School of Psychology, South China Normal University, Guangzhou, China; Donders Institute for Brain, Cognition and Behaviour, Radboud University, Kapittelweg 29, 6525 EN, Nijmegen, the Netherlands.
Donders Institute for Brain, Cognition and Behaviour, Radboud University, Kapittelweg 29, 6525 EN, Nijmegen, the Netherlands.
Neuroimage. 2019 Oct 15;200:242-249. doi: 10.1016/j.neuroimage.2019.06.033. Epub 2019 Jun 20.
The auditory cortex is sensitive to many forms of acoustic regularity, resulting in suppressed neural activity for expected auditory events. It is unclear whether this activity reduction for expected events is the result of suppression of neurons that are tuned to the expected stimulus (i.e., dampening), or alternatively suppression of neurons that are tuned away from the expected stimulus (i.e., sharpening). In the present study, we adjudicated between these models by characterizing the effect of expectation on the ability to classify the identity of auditory stimuli from auditory neural activity patterns, using magnetoencephalography (MEG) in healthy human observers. Participants listened to pure tone pairs, in which the identity of the second tone was either expected or unexpected. The task of the participants was to detect a target tone, which deviated strongly from both the expected and unexpected tones. We found a strong suppression of the overall neural response in the expected condition compared to the unexpected condition. Linear classifiers showed a reduced ability to decode stimulus identity from event-related auditory fields in the expected condition compared to the unexpected condition. This suggests that stimulus-specific event-related activity is dampened for expected tones in auditory cortex.
听觉皮层对多种形式的声学规则敏感，导致对预期听觉事件的神经活动受到抑制。目前尚不清楚这种对预期事件的活动减少是由于对预期刺激调谐的神经元的抑制（即减敏），还是由于对远离预期刺激调谐的神经元的抑制（即锐化）所致。在本研究中，我们通过使用健康人类观察者的脑磁图（MEG）来从听觉神经活动模式中对听觉刺激的身份进行分类，来对这些模型进行裁决。参与者听纯音对，其中第二音的身份是预期的还是意外的。参与者的任务是检测偏离预期和意外音调都很强的目标音调。与意外条件相比，在预期条件下，整体神经反应受到强烈抑制。线性分类器显示，与意外条件相比，在预期条件下，从与事件相关的听觉场解码刺激身份的能力降低。这表明，在听觉皮层中，预期音调的刺激特异性与事件相关的活动被减弱。
