Rory McQuiston, Ph.D.
Anatomy & Neurobiology
Virginia Commonwealth University
We study an area of the brain crucial to the formation of long term memories – the hippocampus. In particular, we are interested in how small groups of inhibitory neurons (interneurons) influence the integration of excitatory activity in the principal neurons responsible for encoding of information. Currently, the lab is studying the impact of cholinergic and GABAergic inputs from the medial septum and diagonal band of Broca complex (MS/DBB) to an output region of the hippocampus, area CA1, using transgenic and knock-in mice. We also study synaptic responses from the entorhinal cortex on to CA1 neurons. Additionally, we study how pathogenic protein tau, involved in neurodegeneration, may be affecting the function of neurons in the hippocampus. These studies involve investigating the efficacy of synaptic transmission, the impact on different subsets of interneurons, and the downstream network effects on principal pyramidal neuron activity. The lab uses both optogenetics and patch clamp physiology to study these network effects.
We have been and are characterizing MS/DBB cholinergic and GABAergic synaptic inputs onto inhibitory interneurons of hippocampal CA1. We have characterized excitatory postsynaptic nicotinic and muscarinic responses, muscarinic and GABAA-receptor mediated inhibitory postsynaptic potentials, and characterized their synaptic efficacy and the receptor subtypes mediating these responses.
Inhibitory interneurons in hippocampal CA1 consist of multiple diverse subclasses based on their morphology, physiological properties and their synaptic connectivity in the CA1 network. The different interneuron subclasses play different roles in hippocampal network function. Not surprisingly, the various interneurons respond differentially to cholinergic and GABAergic inputs from the MS/DBB. We have been correlating the different morphological interneuron subclasses with specific cholinergic and GABAergic response types.
Inhibitory interneurons ultimately affect synaptic integration, firing probability and rhythmicity in CA1 pyramidal neurons. Therefore, we have been characterizing how the MS/DBB cholinergic and GABAergic inputs affect synaptic inhibition in pyramidal neurons. We have been examining the interneuron subtypes mediating the synaptic inhibition in addition to the patterns of inhibitory responses recorded in downstream CA1 pyramidal neurons.
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Last updated 3/2017