A cortico-collicular network for hearing and noise avoidance responses in bats

对于利用声音进行导航（回声定位）和社会交流的动物来说，声学噪声是干扰的主要来源。噪音可以掩盖对相关刺激的感官反应，从而影响与环境的协调能力。为了避免噪音，动物们依靠各种各样的行为，比如提高叫声的水平，改变叫声的音调和时间。避声是主动感知的一个典型例子，在这种情况下，动物依靠噪音的感官表征来调整它们叫声的物理属性。本研究旨在探讨蝙蝠额叶皮层、听觉皮层和下丘组成的皮质-皮质下网络在躲避噪声中的作用。蝙蝠是研究听觉和发声行为的一种成熟的动物模型，因此它们为研究噪声避免电路提供了强有力的理论框架。我们的指导假设是，噪声避免涉及到上升和下降神经通路之间的相互作用，这些神经通路连接皮层和皮层下结构，形成直接和间接的感知回路。我们提出了一个串联项目，其中一个实验家（Hechavarria, GU Frankfurt am Main）和一个计算小组（Triesch， FIAS, Frankfurt am Main）将合作记录，建模和干扰额叶皮层-听觉皮层-下丘网络。在我们的实验中，当蝙蝠在钟摆上摆动时，它们会在嘈杂和安静的环境中进行回声定位。我们将：i)同时记录行为蝙蝠的皮层和皮层下区域，ii)通过使专注于额叶皮层的大脑区域失活来干扰神经活动，以及iii)开发具有前馈和反馈连接的模型，以了解皮质-中脑回路如何参与嘈杂环境中有效的信息编码。

Acoustic noise is a main source of disturbance for animals that use sounds for navigation (echolocation) and social communication. Noise can mask sensory responses to relevant stimuli and thus affect the ability to negotiate the environment. To avoid noise, animals rely on a variety of behaviors such as increasing call level and modifying the pitch and timing of vocalizations. Noise avoidance is a typical example of active sensing in which animals rely on sensory representations of the noise to adjust the physical attributes of their calls. The aim of this project is to investigate the role of the cortico-subcortical network composed of frontal cortex, auditory cortex and inferior colliculus in noise avoidance in bats. Bats are a well-established animal model for research in hearing and vocal behavior, and they thus provide a strong theoretical framework for studying noise avoidance circuits. Our guiding hypothesis is that noise avoidance involves an interplay between ascending and descending neural pathways that connect cortical and subcortical structures forming direct and indirect sensing loops. We propose a tandem project in which an experimentalist (Hechavarria, GU Frankfurt am Main) and a computational group (Triesch, FIAS, Frankfurt am Main) will team-up to record, model, and perturb the frontal cortex-auditory cortex-inferior colliculus network. In our experiments, bats will echolocate in noisy and quiet environments while they are swung in a pendulum. We will: i) record from cortical and subcortical areas simultaneously in behaving bats, ii) perturb neural activity by deactivating brain areas with focus on the frontal cortex, and iii) develop models with feedforward and feedback connectivity to understand how cortico-midbrain loops participate in the active efficient coding of information in noisy environments.