Plasticity of the juvenile and adult rodent primary auditory cortex

哺乳动物的大脑在出生后的早期具有高度的可塑性，使发育中的神经系统能够适应出生后经历的特殊环境。初级听觉皮质(A1)负责处理复杂的声音，如通讯信号，幼年动物比成年动物表现出更多的可塑性。然而，即使是成年人的大脑(包括A1)也保持着显著的可塑性潜力，为终身学习提供了神经基础。本申请以大鼠为模型生物，解决了关于发育和成熟A1可塑性的四个基本目标。#1：确定感觉(声音)经验在引导A1突触成熟和稳定方面的确切作用。#2：描述不同听觉感知技能的后天发展(例如，对响度、音调或节奏模式的辨别)以及早期声音经验对这一发展轨迹的影响。#3：评估成人A1区听觉学习的突触机制。#4：确定大脑产生的雌激素(由A1神经元合成和释放)在A1可塑性和听觉学习中的作用。这些目标是通过在发育过程中对声环境的精确操纵、允许动物学习区分各种声音的行为技术以及评估A1神经元表达的可塑性水平的电生理学和药理学技术来实现的。这一研究计划为高素质人才创造了丰富的培训机会，使研究生和本科生能够掌握尖端的科学和专业技能，从而为他们在学术或工业/技术环境中的高级职业生涯做好准备。总体而言，这里概述的研究将极大地促进我们对成年动物听觉感知技能和听觉学习发展的理解，包括调节这些现象的大脑机制。鉴于听觉信号在动物(包括人类)交流中的重要性，这项工作还可以为许多哺乳动物物种复杂的交流能力中介的感觉和大脑系统的进化和发展提供见解。

Mammalian brains are highly plastic during early postnatal life, allowing the developing nervous system to adapt to the particular environment experienced after birth. The primary auditory cortex (A1), responsible for processing complex sounds such as communication signals, exhibits substantially more plasticity in juvenile animals than in adults. However, even adult brains (including A1) retain a significant plasticity potential, providing the neural basis for life-long learning. The present application addresses four fundamental objectives regarding plasticity of the developing and mature A1, using rats as a model organism. #1: Determine the precise role of sensory (sound) experience in guiding the maturation and stabilization of A1 synapses. #2: Characterize the postnatal development of different auditory perceptual skills (e.g., discrimination of loudness, pitch, or rhythmic patterns) and the influence of early sound experience on this developmental trajectory. #3: Assess synaptic mechanisms of auditory learning in the adult A1. #4: Determine the role of brain-generated estrogen (synthesized and released by A1 neurons) in A1 plasticity and auditory learning. These objectives are met by precise manipulations of the acoustic environment during development, behavioral techniques allowing animals to learn to distinguish various sounds, as well as electrophysiological and pharmacological techniques to assess levels of plasticity expressed by A1 neurons. This research program creates rich training opportunities for highly qualified personnel, allowing graduate and undergraduate students to acquire mastery of sophisticated scientific and professional skills, thus preparing them for advanced careers in academic or industrial/technological settings. Overall, the research outlined here will significantly advance our understanding of the development of auditory perceptual skills and auditory learning in adult animals, including brain mechanisms mediating these phenomena. Given the importance of auditory signals in animal (including humans) communication, this work can also provide insights into the evolution and development of sensory and brain systems mediating the sophisticated communicative abilities of many mammalian species.