Now that we have established that the plasticity underlying self-learning is located somewhere in the steering motor neurons of the ventral nerve cord, the next question is: which of the neurons are involved. To this end I have now started to knock-out aPKC in either B1 neurons or in B3 neurons. The muscles innervated by these motor neurons are an agonist/antagonist pair and serve to advance/delay the turning point of the wing, leading to a larger or smaller, respectively, wing stroke amplitude. Asymmetry in the activity of these neurons leads to yaw torque – which is the behavior we condition. In the first two weeks, I noticed that all three groups (B1- knock-out, B3 knock-out and genetic controls) seem to fly reasonably well. So far, it doesn’t seem like there are any striking differences between the lines, but it is still early days and about three times more animals are needed before one can draw any firm conclusions:

For all experiments 30 or more flies were introduced to the T-Maze.

Results for red light

Results for yellow light

Results for red light

Results for yellow light

I tested more wtb, this time with the switch mode protocol. Here are the results:

Slowly the data are filling up and we start to see some differences emerge between the controls and the aPKC knock-outs:

We still need to get to about N=40, so there is still some way to go.

Going over the optomotor responses with a fine comb revealed a bunch of flies where the algorithm wasn’t able to provide a proper fit for the OMR asymptote. Therefore, I will need more time to finish the data set. Here the current torque-learning PIs:

Clearly, the genetic controls learn while the flies with knocked-out aPKC in FoxP neurons fail to show a significant learning score. However, the OMR asymmetry effect in the genetic controls appears weaker than the one we discovered in WTB flies, as can be seen in the OMR traces after the self-learning:

Then again, at the .05 level, the asymmetry index is significant. Not the alpha level we commonly use, but also a lower N than we strive for (above is before training, below is after):

The transgenic experimental flies, in contrast, don’t seem to show much of an effect at all:

Not many fliers left now. Will start evaluating optomotor asymmetry now.