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.

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.