皮质 LIP 区域的损伤仅在到达运动伴有扫视时才会影响到达运动的起始,这揭示了一个活跃的眼手协调回路。
Lesions of cortical area LIP affect reach onset only when the reach is accompanied by a saccade, revealing an active eye-hand coordination circuit.
机构信息
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
出版信息
Proc Natl Acad Sci U S A. 2013 Feb 5;110(6):2371-6. doi: 10.1073/pnas.1220508110. Epub 2013 Jan 22.
The circuits that drive visually guided eye and arm movements transform generic visual inputs into effector-specific motor commands. As part of the effort to elucidate these circuits, the primate lateral intraparietal area (LIP) has been interpreted as a priority map for saccades (oculomotor-specific) or a salience map of space (not effector-specific). It has also been proposed as a locus for eye-hand coordination. We reversibly inactivated LIP while monkeys performed memory-guided saccades and reaches. Coordinated saccade and reach reaction times were similarly impaired, consistent with a nonspecific role. However, reaches made without an accompanying saccade remained intact, and the relative temporal coupling of saccades and reaches was unchanged. These results suggest that LIP contributes to saccade planning but not to reach planning. Coordinated reaches are delayed as a result of an eye-hand coordination mechanism, located outside of LIP, that actively delays reaches until shortly after the onset of an associated saccade. We conclude with a discussion of how to reconcile specificity for saccades with a possible role in directing attention.
驱动视觉引导的眼睛和手臂运动的电路将通用视觉输入转换为特定于效应器的运动命令。作为阐明这些电路的努力的一部分,灵长类动物的外侧顶内区 (LIP) 被解释为扫视(眼球运动特异性)的优先映射或空间的显着性映射(非效应器特异性)。它也被提议作为眼手协调的位置。当猴子进行记忆引导的扫视和伸手时,我们可逆地失活了 LIP。协调的扫视和伸手反应时间都受到类似的损害,这与非特异性作用一致。然而,没有伴随扫视的伸手仍然完好无损,并且扫视和伸手的相对时间耦合保持不变。这些结果表明,LIP 有助于扫视计划,但不参与伸手计划。协调的伸手会延迟,原因是眼手协调机制位于 LIP 之外,该机制会主动延迟伸手,直到与关联扫视开始后不久。我们最后讨论了如何调和扫视的特异性与引导注意力的可能作用。