Seminars & Events
Friday, October 4, 2013: Dr. Laurie Ryan, SMCM '86 (National Institute on Aging) will speak on "Alzheimer's Disease: Targets and Treatments" at 3:00 pm in Goodpaster Hall 195.
Monday, October 21, 2013: Dr. Greg Elmer (University of Maryland Baltimore) will speak on "Domains and Constructs in Motivation: Where Does the Habenula Fit In?" at 4:45 pm in Goodpaster Hall 195.
Friday, October 25, 2013: Dr. Terry Davidson (American University) will speak on "Why We Overeat and Become Obese? It Could be What We Think!" at 3:00 pm in Goodpaster Hall 195.
Dr. Gwen Calhoon '06 recently received her Ph.D. in Neuroscience from the University of Maryland Baltimore, and was inducted into Nu Rho Psi.
Gibbons, Kaitlin (2010). Pressure mechanosensory neuron interactions and connections in the leeches Hirudo verbana and Macrobdella decora. Mentor: Dr. Michael Baltzley
The European medicinal leech Hirudo verbana has four mechanosensory pressure neurons (P cells) in each midbody ganglion. Within an isolated ganglion, P cells have complex mutually inhibitory connections. When one P cell is stimulated intracellularly, the other P cells have a weak depolarization followed by a strong hyperpolarization. This complex response appears to be mediated by a combination of electrical coupling, monosynaptic excitation and polysynaptic inhibition. I examined the P cell homologues in the American medicinal leech Macrobdella decora. I found that intracellular stimulation of one P cell causes a slight depolarization in the other P cells. Experiments performed in a high Mg2+, 0 Ca2+ saline and a high Mg2+, high Ca2+ saline suggest that the P cells in M. decora have an electrical coupling, a monosynaptic excitation and polysynaptic inhibition, similar to the connections between P cells in H. verbana. Therefore, the difference in net response between these two species seems to be based on differences in the strengths of the electrical and chemical connections. I also tested the connections between P cells in both M. decora and H. verbana in normal leech saline with bicuculline, a GABA-antagonist. Our preliminary results show that the polysynaptic inhibition was eliminated in both species, suggesting that the inhibition is due to GABA-mediated Cl- channels.