Brian Christie: Research Interests

Research Interests

I can best be described as a systems neuroscientist, and my research is primarily directed towards understanding the cellular and molecular mechanisms involved in learning and memory in the mammalian brain. The majority of my work is done in the hippocampus, an area of the brain that is known to play an important role in learning and memory in humans and sub-mammalian species. One of my primary interests is long-term synaptic depression (LTD) and it's counterpart, long-term potentiation (LTP). Using in vivo extracellular recordings, in vitro whole cell recordings, and fluorescence imaging, we have been studying the cellular mechanisms involved in the induction of these forms of synaptic plasticity in the hippocampal formation of rats. A major finding from this research has been that the prior history of activity in a neural pathway can regulate the subsequent induction of synaptic plasticity in that path. This phenomena has recently been termed "metaplasticity", and may offer significant insight into the functional role of neuromodulatory substances in learning and memory. A second area of interest is the role of calcium in these processes, and especially the role of voltage activated calcium channels. These channels provide the majority of the calcium influx into active neurons, and we have shown them to play a role in both LTD and LTP in the hippocampal formation. Finally, we are also investigating the role of interneurons in information processing at the systems levels. These inhibitory cells are quite morphologically diverse, and strategically placed to gate information transfer in the hippocampal formation. Furthermore, distinct subclasses of these cells have specific termination patterns onto either excitatory hippocampal cells or other interneurons and thus offer a means by which synaptic signaling can be subtly directed. Although these cells may play an important role in information processing, the physiology of these neurons, and the effects of most neuromodulators on these cells is not well studied.

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