Seminars & Events
Thursday, September 11, 2014: Dr. Bevil Conway (Wellesley College) will speak on his research in visual neuroscience and color at 4:30 pm in Goodpaster Hall 195.
Monday, October 27, 2014: Dr. Todd Gould (University of Maryland Baltimore) will speak on "Genes to behaviors to treatments in bipolar disorder" at 4:45 pm in Goodpaster Hall 195.Friday, December 5, 2014: Dr. Brian Mathur (University of Maryland Baltimore) will speak on "Braking bad: Aberrant inhibitory neurotransmission in addiction" at 3:00 pm in Goodpaster Hall 195.
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.