Optical access to auditory cortex for use in in-vivo two-photon calcium imaging

Abstract

In-vivo two-photon calcium imaging is a powerful tool that enables us to measure the activity of hundreds of individual neurons simultaneously. To better understand how the brain processes sounds, we will use this imaging technique to measure the activity of neurons in the auditory cortex when an awake mouse is presented with changes in sounds. To image activity at the neuronal level, optical access is achieved via implantation of a cranial window. However, the auditory cortex is not easily accessible during surgery due its lateral location and large muscles and arteries around the ears. Here, we report an updated protocol for cranial window implantation over the auditory cortex for use in in-vivo two-photon calcium imaging. With optical access to the auditory cortex, we are able to use in-vivo two-photon calcium imaging to evaluate sound-evoked responses of hundreds of auditory cortical neurons. This data will allow us to classify and map the locations of neurons in the auditory cortex that are responsible for processing changes in sound.