Spatial organization of synaptic plasticity in cerebellar parallel fiber : Purkinje cell synapses.
Zhou, Ariyo Mitriya Wenyong.
Date of Issue2009
Duke-NUS Medical School
Not much is known about spatial patterns of Parallel fiber-Purkinje cell long-term depression (PF-PC LTD). For this reason, I visualized the distribution of PF-PC LTD in relation to the area of conjunctive stimulation by using voltage-sensitive dye imaging. During stimulation, the basic optical response was observed to have an early “spiky” component and a slower trailing component. Following a 1 Hz train of stimuli, LTD was induced and could be visualized as a decrease in the response elicited by subsequent stimuli. Such LTD was restricted to the molecular layer of the cerebellum, consistent with a decrease in transmission at the PF-PC synapse. Ratio imaging allowed me to further characterize the spatial range of LTD. Line scan analysis revealed that the amount of LTD generally decreased with distance from the stimulation site, demonstrating a gradient limited by the distribution of activated PF synapses. In addition, LTD extended for 80 μm further than the peak area of PF activation, consistent with previously indications of the spread of LTD beyond active PF synapses. I conclude that LTD spread is likely to be limited by 2 things: (1) the distribution of activated PF synapses; and (2) the spread of chemical signals generated during LTD.
Final Year Project (FYP)
Nanyang Technological University