Pulsed Light Stimulation Increases Boundary Preference and Periodicity of Episodic Motor Activity in Drosophila melanogaster.

Shuang Qiu,R Meldrum Robertson,Chengfeng Xiao

doi:10.1371/journal.pone.0163976

Abstract

There is considerable interest in the therapeutic benefits of long-term sensory stimulation for improving cognitive abilities and motor performance of stroke patients. The rationale is that such stimulation would activate mechanisms of neural plasticity to promote enhanced coordination and associated circuit functions. Experimental approaches to characterize such mechanisms are needed. Drosophila melanogaster is one of the most attractive model organisms to investigate neural mechanisms responsible for stimulation-induced behaviors with its powerful accessibility to genetic analysis. In this study, the effect of chronic sensory stimulation (pulsed light stimulation) on motor activity in w1118 flies was investigated. Flies were exposed to a chronic pulsed light stimulation protocol prior to testing their performance in a standard locomotion assay. Flies responded to pulsed light stimulation with increased boundary preference and travel distance in a circular arena. In addition, pulsed light stimulation increased the power of extracellular electrical activity, leading to the enhancement of periodic electrical activity which was associated with a centrally-generated motor pattern (struggling behavior). In contrast, such periodic events were largely missing in w1118 flies without pulsed light treatment. These data suggest that the sensory stimulation induced a response in motor activity associated with the modifications of electrical activity in the central nervous system (CNS). Finally, without pulsed light treatment, the wild-type genetic background was associated with the occurrence of the periodic activity in wild-type Canton S (CS) flies, and w+ modulated the consistency of periodicity. We conclude that pulsed light stimulation modifies behavioral and electrophysiological activities in w1118 flies. These data provide a foundation for future research on the genetic mechanisms of neural plasticity underlying such behavioral modification.

Highlights

Neuroplasticity is the ability of the brain to adapt to, or to be modified by, environmental stress, injury or trainings [1,2,3,4]
We examined the effects of pulsed light stimulation on w1118 flies at both the level of behavior and the level of electrical activity which was associated with a centrally-generated motor pattern
We report here that w1118 flies generated motor activity in response to the chronic pulsed light stimulation, at the level of behavior with improved boundary preference and increased travel distance in a locomotor assay, and at the level of electrical activity which was associated with a centrally-generated motor pattern showing enhanced periodic electrical/struggling activity

Summary

Introduction

Neuroplasticity is the ability of the brain to adapt to, or to be modified by, environmental stress, injury or trainings [1,2,3,4]. It has been shown that repetitive stimulation has positive effects on motor activity and cognitive abilities in healthy subjects [6,7,8], and patients with chronic stroke [9, 10] or cerebral lesions [11]. The detailed mechanisms underlying the mitigation of brain damage by repetitive stimulation are still elusive. Understanding these mechanisms would consolidate the procedures and their future application in promoting brain recovery

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Conclusion