TY - JOUR T1 - Tracking Down Nonresponsive Cortical Neurons in Cochlear Implant Stimulation JF - eneuro JO - eNeuro DO - 10.1523/ENEURO.0095-17.2017 VL - 4 IS - 3 SP - ENEURO.0095-17.2017 AU - Charlotte Amalie Navntoft Y1 - 2017/05/01 UR - http://www.eneuro.org/content/4/3/ENEURO.0095-17.2017.abstract N2 - The cochlear implant (CI) can restore a sense of hearing to deaf people. Although it works well in quiet situations, most CI users still struggle to follow conversations in noisy environments and perceive music. One challenge in CI stimulation is that the brain must resolve and interpret the signal to generate meaningful and goal-oriented hearing. How efficient this process is and how the underlying neuronal circuits respond, or fail to respond, to such input compared with normally transmitted sound is essentially unknown. Understanding these central auditory mechanisms is crucial for the further development of CIs. In a recent study published in The Journal of Neuroscience, Johnson et al. (2016) investigated how CI stimulation engages the auditory cortex in awake marmosets. There were two main findings: first, CIs are surprisingly inefficient in activating cortical neurons that normally respond to sound; second, CI-responsive neurons are functionally different from non–CI-responsive neurons. Here, we discuss the results and hypothesize how inhibition could be involved the brain’s response to CIs. Sound travels from its source to the ear, and further on eventually to the brain, through a chain of biological mechanisms that convert vibrations in the air into nerve impulses. In deaf people, the link between sensory hair cells and the auditory nerve in the cochlear is often broken (or the terminals of the auditory nerve are simply gone), and the auditory input therefore never reaches the brain. Cochlear implants (CIs) bypass this missing link by directly stimulating the auditory nerve. To date, this approach has restored hearing sensation to >300,000 severely and profoundly deaf people.Present-day design of CIs is based on a bottom-up approach in which the goal is to reproduce normal patterns of neural activity at the auditory periphery. In a recent study published in The Journal of Neuroscience, Johnson … ER -