Impaired pitch perception and memory in congenital amusia: the deficit starts in the auditory cortex
Impaired pitch perception and memory in congenital amusia: the deficit starts in the auditory cortex
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DOI：
10.1093/brain/awt082
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发表时间：
2013-05-01
期刊：
影响因子：
14.5
通讯作者：
Tillmann, Barbara
中科院分区：
文献类型：
--
作者：
Albouy, Philippe;Mattout, Jeremie;Tillmann, Barbara
先天性失乐症是一种终生的音乐感知和产生障碍。本研究采用行为测量、脑磁图和基于体素的形态测量法，探讨先天性失乐症患者音高知觉和记忆受损的大脑基础。先天性amusics和匹配的对照组进行两个旋律任务（旋律轮廓任务和一个更容易的换位任务），他们必须指出是否序列的六个音调（成对）是相同的或不同的。行为数据表明，与控制参与者相比，amusics的短期记忆受损的旋律轮廓任务，但不为换位任务。主要的发现是，音高处理和短期记忆缺陷可以追溯到音乐家在编码旋律信息时的早期大脑反应。由旋律的每个音符诱发的N100 m的颞叶和额叶发生器在音乐病患者的大脑中被异常地招募。N100 m的动态因果模型进一步揭示了两个听觉皮层的内在连接性降低，听觉皮层之间的横向连接性增加，以及与对照组相比，amusics的右额颞向后连接性降低。这种额颞叶网络的异常功能也显示在保留间隔和检索旋律信息。特别是，在保留间隔期间，在右额区的诱发伽马振荡减少amusics。使用基于体素的形态测量学，我们证实了形态学异常的大脑中的白色和灰质浓度在右额下回和右上级颞回的音乐失乐症的大脑。功能性和结构性脑差异之间的融合加强了音乐病脑额颞通路异常的假设。我们的数据提供了先天性失乐症患者在音高感知和记忆过程中听觉皮层功能改变的第一个证据。他们进一步支持了这样的假设，即在影响高级功能（这里是音乐能力）的神经发育障碍中，可以在早期大脑反应中观察到大脑处理的异常。
Congenital amusia is a lifelong disorder of music perception and production. The present study investigated the cerebral bases of impaired pitch perception and memory in congenital amusia using behavioural measures, magnetoencephalography and voxel-based morphometry. Congenital amusics and matched control subjects performed two melodic tasks (a melodic contour task and an easier transposition task); they had to indicate whether sequences of six tones (presented in pairs) were the same or different. Behavioural data indicated that in comparison with control participants, amusics' short-term memory was impaired for the melodic contour task, but not for the transposition task. The major finding was that pitch processing and short-term memory deficits can be traced down to amusics' early brain responses during encoding of the melodic information. Temporal and frontal generators of the N100m evoked by each note of the melody were abnormally recruited in the amusic brain. Dynamic causal modelling of the N100m further revealed decreased intrinsic connectivity in both auditory cortices, increased lateral connectivity between auditory cortices as well as a decreased right fronto-temporal backward connectivity in amusics relative to control subjects. Abnormal functioning of this fronto-temporal network was also shown during the retention interval and the retrieval of melodic information. In particular, induced gamma oscillations in right frontal areas were decreased in amusics during the retention interval. Using voxel-based morphometry, we confirmed morphological brain anomalies in terms of white and grey matter concentration in the right inferior frontal gyrus and the right superior temporal gyrus in the amusic brain. The convergence between functional and structural brain differences strengthens the hypothesis of abnormalities in the fronto-temporal pathway of the amusic brain. Our data provide first evidence of altered functioning of the auditory cortices during pitch perception and memory in congenital amusia. They further support the hypothesis that in neurodevelopmental disorders impacting high-level functions (here musical abilities), abnormalities in cerebral processing can be observed in early brain responses.