Centre for Cognitive Neuroscience, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria.
Department of Psychology, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria.
BMC Biol. 2021 Mar 16;19(1):48. doi: 10.1186/s12915-021-00992-8.
A long-standing debate concerns where in the processing hierarchy of the central nervous system (CNS) selective attention takes effect. In the auditory system, cochlear processes can be influenced via direct and mediated (by the inferior colliculus) projections from the auditory cortex to the superior olivary complex (SOC). Studies illustrating attentional modulations of cochlear responses have so far been limited to sound-evoked responses. The aim of the present study is to investigate intermodal (audiovisual) selective attention in humans simultaneously at the cortical and cochlear level during a stimulus-free cue-target interval.
We found that cochlear activity in the silent cue-target intervals was modulated by a theta-rhythmic pattern (~ 6 Hz). While this pattern was present independently of attentional focus, cochlear theta activity was clearly enhanced when attending to the upcoming auditory input. On a cortical level, classical posterior alpha and beta power enhancements were found during auditory selective attention. Interestingly, participants with a stronger release of inhibition in auditory brain regions show a stronger attentional modulation of cochlear theta activity.
These results hint at a putative theta-rhythmic sampling of auditory input at the cochlear level. Furthermore, our results point to an interindividual variable engagement of efferent pathways in an attentional context that are linked to processes within and beyond processes in auditory cortical regions.
关于选择性注意在中枢神经系统（CNS）的处理层次结构中的何处起作用，长期以来一直存在争议。在听觉系统中，耳蜗过程可以通过来自听觉皮层到上橄榄核复合体（SOC）的直接和介导（通过下丘）投射而受到影响。迄今为止，说明耳蜗反应的注意力调节的研究仅限于声音诱发的反应。本研究的目的是在刺激自由的线索-靶间隔期间，同时在皮质和耳蜗水平上研究人类的跨模态（视听）选择性注意。
我们发现，在无声的线索-靶间隔期间，耳蜗活动受到θ节律模式（~6 Hz）的调制。虽然这种模式独立于注意力焦点存在，但当注意即将到来的听觉输入时，耳蜗θ活动明显增强。在皮质水平上，在听觉选择性注意期间发现了经典的后alpha 和 beta 功率增强。有趣的是，在听觉脑区中具有更强抑制释放的参与者显示出对耳蜗θ活动更强的注意力调节。
这些结果暗示了在耳蜗水平上对听觉输入进行可能的θ节律采样。此外，我们的结果表明，在注意力背景下，传出通路的个体间可变性参与与听觉皮质区域内和超越的过程相关联。
