Yang Qing, Kapoula Zoï
Laboratoire de Physiologie de la Perception et de l'Action, UMR 7152, CNRS - Collège de France, 11, place Marcelin Berthelot, 75005 Paris, France.
Exp Brain Res. 2006 May;171(1):67-77. doi: 10.1007/s00221-005-0249-x. Epub 2005 Nov 24.
In real life we produce vertical saccades at different distances and eccentricities, and while our fixation is more or less actively engaged. The goal of this study is to examine vertical saccades in aged and young subjects, taking into consideration all these parameters. Eleven adults (20-28 years) and 11 aged subjects (63-83 years) were recruited. We used LED targets at 7.5 degrees or 15 degrees, up or down in four conditions: gap and overlap tasks, each done at two distances-at near (40 cm) and at far (150 cm). In the gap task fixation target extinguishes prior to target onset, while in the overlap condition it stays on after target onset; consequently, visual attention and fixation are employed differently in the two tasks. Eye movements were recorded with the Chronos video eye tracker. Results showed that vertical saccades were longer for aged subjects than for young adults under almost all conditions. For both aged and young subjects, latencies were shorter under the gap than under the overlap task. Latencies for eccentric targets at 15 degrees were significantly longer than those at 7.5 degrees but for aged subjects only; this effect was more pronounced for upward saccades under the overlap condition. Express type of latencies (80-120 ms) occurred frequently in the gap task and at similar rates for young adults (16%) and aged subjects (12%); in the overlap task express latencies were scarce in young adults (0.4%) and aged subjects (1.8%). Age deteriorates the ability to trigger regular volitional saccades but not the ability to produce express type of saccades. Latency increase with aging is attributed to the degeneration of central areas, e.g. oculomotor cortical areas involved in the initiation of vertical saccades.
在现实生活中，我们在不同距离和不同偏心率下产生垂直扫视，并且我们的注视或多或少处于积极参与状态。本研究的目的是考虑所有这些参数，对老年和年轻受试者的垂直扫视进行研究。招募了11名成年人（20 - 28岁）和11名老年受试者（63 - 83岁）。我们使用了位于7.5度或15度的LED目标，在四种情况下向上或向下移动：间隙任务和重叠任务，每种任务在两个距离下进行——近（40厘米）和远（150厘米）。在间隙任务中，注视目标在目标出现之前熄灭，而在重叠条件下，它在目标出现后仍然亮着；因此，在这两个任务中视觉注意力和注视的运用方式不同。使用Chronos视频眼动仪记录眼动。结果表明，在几乎所有条件下，老年受试者的垂直扫视都比年轻成年人更长。对于老年和年轻受试者，间隙任务下的潜伏期都比重叠任务下的短。15度偏心率目标的潜伏期明显长于7.5度目标的潜伏期，但仅在老年受试者中如此；这种效应在重叠条件下向上扫视时更为明显。快速类型的潜伏期（80 - 120毫秒）在间隙任务中频繁出现，年轻成年人（16%）和老年受试者（12%）的出现率相似；在重叠任务中，快速潜伏期在年轻成年人（0.4%）和老年受试者（1.8%）中很少见。年龄会削弱触发常规随意扫视的能力，但不会削弱产生快速类型扫视的能力。随着年龄增长潜伏期增加归因于中枢区域的退化，例如参与垂直扫视起始的动眼神经皮质区域。
