Professor Gradinaru's work has focused on developing and using optogenetics (Gradinaru et al., Cell, 2010) and tissue clearing (Chung et al., Nature, 2013; Yang et al., Cell, 2014; Treweek et al., Nat.Prot, 2015) to dissect the circuitry underlying neurological disorders such as Parkinson's (Gradinaru et al., Science, 2009). Her group is now working to understand how perturbations of neuronal network activity can permanently impact the function and even viability of comprising neurons and ultimately change network properties and animal behavior. Of particular interest to the Gradinaru laboratory are chronic experiences, subtle but persistent actions on brain networks that can cause lasting changes in the structure and function of individual cells and circuits. Research on these topics has been complicated by the heterogeneous nature of the brain. Professor Gradinaru previously helped develop optical modulators of brain activity and the ability to target them to defined pathways as well as the methods necessary to monitor the influence of such manipulations. The Gradinaru laboratory will continue to develop and disseminate enabling technologies (including delivery vectors; Deverman et al, Nat.Biotech., 2016) for high content anatomical mapping and chronic bidirectional control to define circuit changes that affect cell function and health and to understand the fundamental mechanisms behind such changes.