The role of human extra-striate visual areas V5/MT and V2/V3 in the perception of the direction of global motion: a transcranial magnetic stimulation study
The role of human extra-striate visual areas V5/MT and V2/V3 in the perception of the direction of global motion: a transcranial magnetic stimulation study
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DOI：
10.1007/s00221-006-0479-6
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发表时间：
2006-06-01
影响因子：
2
通讯作者：
Vaina, Lucia M.
中科院分区：
文献类型：
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作者：
Cowey, Alan;Campana, Gianluca;Vaina, Lucia M.
几项已发表的单例研究揭示了单独的纹状外皮层视觉区域的脑损伤对由亮度差异（一阶运动）定义的全局视觉运动感知与由对比度差异定义的运动（二阶运动）的感知之间的双重分离。特别是，内侧纹状外皮质区域 V2/V3 似乎对于一阶运动的感知至关重要，但对于二阶运动则不然，而靠近颞顶枕交界处的皮质外侧和更前部的部分（在人体运动区域 hV5/Mt(+) 的范围内）似乎仅对于二阶运动的感知至关重要。为了测试不同视觉区域针对不同类型运动的功能专门化的假设，我们在 V2/V3、V5/MT 或后顶叶皮层 (PPC) 区域单侧应用重复经颅磁刺激 (rTMS)，同时受试者执行 2AFC 任务，在对侧视野中显示一阶或二阶全局运动。结果显示，rTMS 相对于 V2/V3 或 MT/V5 对两种类型运动的破坏程度相当，而 rTMS 相对于 PPC 的影响很小或没有影响。结果表明，要么先前对神经系统患者的心理物理学结果不正确（极不可能），要么外侧区域和内侧区域直接相连（就像在猕猴中一样），因此刺激一个区域会自动影响另一个区域，在这种情况下是破坏性的。
Several published single case studies reveal a double dissociation between the effects of brain damage in separate extra-striate cortical visual areas on the perception of global visual motion defined by a difference in luminance (first-order motion) versus motion defined by a difference in contrast (second-order motion). In particular, the medial extrastriate cortical region V2/V3 seems to be crucial for the perception of first-order motion, but not for second-order, whereas a lateral and more anterior portion of the cortex close to the temporo-parieto-occipital junction (in the territory of the human motion area hV5/Mt(+)) seems to be essential only for the perception of second-order motion. In order to test the hypothesis of a functional specialization of different visual areas for different types of motion, we applied repetitive transcranial magnetic stimulation (rTMS) unilaterally over areas V2/V3, V5/MT, or posterior parietal cortex (PPC) while subjects performed a 2AFC task with first- or second-order global motion displays in the contralateral visual field. Results showed a comparable disruption of the two types of motion, with both rTMS over V2/V3 or over MT/V5, and little or no effect with rTMS over PPC. The results suggest that either the previous psychophysical results with neurological patients are incorrect (highly unlikely) or that the lateral and medial regions are directly connected (as they are in macaque monkeys) such that stimulating one automatically affects the other, in this instance disruptively.