( C) Neurometric functions from one multiunit recorded during task performance improved across days. Data from this animal are presented in C– G. ( B) Psychometric functions from one animal improved across days. ( A) Wireless recordings were made from ACx of animals as they performed an AM detection task. Cortical and behavioral improvements are similar in magnitude and time course. S1 C) without increasing false alarm rates ( P = 0.63 SI Appendix, Fig. S1 B) by reducing hit rates ( P < 0.0001 SI Appendix, Fig.
At this concentration, muscimol significantly impaired AM detection ( P = 0.0006 SI Appendix, Fig. To determine whether this auditory percept required ACx activity, we infused a high dose of muscimol (1 mg/mL 1 μL per hemisphere total dose of 2 μg) bilaterally in four animals ( SI Appendix, Fig. All animals learned this procedure quickly, reaching our performance criterion ( d′ > 1.5) within four training sessions (2.1 ± 0.18 sessions, n = 16 animals across all experiments see SI Appendix, Materials and Methods). Animals were trained to drink from a water spout while in the presence of the “safe” stimulus (unmodulated noise), and to withdraw from the spout when the sound changed to the “warn” stimulus (0 dB relative to 100% depth, 5-Hz AM noise), to avoid an aversive shock. 1 A), a perceptual skill that displays significant improvement in humans ( 35). We trained Mongolian gerbils on an amplitude modulation (AM) detection task ( Fig. Collectively, our findings suggest that training facilitates perceptual learning by strengthening both bottom-up sensory encoding and top-down modulation of auditory cortex. Targeted reduction of auditory cortical activity during training diminished perceptual learning while leaving psychometric performance largely unaffected. In contrast, during nontask listening sessions, cortical improvements were weak and uncorrelated with perceptual performance. During task performance, cortical improvements were large and predicted behavioral outcomes. Surprisingly, the degree of neural improvement was behaviorally gated.
Training led to improvements in cortical and behavioral sensitivity that were closely matched in terms of magnitude and time course. To address these issues, we recorded the activity of auditory cortical neurons as gerbils trained on a sound detection task. Furthermore, the temporal relationship between neural and behavioral plasticity remains uncertain.
Although several brain regions and neural mechanisms have been proposed to support perceptual learning, formal tests of causality are lacking. Practice sharpens our perceptual judgments, a process known as perceptual learning.