The English lab is interested in understanding the physiology of neural circuits in the hippocampus, which facilitate systems level functions including memory and neural representation of space and time. A primary question the lab is interested in is how cell assemblies are constructed and maintained. Cell assemblies are groups of neurons which come together in time to robustly represent cognitive and behavioral features.
All of our experiments are performed in awake behaving mice, to enable us to directly test physiological circuit function in the intact, behaving, brain. We utilize wild-type and transgenic mice engineered to express light-modulated ion channels/pumps (opsins), which enable us to monitor and manipulate the activity of genetically defined neuronal populations in awake behaving animals. To monitor neural activity we use extracellular, juxtacellular and intracellular recording methods. Extracellular recording with high-channel count silicon recording probes enable us to study the spiking activity of large neuronal ensembles (~hundreds of single neurons). Juxtacellular recording with glass electrodes enable us to monitor and manipulate the spiking activity of single neurons, and to dye-load these cells enabling post-hoc morphological investigation. Intracellular recordings allow us to monitor (and manipulate) the intracellular membrane potential of single neurons which provides access to the synaptic inputs to single neurons and the dynamics of single cell excitability. The multiplexed application of these techniques enables us to test targeted hypothesis in the intact, functioning brain.