Although growth cone filopodia are very dynamic, our lab as well as others have shown that statistically distinguishable asymmetric distributions of growth cone filopodia are strongly correlated with a turning response in the direction with more filopodia [34] [38].
To define a turning response, we measure the correlation between the turns that the tube makes and the direction toward the micropyle (θ tip and θ mp in Fig. 2C, respectively).
These terms do not assume any particular molecular model for why the pollen tube slows, but their inclusion allowed us to include or exclude either a turning response (Eq. 1) or a slowing response (Eq. 4, in Methods).
For a turning response of A, δθ tip = A sin(θ mp ) δt, such that the total change in the angle θ mp is (2) By this reasoning, the angle θ mp will only decrease (δθ mp < 0) when the response to the gradient A is larger than v/ r.
Although we do not know the identity or function of neurons in rhombomere 2 that receive input primarily from the posterior tectum, we predict that they have a role in executing a behavioral response, perhaps a large horizontal saccade or a turning response, to stimuli behind the animal.
This involves pairing a head turn response to a sound with an interesting visual reward, such as a flashing light or an animated toy animal.
In acetonitrile, a "turn on" response with red emission at 631 nm can be easily recognized, and more than 50-fold enhancement were obtained.
A temporal frequency of 5 s−1 was chosen for the expanding stimulus because it elicits a maximum turning response as measured in a recent behavioral study [22].
Each fly performed eight trials; trials and both sides were averaged to a mean turning response.
When the substrate and C-2 oligonucleotides were labeled with a carboxyfluorescein (FAM) fluorophore and a 4- [4- dimethylamino phenyl]azo benzoic acid (DABCYL) quencher, this SDR catalytic system exhibited a "turn-on" response for ATP.
