Auditory System: Auditory stimuli are presented during scanning via a high-fidelity system designed for the MR environment (MR confon GmbH, 39118 Magdeburg, Germany). The headphones contain electrostatic transducers for a broad, flat frequency response and construction-grade Peltor earmuffs for passive damping of gradient noise. By using electrostatic rather than pneumatic transduction, this system produces sound quality comparable to a home stereo, with 88dB signal-to-noise ratio (SNR) and high channel separation. During a functional MRI scanning session, sounds can be presented at detection-threshold levels between "sparse" acquisitions or at conversational levels (approx. 75-80 dB) during continuous scanning. Active Noise Cancellation (ANC) in the headphones will further reduce the gradient noise and create a quieter environment for subjects. ANC is under final pre-release testing at MR-Confon, and the UC Davis IRC will be one of the first centers to use ANC in fMRI research. For communication from the subject, the subject's voice is transmitted to the scan operator via Phone-OR, an MR-compatible, optical microphone mounted on the headphones (Magmedix, Inc., Fitchburg, MA, 01420). This microphone system suppresses gradient noise from the transmitted audio signal, using both simple subtraction and advanced algorithms based on speech-recognition. Combined with the MR confon system, extremely clear bidirectional (subject to/from operator) communication is possible during scanning to provide excellent audio SNR for voice-key applications.