Department of Psychiatry, University of Colorado Denver Anschutz Medical Campus, 13001 E, 17th Place, Aurora, CO 80045, USA.
BMC Psychiatry. 2012 Nov 29;12:213. doi: 10.1186/1471-244X-12-213.
Synchronous neural oscillatory activity in the gamma range (30-80 Hz) has been shown to be abnormal in individuals with autism spectrum disorders (ASD) and their first-degree relatives in response to simple auditory stimuli. Gamma-band abnormalities in ASD probands have been seen in response to language stimuli, but this has not been investigated in first-degree relatives. This is of particular interest given that language impairments are a core symptom of ASD and may be part of the broad autism phenotype (BAP) seen in relatives.
Magnetoencephalography recordings during a continuous word recognition task were obtained for 23 parents of a child with ASD (pASD) and 28 adult control participants. Total and evoked gamma-band activity, as well as inter-trial phase-locking factor (PLF), were measured in response to the task. Beta-band activity was also measured, due to its suggested role in language processing. Participants completed a series of language measures to assess the relationship between brain activity and language function, and lateralization of task-related activity was assessed.
The pASD group showed increased evoked gamma and beta activity, while controls had decreased evoked activity. Additionally, while both groups showed a reduction in total gamma power (commonly seen in language tasks), this reduction was more prominent in the control group. The pASD group demonstrated significantly worse performance on a measure of phonology compared to controls. Significant but distinct relationships were found between gamma/beta activity and language measures within the two groups. In addition, while the overall task generally elicited left lateralized responses, pASD showed greater left lateralization than controls in some regions of interest.
Abnormalities in oscillatory responses to language were seen in pASD that are consistent with previous findings in ASD probands. Gamma-band responses to language stimuli have not previously been assessed in first-degree relatives of ASD probands and these findings are supportive of gamma-band activity as a heritable, neurophysiological biomarker of ASD. The possible relationship seen between language function and neural activity in the current study should be investigated further to assess if oscillatory response abnormalities may contribute to behavioural manifestations of the BAP.
在对简单听觉刺激的反应中，已显示患有自闭症谱系障碍（ASD）及其一级亲属的个体的γ频带（30-80 Hz）同步神经振荡活动异常。在 ASD 先证者对语言刺激的反应中也观察到了γ频带异常，但尚未在一级亲属中进行研究。这一点特别有趣，因为语言障碍是 ASD 的核心症状，并且可能是在亲属中看到的广泛自闭症表型（BAP）的一部分。
对 23 名 ASD 儿童的父母（pASD）和 28 名成年对照组参与者在进行连续单词识别任务期间进行了脑磁图记录。针对该任务，测量了总γ带和诱发γ带活动以及试验间相位锁定因子（PLF）。由于其在语言处理中的作用，还测量了β带活动。参与者完成了一系列语言测试，以评估大脑活动与语言功能之间的关系，并评估与任务相关的活动的偏侧化。
pASD 组表现出诱发γ带和β带活动增加，而对照组表现出诱发活动减少。此外，尽管两组的总γ带功率都降低（在语言任务中通常会看到），但对照组的降低更为明显。与对照组相比，pASD 组在语音测试中表现出明显更差的成绩。在两组中，均发现γ/β活动与语言测量之间存在显著但不同的关系。此外，尽管整个任务通常会引起左侧反应，但 pASD 显示出比对照组更大的左侧化，在一些感兴趣的区域。
在 pASD 中观察到对语言的振荡反应异常，与 ASD 先证者的先前发现一致。先前尚未在 ASD 先证者的一级亲属中评估过语言刺激的γ带反应，这些发现支持γ带活动作为 ASD 的可遗传神经生理生物标志物。目前研究中观察到的语言功能与神经活动之间的可能关系应进一步研究，以评估振荡反应异常是否可能导致 BAP 的行为表现。
