Major and Classification
- Albert Herrera, Ph.D.
Using DiI to Label Motor Axons in Embrionic Developmental States of Xenopus Laevis
Experiments on learning and memory acquisition in human beings have confirmed the importance of experience as a critical modulator of synaptic circuitry. Neuromuscular junctions (NMJs) of frogs are very essential to study the anatomical changes involving synapses, since synapses at NMJs are easy to access and observe. In the embryonic stage of the frog Xenopus laevis, the pectoralis muscle fibers are polyneuronally innervated by motor axons from multiple inputs of motoneurons. This polyinnervation of muscle fibers significantly decreases and at the adult stage of development the muscle fibers comes to only be innervated by one motoneuron, or the muscle is said to be mononeuronally innervated. The decrease in synaptic connections from the embryonic to the adult stage of development is due to phenomena known as “synapse disassembly” and “input elimination”. The aim of this experiment is to determine at what developmental stages of Xeopus’s pectoral muscle synapse elimination or disassembly occur. Understanding the time period at what stages of development synapse elimination occurs paves the way to design methods to study the mechanisms that govern the phenomenon. Based on pervious studies on the pectoralis muscle that are however inadequate to make any significant conclusion, synapse elimination is believed to occur between stages of 61-63 of development of Xenopus laevis.