TEMPORAL DYNAMICS OF CENTRAL AUDITORY PROCESSING

中枢听觉处理的时间动态

• 批准号: 6698079
• 负责人: Alexander Galazyuk
• 金额: $ 19万
• 依托单位: NORTHEAST OHIO MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-16 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6698079
• 关键词: Chiroptera; auditory discrimination; auditory pathways; auditory stimulus; auditory threshold; electrodes; electrophysiology; inferior colliculus; microinjections; neural information processing; neurons; sound frequency; sound perception

DESCRIPTION (provided by applicant): The overall aim of this research program is to investigate how the time interval between temporally discrete sounds in a sequence influences the fundamental response properties of central auditory neurons. Sounds produced in sequences are common to most bioacoustics signals such as the biosonar sounds used by bats and communication sounds including speech. Recent studies in the inferior colliculus (IC) of bats show a progressive increase in amplitude selectivity of neurons to sounds in a sequence when the rate of acoustic stimulation is increased. Pilot studies have revealed that the rate of stimulation has a more global impact on an IC unit's responses across several dimensions, including the unit's frequency selectivity. In addition, the ability of human listeners to discriminate small differences in sound level improves with increased rate of acoustic stimulation during psychophysical experiments. Therefore, understanding the mechanisms that underlie rate-dependent changes in amplitude and frequency selectivity could not only explain behavioral performance of echo locating bats, but it could also advance our understanding of speech processing in humans. Three specific aims will be addressed. Aim #1 is to characterize quantitatively the response selectivity's of single neurons in the IC to sound frequency when the stimuli are presented at different pulse repetition rates to test the hypothesis that frequency selectivity is dependent upon the rate of stimulation, i.e., the selectivity is greater when the tone pulses are presented at higher repetition rates. Aim #2 is to determine the minimum number of tone pulses in a train required for a change in amplitude selectivity to test the hypothesis that the amplitude and frequency selectivity's of IC neurons to a sound pulse can be enhanced in the presence of as few as one preceding sound pulse. Aim #3 is to study the postsynaptic events that underlie the rate-dependence in amplitude and frequency selectivity's in single IC neurons, using extracellular microiontophoretic injection techniques and intracellular recording to test the hypothesis that inhibition is more robust when sound pulses are presented at high than low repetition rates.

描述（由申请人提供）：该研究计划的总体目的是研究序列中时间离散声音之间的时间间隔如何影响中央听觉神经元的基本响应属性。序列产生的声音对于大多数生物源信号来说都是常见的，例如蝙蝠使用的生物声音和包括语音在内的通讯声音。蝙蝠下丘（IC）的最新研究表明，当声学刺激的速率增加时，神经元对声音的振幅选择性逐渐增加。试点研究表明，刺激速率对IC单元在几个维度的响应（包括单元的频率选择性）上的响应具有更大的全球影响。另外，在心理物理实验期间，听众歧视声音水平的微小差异的能力会提高声音水平的差异。因此，了解基于速率依赖性幅度和频率选择性变化的机制不仅可以解释回声定位蝙蝠的行为性能，而且还可以提高我们对人类中语音处理的理解。将解决三个具体目标。目的＃1是在以不同的脉冲重复率以不同的脉冲重复速率显示刺激时进行定量表征IC中单个神经元对声频的响应选择性，以检验以下假说：频率选择性取决于刺激速率，即，当音调脉冲以较高的重复速率显示时，选择性更大。 AIM＃2是确定更改幅度选择性所需的最小音调脉冲数量，以测试以下假设，即IC神经元的振幅和频率选择性对声音脉冲的振幅和频率选择性可以在与先前的声音脉冲的情况下更少。目的＃3是研究单个IC神经元中振幅和频率选择性依赖性的突触后事件，使用细胞外微噬菌体注入技术和细胞内记录，以测试当声音脉冲以高于低重率的速率以高率显示出声音时，抑制作用更强。