Frontiers in Aging Neuroscience Aging Neuroscience

Abstract

In the auditory pathway, neurons in the auditory brainstem and midbrain nuclei respond to temporal stimuli in a stimulus synchronized manner (Frisina et al., 1990a,b). These phase locked responses in the brainstem and the midbrain recorded as auditory evoked potentials have developed into indispensable diagnostic tools for assessing hearing loss and auditory neural Auditory brainstem responses (ABRs) are the predominant physiologic measure of hearing sensitivity and are typically evoked by brief click or tone stimuli (Hall, 2006). However, many speech sounds and other behaviorally relevant sounds last for tens to hundreds of milliseconds and contain periodic components (Rosen, 1992). Such stimuli can be tracked using either the frequency following response (FFR) to track low carrier frequencies or the amplitude modulation following response (AMFR) to track changes in the modulation envelope (Picton et al., 2003). The FFR and the AMFR are the summed synchronized population responses of spiking activity and synaptic potentials of neurons in the auditory brainstem and midbrain (Herdman et al., 2002).