Gilmore Rick O, Hou C, Pettet M W, Norcia A M
Department of Psychology, The Pennsylvania State University, University Park, PA 16802, USA.
Vis Neurosci. 2007 Nov-Dec;24(6):845-56. doi: 10.1017/S0952523807070769.
Humans discriminate approaching objects from receding ones shortly after birth, and optic flow associated with self-motion may activate distinctive brain networks, including the human MT+ complex. We sought evidence for evoked brain activity that distinguished radial motion from other optic flow patterns, such as translation or rotation by recording steady-state visual evoked potentials (ssVEPs), in both adults and 4-6 month-old infants to direction-reversing optic flow patterns. In adults, radial flow evoked distinctive brain responses in both the time and frequency domains. Differences between expansion/contraction and both translation and rotation were especially strong in lateral channels (PO7 and PO8), and there was an asymmetry between responses to expansion and contraction. In contrast, infants' evoked response waveforms to all flow types were equivalent, and showed no evidence of the expansion/contraction asymmetry. Infants' responses were largest and most reliable for the translation patterns in which all dots moved in the same direction. This pattern of response is consistent with an account in which motion processing systems detecting locally uniform motion develop earlier than do systems specializing in complex, globally non-uniform patterns of motion, and with evidence suggesting that motion processing undergoes prolonged postnatal development.
人类在出生后不久就能区分接近的物体和后退的物体，与自身运动相关的光流可能会激活独特的脑网络，包括人类的MT+复合体。我们通过记录成人和4至6个月大婴儿对方向反转光流模式的稳态视觉诱发电位（ssVEP），寻找能将径向运动与其他光流模式（如平移或旋转）区分开来的诱发脑活动的证据。在成人中，径向流在时域和频域都诱发了独特的脑反应。在外侧通道（PO7和PO8）中，扩张/收缩与平移和旋转之间的差异尤为明显，并且对扩张和收缩的反应存在不对称性。相比之下，婴儿对所有流类型的诱发反应波形是相同的，没有显示出扩张/收缩不对称的证据。婴儿对所有点都朝同一方向移动的平移模式的反应最大且最可靠。这种反应模式与一种观点一致，即检测局部均匀运动的运动处理系统比专门处理复杂的、全局非均匀运动模式的系统发育更早，并且有证据表明运动处理在出生后会经历长时间的发育。
