Contribution of local- and circuit-based mechanisms to adaptive coding in the auditory midbrain

基于局部和电路的机制对听觉中脑自适应编码的贡献

• 批准号: BB/H00369X/1
• 负责人: David McAlpine
• 金额: $ 50.27万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FH00369X%2F1
• 关键词: Contribution; local; circuit; based; mechanisms

The ability to code accurately the prevailing sensory information is critical to an animal's survival, and brain mechanisms have evolved that enable this information to be extracted from the environment in an optimal manner. As part of this ability, many sensory neurons appear able to adjust their neural tuning in 'real-time' to take account of the unfolding sensory environment. This so-called 'adaptive coding' often results in improved accuracy with which the ambient sensory environment is coded. How this is achieved in the brain remains to be determined, both in terms of cellular mechanisms and in terms of brain circuits that contribute to adaptive coding in any one brain centre. Our experiments will investigate three specific aspects of adaptive coding. First, they will determine mechanisms within neurons themselves that contribute to adaptive coding for the unfolding sound intensities present in a sound. Second, they will assess the contribution of cortical feedback on adaptive coding in lower brain centres. Although sensory information is thought to 'flow' from the peripheral hearing sensors in the ears towards higher brain centres such as the cortex, a substantial number of cortical feedback circuits are also known to exist. The function of these feddback circuits remains unclear, but preliminary evidence from my laboratory suggests that one role is to modify adaptive coding in the auditory midbrain, increasing the time taken by neurons to optimise their sensitivity to sound intensity when the prevailing sound enviroment suddenly changes. Finally, experiments will also examine how specific adaptive coding is for the stimulus feature currently being heard, assessing whether or not adapting a neuron's response to one stimulus parameter (e.g. sound intensity) also means that the responses are adapted to sound-source location, for example.

准确编码主要感官信息的能力对动物的生存至关重要，大脑机制已经进化，使这些信息能够以最佳方式从环境中提取。作为这种能力的一部分，许多感觉神经元似乎能够“实时”调整它们的神经调谐，以考虑正在展开的感觉环境。这种所谓的“自适应编码”通常导致周围感觉环境被编码的精度提高。这在大脑中是如何实现的还有待确定，无论是在细胞机制方面，还是在任何一个大脑中心有助于适应性编码的大脑回路方面。我们的实验将研究自适应编码的三个具体方面。首先，他们将确定神经元自身的机制，这些机制有助于对声音中存在的展开声音强度进行自适应编码。第二，他们将评估皮层反馈对低脑中心适应性编码的贡献。虽然感觉信息被认为是从耳朵中的外围听觉传感器“流动”到更高的大脑中心，如皮层，但也存在大量的皮层反馈回路。这些反馈回路的功能尚不清楚，但我实验室的初步证据表明，其中一个作用是修改听觉中脑的自适应编码，当主要的声音环境突然改变时，增加神经元优化其对声音强度敏感性的时间。最后，实验还将检查自适应编码对于当前听到的刺激特征的具体程度，评估神经元对一个刺激参数（例如声音强度）的反应是否也意味着反应适应于声源位置，例如。