2008 Brain Star Award Recipient - Susan Rai
Recipient
Susan Rai - Biosketch
Master of Arts (Psychology)
University of British Columbia
Article
Rai, S., & Rankin, C. (2007). Critical and Sensitive Periods for Reversing the Effects of Mechanosensory Deprivation on Behavior, Nervous System, and Development in Caenorhabditis Elegans. Developmental Neurobiology. 67 (11), 1443-1456.
Significance of the paper
Varying amounts of mechanosensory or touch stimulation during development can drastically alter the structure and function of the nervous system. Some of these effects must occur during specific stages (critical periods) of growth for normal development to occur. Because of its rapid lifecycle and lack of maternal nurturing, C. elegans is used as a model system for investigating development in isolated versus deprived conditions. Rose et al. (J Neurosci 2005; 25:7159–7168) showed that a lack of mechanosensory stimulation during development leads to a decreased motor response in adult worms, significantly smaller body size, and significantly lower levels of both a postsynaptic glutamate receptor (GLR-1) and a presynaptic vesicle marker (SNB-1) in the tap sensory neurons. In this study, brief mechanical stimulation at any time throughout development reversed the effects of isolation on behavior and on postsynaptic glutamate receptor expression, suggesting there is no critical period for these two measures. In contrast, only low levels of stimulation rescued vesicle expression in the tap sensory neurons early in development. Progressively higher levels of stimulation were required as the worm developed, suggesting a sensitive period immediately after hatching, followed by a period of decreasing plasticity. Lastly, stimulation during the first three stages of larval development, but not later, rescued the effects of isolation on worm length, suggesting there is a critical period for reversing body size that ends in the third larval stage. Overall, these results indicate that different aspects of the nervous system require varying amounts and/or timing of stimulation to reverse the effects of early deprivation. As we identify critical periods of plasticity during development we can further our understanding of the relationship between experience, genetics and behavior, and continue to develop our understanding of brain development and plasticity.