Our lab is interested in understanding the mechanisms underlying circuit assembly in developing sensory systems. Of particular interest to us is how inputs of multisensory origin converge at the level of the midbrain and segregate into distinct processing streams. The inferior colliculus (IC) is a strategically situated midbrain relay hub that receives a rich array of both bottom-up and top-down connections. In aspects of its shell nuclei (namely the lateral cortex of the IC, LCIC) multimodal afferents initially intermingle early in development, and later segregate into functional zones that align with the emerging characteristic modular-extramodular LCIC framework. Somatosensory inputs preferentially target developing modules, while inputs of auditory origin terminate in encompassing extramodular regions. Currently we have multiple ongoing projects in the lab examining the mechanisms important for shaping these discrete multimodal maps during early critical periods. Understanding the events necessary for appropriate targeting and refinement of developing sensory circuits should help to guide future interventions for those that suffer from a variety of neurodevelopmental conditions, including autism spectrum and sensory processing disorders.
Molecular guidance mechanisms and glial-neuronal interactions are both vital for the establishment and shaping of similarly organized neural maps in other systems. One focus of our lab is determining the role that a large family of receptor tyrosine kinases and their corresponding ligands, the Eph-ephrins, play in instructing an initial blueprint of connections prior to systems coming online. Another emphasis involves the resident macrophage of the CNS, the microglial cell, and understanding its roles in defining the LCIC microarchitecture and selective pruning of exuberant synapses. To address these and other questions we utilize a combination of neuroanatomical, (tract-tracing, immunohistochemistry), physiological (auditory brainstem responses), and behavioral (pre-pulse inhibition of the acoustic startle response) approaches in a variety of control and transgenic lines. Advanced microscopy (epifluorescence, confocal, etc) and 3-D reconstruction applications are used to visualize and better understand the emergence of neural maps that underlie many of our reflexive and orientation behaviors.