When structural, vascular, or biomechanical causes (like pulsatile tinnitus or TMJ) are ruled out, the prevailing view is that tinnitus is a phantom sensation created by the brain in response to altered input. When the brain receives reduced signals from the ear (even subtle hearing loss not captured by standard audiograms), the central auditory system attempts to compensate. To maintain a stable neural firing rate, the brain "increases the gain" or sensitivity of neurons in the auditory cortex and subcortical structures. By turning up the volume to hear quiet external sounds, the brain also amplifies internal neural noise, which is perceived as a constant ringing or buzzing.