Department of General Psychology, University of Padova, Padova, Italy.
Neuropsychologia. 2011 Aug;49(10):2929-34. doi: 10.1016/j.neuropsychologia.2011.06.020. Epub 2011 Jun 24.
Adaptation to directional motion has been shown to bias the perceived direction of a subsequently presented stationary or flickering test stimulus toward the opposite direction with respect to that of adaptation. This phenomenon, called motion aftereffect, is usually generated with adaptation periods of tens of seconds or minutes and has been shown to depend upon the functional integrity of visual area V5/MT. Rapid forms of MAE, arising and decaying within half a second (rMAE), can also be generated with sub-second adaptation durations. In order to investigate the neural substrate underlying the rMAE, repetitive transcranial magnetic stimulation (rTMS) has been used just after the adaptation stimulus over areas V1/V2, V5/MT, or over the vertex. Results showed that, besides some reduction in strength of the rMAE when rTMS was delivered over V5/MT, it was maximally disrupted when stimulation was delivered over early visual areas V1/V2. This is the first study where a causal role of early visual cortices in MAE is demonstrated. Moreover, this finding supports the existence of multiple loci along the visual stream in which gain control takes place and generates the MAE as a byproduct. The specific locus is likely to depend on the specific stimulus used.
适应方向运动已被证明会使随后呈现的静止或闪烁测试刺激的感知方向偏向适应方向的相反方向。这种现象称为运动后效，通常在数十秒或数分钟的适应期内产生，并且已经表明它依赖于视觉区域 V5/MT 的功能完整性。快速形式的 MAE（rMAE）也可以在亚秒级的适应持续时间内产生，其在半秒内出现和消失。为了研究 rMAE 的神经基础，在适应刺激之后，使用重复经颅磁刺激（rTMS）在 V1/V2、V5/MT 或头顶上方的区域进行刺激。结果表明，除了在 V5/MT 上方施加 rTMS 时 rMAE 的强度降低外，当刺激施加在早期视觉区域 V1/V2 上方时，rMAE 最大程度地受到干扰。这是第一项证明早期视觉皮层在 MAE 中具有因果作用的研究。此外，这一发现支持了在视觉流中存在多个位置，增益控制发生在这些位置，并产生 MAE 作为副产品。特定位置可能取决于所使用的特定刺激。
