The Kristina Nielsen Laboratory investigates neural circuits in the visual cortex that are responsible for encoding objects to understand how the visual system performs object recognition. We aim to reveal the fine-scale organization of neural circuits, with an emphasis on higher-level visual areas.
We use two-photon microscopy to perform high-resolution functional imaging of visual areas in the non-human primate. We also investigate how the function of higher visual areas changes over the course of brain development in ferrets, by measuring the activity of single neurons in these areas, as well as determining the animal's visual capabilities at various developmental stages. In both types of investigations, we also rely on detailed anatomical techniques to precisely observe how the function of neuronal circuits is related to their structure.
Research in the Mark Donowitz Lab is primarily focused on the development of drug therapy for diarrheal disorders, intestinal salt absorption and the proteins involved including their regulation, and the use of human enteroids to understand intestinal physiology and pathophysiology. We study two gene families initially recognized by this laboratory: mammalian Na/H exchangers and the subgroup of PDZ domain containing proteins present in the brush border of epithelial cells called NHERF family. A major finding is that NHE3 exists simultaneously in different sized complexes in the brush border, which change separately as part of signal transduction initiated by mimics of the digestive process. Relevance to the human intestine is being pursued using mini-human intestine made from Lgr5+ stems cells made from intestinal biopsies and measuring function via two-photon microscopy.
Researchers in the Nicholas Zachos Lab work to understand variations in protein trafficking that occur during pathophysiological conditions that cause ion and water transport that result in diarrhea. We recently identified a clathrin-independent endocytic pathway responsible for elevated intracellular calcium-mediated inhibition of NHE3 activity in intestinal epithelial cells. We use advanced imaging techniques, including confocal and multi-photon microscopy, to characterize protein trafficking of intestinal transporters. We also perform functional assays using fluorescent probes (ratiometric and non-ratiometric) to measure ion transport in cell culture models, intact intestinal tissues and human small intestinal enteroids.