Fig. 5.

Top-down modulation of auditory cortex during perceptual learning. A Mongolian gerbils were trained to drink from a spout while in the presence of continuous, unmodulated broadband noise and to cease drinking when the noise smoothly transitioned to an amplitude modulated (AM) noise. Single- and multi-unit recordings were obtained wirelessly from the auditory cortex of these animals as they trained with a range of AM depths. Over the course of several days of training, animals improve their ability to detect more subtle modulations, such that their psychometric thresholds gradually improve. B Amplitude modulation detection thresholds of auditory cortical neurons were lower (better) when animals engaged in the AM detection task (blue) compared to when they were passively exposed to sounds (green). This task-related enhancement of auditory cortical sensitivity (orange arrows) increased over the course of perceptual learning. C These data are consistent with the idea that behavioral performance engages higher order, top-down brain networks that enhance auditory cortical responses and suggests that this putative top-down enhancement grows larger over the course of perceptual learning. Adapted from Caras and Sanes (2017).