TY - JOUR T1 - AMPA Receptors Exist in Tunable Mobile and Immobile Synaptic Fractions <em>In Vivo</em> JF - eneuro JO - eNeuro DO - 10.1523/ENEURO.0015-21.2021 VL - 8 IS - 3 SP - ENEURO.0015-21.2021 AU - Haiwen Chen AU - Richard H. Roth AU - Elena Lopez-Ortega AU - Han L. Tan AU - Richard L. Huganir Y1 - 2021/05/01 UR - http://www.eneuro.org/content/8/3/ENEURO.0015-21.2021.abstract N2 - AMPA receptor (AMPAR) mobility within synapses has been extensively studied in vitro. However, whether similar mobility properties apply to AMPARs in vivo has yet to be determined. Here, we use two-photon fluorescence recovery after photobleaching (FRAP) to study AMPAR mobility within individual dendritic spines in live animals using an overexpression vector. We demonstrate the existence of mobile and immobile fractions of AMPARs across multiple cortical regions and layers. Additionally, we find that AMPAR mobility can be altered in vivo in response to administration of corticosterone, a condition that mimics exposure to stress. ER -