In the McQuiston laboratory, 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) control the integration of excitatory activity in the principal neurons that encode information in the hippocampus. More specifically, we are interested in how the release of the neuromodulator acetylcholine and the neurotransmitter GABA changes hippocampal neural network function, as occurs during attentive behaviors. In our investigations, we use optogenetics to control selective groups of neurons and measure changes in single cells and hippocampal network activity using whole cell patch clamping and voltage-sensitive dye imaging. Cre mice are used that allow the expression of light-activated optogenetic proteins in selective subtypes of local and projection neurons. The techniques involved in these studies include AAV design and production, stereotaxic mouse surgery, genotyping, immunofluorescence and confocal imaging. We hope that our studies will contribute to a better understanding of both physiological and pathophysiological changes that occur in hippocampal neural network function.