Dr. Armstrong’s major research interests at present focus on hippocampal pyramidal and granule cell synaptic plasticity utilizing electro physiological and neurochemical techniques. The lab is using intracellular recording methods to assess the effects of low closes of industrial toxins and endogenous brain peptides on long-term potentiation (LTP) in rat brain tissue slices. LTP is an activity dependent change in synaptic efficacy that is associated with voltage and ligand gated calcium channels. Dr. Armstrong’s long-term goal is to develop the hippocampal slice as a screening device to detect early functional changes in synapses that are associated with neuronal toxicity. The lab has already been successful in identifying subtle changes in pyramidal cell responses that are induced by in vitro application of organotin compounds, such as trimethyltin. These changes in passive and active membrane properties are specific to trimethyltin, a chemical used in the plastics industry that is known to produce lesions in the central nervous system. The observed decreases in input resistance are calcium-dependent and they are continuing their efforts to characterize this effect.