Paraouty, N. | bioRxiv Science

bioRxiv2023

Predictable sequential structure enhances auditory sensitivity in clinical audiograms

Human hearing is highly sensitive and allows us to detect acoustic events at low levels. However, sensitivity is not only a function of the integrity of cochlear transduction mechanisms, but also constrained by central processes such as attention and expectation. While the effects of distraction and attentional orienting are generally acknowledged, the extent to which probabilistic expectations influence sensitivity at threshold is not clear. Classical audiometric tests, commonly used to assess hearing thresholds, do not distinguish between bottom-up sensitivity and top-down processes. In this study, we aim to decipher the influence of various types of expectations on hearing thresholds and how this information can be used to improve the assessment of hearing sensitivity. Our results raise important questions regarding the conventional assessment of hearing thresholds, both in fundamental research and in audiological clinical assessment.

animal behavior and cognition↗

bioRxiv2021

Dopaminergic signaling supports auditory social learning

Explicit rewards are commonly used to reinforce a behavior, a form of learning that engages the dopaminergic neuromodulatory system. In contrast, skill acquisition can display dramatic improvements from a social learning experience, even though the observer receives no explicit reward. Here, we test whether a dopaminergic signal contributes to social learning in naive gerbils that are exposed to, and learn from, a skilled demonstrator performing an auditory discrimination task. Following five exposure sessions, naive observer gerbils were allowed to practice the auditory task, and their performance was assessed across days. We first tested the effect of an explicit food reward in the observers compartment that was yoked to the demonstrators performance during exposure sessions. Naive observer gerbils with the yoked reward learned the discrimination task significantly faster, as compared to unrewarded observers. The effect of this explicit reward was abolished by administration of a D1/D5 dopamine receptor antagonist during the exposure sessions. Similarly, the D1/D5 antagonist reduced the rate of learning in unrewarded observers. To test whether a dopaminergic signal was sufficient to enhance social learning, we administered a D1/D5 receptor agonist during the exposure sessions in which no reward was present, and found that the rate of learning occurred significantly faster. Finally, a quantitative analysis of observer vocalizations and movements during the exposure sessions suggest behavioral strategies that contribute to social learning. Together, these results are consistent with a dopamine-dependent reward signal during social learning.

neuroscience↗