At birth we possess a brain with the hardwiring that allows for basic sensory and motor function but lacks a complete internal representation of the world. How over a relatively short period of development are our brains initialized to perform rapid decisions based on limited sensory information? Such function is grounded in our abilities to compare an internal representation to ongoing sensory stimuli within the sensory cortex, which is modulated by top-down feedback from higher order brain regions, thus enabling flexible sensory processing. However, whether the establishment of this architecture to perform these functions is present at birth or is assembled postnatally through experience is unknown. My research program aims to determine the developmental contributions of these feedback circuitries in the primary visual cortex and investigate the role of inhibitory interneurons in this process. I also aim to delineate the temporal dynamics of these structural and functional changes and determine how they relate to both mature brain function and synaptic plasticity. We wish to determine how genetic and neurodevelopmental aberrations results in impairment of precise sensory function and modulation. It has been suggested that in schizophrenia, feedback is abnormally strong, leading to phenotypes such as hallucinations, whereas in autism, feedforward sensory inputs dominate, resulting in hypersensitivity. It will be important to elucidate the circuitries that result in these phenotypes.