Our research takes a bottom-up approach to understanding how the neural circuits of this massively interconnected network of neurons are functionally organized and how dysfunction in these circuits contributes to neurodegenerative diseases like amyotrophic lateral sclerosis and neuropsychiatric disorders including autism and schizophrenia.  Approaches We use a variety of techniques to address these questions including: 1. Whole-cell patch clamp recording from multiple neurons simultaneously in brain slices to determine the organization of neural circuits and their synaptic properties. 2. Optogenetic approaches to stimulate or inhibit select classes of neurons and interrogate the function of neural circuits. 3. Transgenic mouse lines to control the expression of desired proteins in subsets of neurons. 4. Viral constructs to target protein expression to specific subsets of neurons, 5. single cell RNA sequencing technologies, allowing us to determine the anatomical relationship among cell types and to probe the functional properties of their connections.