Steinmann Saskia, Leicht Gregor, Ertl Matthias, Andreou Christina, Polomac Nenad, Westerhausen René, Friederici Angela D, Mulert Christoph
Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg - Eppendorf, Hamburg, Germany.
Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway; Division of Psychiatry, Haukeland Hospital, Bergen, Norway.
Neuroimage. 2014 Oct 15;100:435-43. doi: 10.1016/j.neuroimage.2014.06.012. Epub 2014 Jun 17.
While the role of synchronized oscillatory activity in the gamma-band frequency range for conscious perception is well established in the visual domain, there is limited evidence concerning neurophysiological mechanisms in conscious auditory perception. In the current study, we addressed this issue with 64-channel EEG and a dichotic listening (DL) task in twenty-five healthy participants. The typical finding of DL is a more frequent conscious perception of the speech syllable presented to the right ear (RE), which is attributed to the supremacy of the contralateral pathways running from the RE to the speech-dominant left hemisphere. In contrast, the left ear (LE) input initially accesses the right hemisphere and needs additional transfer via interhemispheric pathways before it is processed in the left hemisphere. Using lagged phase synchronization (LPS) analysis and eLORETA source estimation we examined the functional connectivity between right and left primary and secondary auditory cortices in the main frequency bands (delta, theta, alpha, beta, gamma) during RE/LE-reports. Interhemispheric LPS between right and left primary and secondary auditory cortices was specifically increased in the gamma-band range, when participants consciously perceived the syllable presented to the LE. Our results suggest that synchronous gamma oscillations are involved in interhemispheric transfer of auditory information.
虽然在视觉领域，γ波段频率范围内的同步振荡活动在意识感知中的作用已得到充分证实，但关于意识听觉感知的神经生理机制的证据却很有限。在本研究中，我们通过64通道脑电图和双耳分听（DL）任务，对25名健康参与者进行了研究，以解决这一问题。DL的典型发现是，人们对呈现给右耳（RE）的语音音节的意识感知更为频繁，这归因于从RE到语言优势半球——左半球的对侧通路的优势。相比之下，左耳（LE）的输入最初进入右半球，在左半球进行处理之前，需要通过半球间通路进行额外传输。我们使用滞后相位同步（LPS）分析和eLORETA源估计，在RE/LE报告期间，检查了左右初级和次级听觉皮层在主要频段（δ、θ、α、β、γ）之间的功能连接。当参与者有意识地感知呈现给LE的音节时，左右初级和次级听觉皮层之间的半球间LPS在γ波段范围内显著增加。我们的结果表明，同步γ振荡参与了听觉信息的半球间传递。
