RecruitingSocial Disconnection StudyThe purpose of this research study is to examine the effect of social connectedness on the brain. Study procedures include one Magnetic Resonance Imaging (MRI) or functional Magnetic Resonance Imaging (fMRI) scan, one Positron Emission Tomography (PET) scan, one Magnetic Resonance Spectroscopy (MRS) scan, an electroencephalogram (EEG), and in-person and phone call follow-ups.