Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre Hvidovre, Denmark ; NeuroImageNord/Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany ; Department of Neurology, Christian-Albrechts-University Kiel, Germany.
NeuroImageNord/Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany ; Department of Psychiatry, Warneford Hospital Oxford, UK.
Front Psychol. 2014 Apr 2;5:274. doi: 10.3389/fpsyg.2014.00274. eCollection 2014.
Functional magnetic resonance imaging (fMRI) studies have provided ample evidence for the involvement of the lateral occipital cortex (LO), fusiform gyrus (FG), and intraparietal sulcus (IPS) in visuo-haptic object integration. Here we applied 30 min of sham (non-effective) or real offline 1 Hz repetitive transcranial magnetic stimulation (rTMS) to perturb neural processing in left LO immediately before subjects performed a visuo-haptic delayed-match-to-sample task during fMRI. In this task, subjects had to match sample (S1) and target (S2) objects presented sequentially within or across vision and/or haptics in both directions (visual-haptic or haptic-visual) and decide whether or not S1 and S2 were the same objects. Real rTMS transiently decreased activity at the site of stimulation and remote regions such as the right LO and bilateral FG during haptic S1 processing. Without affecting behavior, the same stimulation gave rise to relative increases in activation during S2 processing in the right LO, left FG, bilateral IPS, and other regions previously associated with object recognition. Critically, the modality of S2 determined which regions were recruited after rTMS. Relative to sham rTMS, real rTMS induced increased activations during crossmodal congruent matching in the left FG for haptic S2 and the temporal pole for visual S2. In addition, we found stronger activations for incongruent than congruent matching in the right anterior parahippocampus and middle frontal gyrus for crossmodal matching of haptic S2 and in the left FG and bilateral IPS for unimodal matching of visual S2, only after real but not sham rTMS. The results imply that a focal perturbation of the left LO triggers modality-specific interactions between the stimulated left LO and other key regions of object processing possibly to maintain unimpaired object recognition. This suggests that visual and haptic processing engage partially distinct brain networks during visuo-haptic object matching.
功能磁共振成像（fMRI）研究为外侧枕叶（LO）、梭状回（FG）和顶内沟（IPS）在视触觉物体整合中的作用提供了充分的证据。在这里，我们在受试者进行 fMRI 下视触觉延迟匹配样本任务之前，应用 30 分钟的假（非有效）或真实的离线 1Hz 重复经颅磁刺激（rTMS）来干扰左侧 LO 的神经处理。在这个任务中，受试者必须在视触觉或触觉视觉两个方向上匹配顺序呈现的样本（S1）和目标（S2）物体，并决定 S1 和 S2 是否为同一物体。真实 rTMS 在触觉 S1 处理过程中，短暂地降低了刺激部位和远程区域（如右侧 LO 和双侧 FG）的活性。同样的刺激在不影响行为的情况下，在 S2 处理过程中引起了右侧 LO、左侧 FG、双侧 IPS 和其他与物体识别相关的区域的相对激活增加。关键的是，S2 的模态决定了 rTMS 后哪些区域被招募。与假 rTMS 相比，真实 rTMS 在触觉 S2 的左侧 FG 和视觉 S2 的颞极引起了跨模态一致匹配时的相对激活增加。此外，我们发现，对于跨模态触觉 S2 的匹配，在右侧前海马旁回和中额回对于不一致匹配的激活比一致匹配更强，对于单模态视觉 S2 的匹配，在左侧 FG 和双侧 IPS 也是如此，这只发生在真实 rTMS 之后，而不是假 rTMS 之后。结果表明，左侧 LO 的局灶性干扰触发了刺激的左侧 LO 和其他物体处理关键区域之间的模态特异性相互作用，可能是为了保持不受损害的物体识别。这表明在视触觉物体匹配过程中，视觉和触觉处理涉及部分不同的大脑网络。
