The goal for this study is to compare performance between a conventional helium based "Cryo_MEG" (magnetoencephalography) system and an investigational optically pumped ('OP_MEG') MEG system using brain recordings from typically developing adults. MEG (magnetoencephalography) is a safe, non-invasive brain imaging method used in many forms of research as well as clinical care. MEG is measured by safely wearing a helmet filled with MEG sensors. During the MEG scan, you will be asked to look at a screen, listen to some tones, and push a button. OPM (Optically Pumped Magnetometry), is a brain imaging method that is also worn as a helmet and acquires MEG recording data but differs from conventional "cryo-MEG" because OPM sensors can be positioned closer to the head. This may present an opportunity for better measurement of underlying brain activity.

Patients with who have had Fontan surgery are at risk for the development of liver fibrosis and cirrhosis. New MRI based imaging techniques allow for non-invasive assessment of liver stiffness and fibrosis. These methods have been used in other diseases, but have not been studied in those who have undergone the Fontan operation. In this study we will test the feasibility of MRI based methods for the assessment of liver disease, and compare the results of these studies to those obtained from clinical liver biopsy.

HIV infection can cause harm to the brain and negatively affect memory, learning, and decision making in daily activities. Smoking may affect the ability of medications to reduce HIV in the bloodstream (viral load), which may affect long-term survival and brain health. This study will look for changes in the brain that might have occurred due to HIV infection or smoking.

We want to study brain responses during simulated driving and are currently looking for participants 12-17 years old or those who have had brain surgery. To do so, we'll have eligible participants come to CHOP for some non-invasive (safe) brain scans and drive using a simulator. If you are interested in learning more about the study, please contact Victoria Kaufman at kaufmanv@chop.edu or 267-425-4150.