• The review on screening proprioceptors relevant for self-learning in D. melanogaster
  • Hasti Saharkhiz,1,* Parva Nasimi,2
    1. Non-governmental Setaregan ِِِِِDerakhshan high school, Department of Education, District 4, Ahvaz, Iran
    2. Imam Jafar Sadegh Research Center, Department of Education, District 4, Ahvaz, Iran


  • Introduction: Adult Drosophila has got three peripheral mechanoreceptor organs include: hair plates, campaniform sensilla and chordotonal organs which serve proprioceptive functions. Besides them, bristle as a fourth mechanoreceptor organ acts as a touch receptor, but it also may receive the proprioceptive stimuli. Modulating the activity of these specific sensory neurons (proprioceptors) with temporal precision in behaving flies combined with in vivo monitoring of neural activity can led to a understanding of the action of proprioception through reward or punishment associated self-learning in the Drosophila. There are various effector transgenes which are able to test neuronal activities based on calcium concentration, synaptic vesicle fusion, CAMP level or voltage with changes in fluorescence. Scientists can use these reporters to demonstrate the extent of the activity of proprioceptors through self-learning. In the present research, we aim to investigate different proprioceptory organs to study the different roles of these neurons during self-learning. We showed whether the neurons of theses organs (hair plates, campaniform sensilla and chordotonal organs) play any roles through self-learning or not.
  • Methods: We reviewed the publications on the relation between stimulating proprioceptors and Drosophila self-learning mediated behaviors.
  • Results: As described by different published articles, we can use flight simulators to test self-learning in normal and adult Drosophila. Flight stimulator is a wonderful method to detect visual operant learning as well as other types of operant learning. In this method, a tethered Drosophila learns to choose one of two patters to avoid heat punishment, because only one of the patterns is coupled with heat punishment. These patterns can be upright and inverted T -shaped patterns for “elevation” or other patterns for “contour orientation”, “size”, “vertical compactness,” and “color”. For example, we can combine a color (blue or green) with an electric shock as punishment or some sugar as reward to test self-learning. This model can be combined with transgenic tools which can inhibit the activity of specific proprioceptor or even proprioceptory-associated ascending neurons. Variant neurotransmitters, receptors, and ion channels can be blocked or excited in order to analyze the function of proprioceptors through self-learning test (such as yaw torque learning assay).
  • Conclusion: Transient Receptor Potential (TRP) cation channels are expressed in different sensory neurons as well as in proprioception. The blocking or exciting gated ion channel as an effective component of senses including proprioception can affect self-learning. Modulating these channels shows the significant aspects of self-learning that are mediated by proprioceptors. There is specific intersegmental neurons hyperpolarization following optogenetic stimulation of leg chordotonal neurons assess the functional consequences of proprioceptive stimulation during self-learning. The inhibitions of proprioceptors in chordotonal neurons indicate the role of proprioception in suppress excitatory touch signals in the vivo model of Drosophila. Some pieces of evidence suggest that dopaminergic neurons in brain and ventral nerve cord may participate in mechanosensory habituation. Dopamine signaling via type-1 and type-2 dopamine receptors has been shown to typically mediate learning in flies through a cAMP-dependent protein kinase pathway and locomotor activity, respectively. This result discovered the primary stages of somatosensory integration in Drosophila using in vivo recordings from genetically labeled central neurons in combination with mechanical and optogenetic stimulation of specific proprioceptors through self-learning experiments. Thus, the recent studies using the medical neurogenetic assays have shown the importance of proprioceptive neurons through Drosophila self-learning.
  • Keywords: Drosophila melanogaster, self-learning, proprioceptors, medical neurogenetic, mutant.