Experience-dependent Plasticity of the Optomotor Response in Drosophila melanogaster

Abstract

Experience in early life can affect the development of the nervous system. There is now evidence that experience-dependent plasticity exists in adult insects. To uncover the molecular basis of plasticity, an invertebrate model, such as Drosophila melanogaster, is a powerful tool, as many established genetic and molecular methods can be applied. To establish a model system in which behavioral plasticity can be examined, we investigated the optomotor response, a behavior common to most sight-reliant animals, in Drosophila and found that the response could be modified by the level of light during rearing. The angle turned by the head in response to a moving stimulus was used to quantify the response. Deprivation of light increased the response to low-contrast stimuli in wild-type Drosophila at 4 days after eclosion and this plastic change did not appear in rutabaga, a known mutant defective in short-term memory. In addition, the change was transient and was markedly decreased at 6 days after eclosion. Further, we found that Dark-flies, which have been kept in constant darkness for more than 50 years, showed a higher response to low-contrast stimuli even at 6 days after eclosion compared to wild type and this characteristic was not lost in Dark-flies placed in a normal light environment for 2 generations, suggesting that this high response has a hereditary nature. Thus, our model system can be used to examine how the environment affects behaviors.

Noise-robust recognition of wide-field motion direction and the underlying neural mechanisms in Drosophila melanogaster

“…1b , flies turn their heads toward the direction of motion during stimulus presentation. In order to quantify the response, we measured the head yaw angle, which has been established as an index of the OMR 8 . To test the effects of reduced stimulus reliability on wide-field motion processing, we precisely controlled the signal-to-noise ratio (SNR) of the moving stimulus.…”

“…We measured head yaw angle as an indicator of the OMR as described previously 6 . Briefly, cold-anesthetized flies were tethered at the thorax to a steel pin with glue.…”

“…The stripe pattern turned for a duration of 10 s in each CW and CCW direction. The optimal frequency to elicit an OMR in Drosophila is around 4 Hz 6 . In this study, we used 1 and 4 Hz.…”

Dopamine modulates the optomotor response to unreliable visual stimuli in Drosophila melanogaster

“…We measured the head yaw angle as an indicator of the OMR as described previously (Kikuchi et al, 2012;Suzuki et al, 2015). Briefly, cold-anaesthetized flies were tethered at the thorax to a steel pin with glue.…”

“…[Colour figure can be viewed at wileyonlinelibrary.com] shown in Figure 1a, the flies turned their heads towards the direction of motion during the stimulus presentation. To quantify the response, we measured the head yaw angle as an index of the OMR, as described in previous studies (Kikuchi et al, 2012;Suzuki et al, 2015). We controlled the SNR of the motion in the stimulus to test the effects of less reliable stimuli on the perception of wide-field motion.…”