Laboratory for Cortical Circuit Plasticity

1. Main theme:Mechanisms of operation and plasticity of neural circuits in visual cortex Project 1Questions: How is each subtype of GABAergic neurons spatially arranged in 3D space of the visual cortex?Are visual response properties different among subtypes?Which subtype of neurons is more modifiable to visual deprivation? Main Methods: In vivo two-photon functional Ca2+ imaging in transgenic mice or rats in which GABAergicor a particular subtype of neurons express fluorescent protein. A, Visual stimulation and in vivo recording of responses of many neurons B, Location of excitatory (blue) and GABAergic (red) neurons in 3D space of visual cortex (left) and visual responses of neurons as indicated (right). Laboratory for Cortical Circuit Plasticity I d e b a C, Identification of Parvalbumin (PV)-, Calretinin (CR)- and Somatostatin (SOM)-positive neurons (left) and clusters of each subtype of neurons (right). c Project 2 Question:Are mechanisms of LTP/LTD different, depending on types of synapses in neural circuits in visual cortex? Main Methods: Dual whole-cell recordings from two cells in visual cortical slices of transgenic mice in which a given type of neurons express fluorescent protein. Green cells, GABAergic interneurons. Different types of synapses show different modes of plasticity. Project 3Question:Does optical stimulation of GABAergic or a given subtype of interneurons modify feature-selective responses of nearby neurons? Main Methods: Optical stimulation of neurons which express channelrhodpsin-2 in GABAergic or subtypes of GABAergic neurons in the visual cortex.