating the crimson channel and for studying learning behaviour in the joystick experiment.  Tested light in 3 intensity ranges to check what would be best suited.

  1. Initially, we were doing experiments at 700 lux intensity. We saw results which possibly point out to damaging of neuronal populations due to such high-intensity light. As can be seen in the graph below, there is a strong aversion in the first 2 minutes of the training period. However, this aversion drastically decreases later and a very strong phenotype is not shown later. This may prove the hypothesis that high-intensity light(about 700 lux) may result in damage to neuronal populations.
  2. So we tried with two more light intensities – 400 lux and 100 lux. The graphs for these are attached below. As can be clearly seen that now the results dont just show up for the first training segment but remain til the very end. This indicates that both 100lux and 400 lux light intensity are safe and do not disrupt neurons. Also, it can be clearly seen that there is a stronger and more pronounced effect with 400 lux light intensity. Thus we decide that 400 lux light intensity needs to be used for testing crimson channel expression for the joystick experiment.