The laboratory of Dr. Jennifer Morgan studies the cellular and molecular mechanisms by which neurons communicate with each other at synapses, a process called synaptic transmission. We study mechanisms of normal synaptic transmission, as well as how neurotransmission is impacted by spinal cord injury and disease. One ongoing project involves identifying how synapses are deleteriously affected by Parkinson's disease, and we are currently developing strategies to slow or reverse disease-associated synaptic dysfunction. Another project is focused on understanding how neurotransmission can be restored after spinal cord injury by regenerative processes, such as axon and synapse regrowth, or other forms of neural plasticity. Ultimately, we want to understand how these regenerative processes contribute to restoring normal behaviors after injury and how to improve functional outcomes.

For these projects, we use sea lampreys (Petromyzon marinus) as our model organism. Lampreys are cyclostomes, which are the most basal extant group of vertebrates. Lampreys possess a subset of very large neurons that can be identified across animals, the giant reticulospinal (RS) neurons, which provides several advantages for our studies. First, as the name indicates, these RS neurons are giant! They have especially large axons (20-80 microns) and synapses (1-2 microns), which are easily an order of magnitude larger than in most vertebrate models. Second, these giant neurons are experimentally tractable and amenable to molecular manipulations both in the normal and regenerating state. To approach our questions, we utilize a variety of technical approaches including, candidate gene and transcriptome analyses, molecular perturbations, biochemistry, fluorescence imaging, histology, electron microscopy, electrophysiology, and behavior.