Cortical evoked response to gaps in noise: Within-channel and across-channel conditions
Cortical evoked response to gaps in noise: Within-channel and across-channel conditions
复制标题
DOI：
10.1097/aud.0b013e3181576cba
复制
发表时间：
2007-12-01
期刊：
影响因子：
3.7
通讯作者：
Pitt, Gabriel J.
中科院分区：
文献类型：
--
作者：
Lister, Jennifer J.;Maxfield, Nathan D.;Pitt, Gabriel J.
目的：本研究的目的是描述一组听力正常的年轻人使用相同的刺激条件下，在心理物理学研究的间隙检测的皮层诱发反应无声的差距。具体来说，我们试图检查P1-N1-P2听觉诱发反应的起始刺激（标记）定义一个沉默的差距通道内（光谱相同的标记）和跨通道（光谱不同的标记）的条件，使用四个感知等同的间隙持续时间。假设（1）P1、N1和P2将存在并且与第一标记一致（在差距之前）开始;（2）对于通道内标记，第2个标记将存在P1、N1和P2（在差距之后）仅当差距的持续时间等于或大于行为测量的间隙检测阈值时才开始;以及（3）对于跨信道条件，P1、N1和P2对于第二标记起始将存在，而不管间隙持续时间。这是预期的，由于额外的提示频率变化以下的差距。设计：12个年轻的成年人（平均年龄26岁）与正常的听力参加。通道内和跨通道间隙检测阈值确定使用自适应心理物理过程。接下来是皮层听觉诱发电位（P1-N1-P2）用32通道Neuroscan（TM）脑电图系统记录，使用与心理物理任务相同的通道内和跨通道标记，以及四个感知加权间隙持续时间：（1）个体听者的间隙检测阈值;（2）高于间隙检测阈值;（3）低于间隙检测阈值;以及（4）与心理物理任务的标准间隔中的间隙相同的差距。P1-N1-P2峰潜伏期和振幅采用重复测量方差分析。结果：P2潜伏期和P1、N1、P2波幅受第二标记的声学特征和差距的持续时间的影响。通常在声学线索最显著的条件下发现较大的振幅和较短的潜伏期（例如，跨通道标记、第一标记、大间隙持续时间）。有趣的是，时间-空间的主成分分析显示，活动引起的间隙持续时间等于间隙检测阈值在潜伏期区域的167和183 ins的颞顶叶和右额叶spatial locations.Conclusions：皮层响应一个沉默的间隙是独特的特定标记特征和间隙持续时间之间的年轻人听力正常。具体而言，当第二标记的发作是感知显着的，P1-N1-P2响应的幅度相对较大，P2潜伏期相对较短，比非显着的第二标记发作，提供非侵入性的，非行为指标的神经编码的中枢听觉系统的丘脑-皮层区域中的这个重要的时间线索。间隙持续时间似乎是最清楚地表明P1和T复合波振幅。
Objectives: The objective of this study was to describe the cortical evoked response to silent gaps in a group of young adults with normal hearing using stimulus conditions identical to those used in psychophysical studies of gap detection. Specifically, we sought to examine the P1-N1-P2 auditory evoked response to the onsets of stimuli (markers) defining a silent gap for within-channel (spectrally identical markers) and across-channel (spectrally different markers) conditions using four perceptually-equated gap durations. It was hypothesized that (1) P1, N1, and P2 would be present and consistent for 1st marker (before the gap) onsets; (2) for within-channel markers, P1, N1, and P2 would be present for 2nd marker (after the gap) onsets only when the gap was of a duration equal to or larger than the behaviorally measured gap detection threshold; and (3) for the across-channel conditions, P1, N1, and P2 would be present for 2nd marker onsets regardless of gap duration. This is expected due to the additional cue of frequency change following the gap.Design: Twelve young adults (mean age 26 years) with normal hearing participated. Within-channel and across-channel gap detection thresholds were determined using an adaptive psychophysical procedure. Next, cortical auditory evoked potentials (P1-N1-P2) were recorded with a 32-channel Neuroscan (TM) electroencephalogram system using within-channel and across-channel markers identical to those used for the psychophysical task and four perceptually weighted gap durations: (1) individual listener's gap detection threshold; (2) above gap detection threshold; (3) below gap detection threshold; and (4) a 1-ms gap identical to the gap in the standard interval of the psychophysical task. P1-N1-P2 peak latencies and amplitudes were analyzed using repeated-measures analyses of variance. A temporal-spatial principal component analysis was also conducted.Results: The latency of P2 and the amplitude of P1, N1, and P2 were significantly affected by the acoustic characteristics of the 2nd marker as well as the duration of the gap. Larger amplitudes and shorter latencies were generally found for the conditions in which the acoustic cues were most salient (e.g., across-channel markers, 1st markers, large gap durations). Interestingly, the temporal-spatial principal component analysis revealed activity elicited by gap durations equal to gap detection threshold in the latency regions of 167 and 183 ins for temporal-parietal and right-frontal spatial locations.Conclusions: The cortical response to a silent gap is unique to specific marker characteristics and gap durations among young adults with normal hearing. Specifically, when the onset of the 2nd marker is perceptually salient, the amplitude of the P1-N1-P2 response is relatively larger and the P2 latency is relatively shorter than for nonsalient 2nd marker onsets, providing noninvasive, nonbehavioral indicators of the neural coding of this important temporal cue in the thalamic-cortical region of the central auditory system. Gap duration appears to be most clearly indicated by P1 and T-complex amplitude.