Visual stimulation of saccades in magnetically tethered Drosophila
Visual stimulation of saccades in magnetically tethered Drosophila
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DOI：
10.1242/jeb.02369
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发表时间：
2006-08-15
影响因子：
2.8
通讯作者：
Dickinson, Michael H.
中科院分区：
文献类型：
--
作者：
Bender, John A.;Dickinson, Michael H.
会飞的果蝇--黑腹果蝇--会进行“身体跳跃”，即在大约70毫秒内改变方向约90秒。在自由飞行中，视觉扩张可以引起眼跳，而类似眼跳的转弯在被拴住的苍蝇身上也会被类似的刺激触发。然而，由于被严格拴住的苍蝇的虚构转弯遵循更长的时间进程，这两种行为在多大程度上共享一个共同的神经基础是未知的。系留飞行和自由飞行之间的一个关键区别是后者存在额外的感官线索，这可能有助于改变眼跳运动程序的时间进程。为了研究感觉反馈在扫视中的作用，我们开发了一种新的准备方法，将苍蝇拴在一个精细的钢销上，钢销在垂直方向的磁场中对齐，允许它绕偏航轴自由旋转。在这个实验范式中，苍蝇执行快速转弯的平均时间为35米80毫秒，类似于自由飞行眼跳的运动学。我们的结果表明，拴系飞行和自由飞行的眼跳具有共同的神经基础，但缺乏适当的反馈信号会扭曲严格固定的苍蝇的行为。使用我们的新范式，我们还研究了引发眼跳的视觉刺激的特征。我们的数据表明，当膨胀的物体达到临界阈值尺寸时，就会触发扫视，但它们的时间与扩张的准确时间进程几乎没有关系。这些结果与在其他昆虫中研究的扩展检测电路一致，但不排除基于局部运动检测器集成的其他模型。
Flying fruit flies, Drosophila melanogaster, perform 'body saccades', in which they change heading by about 90 in roughly 70 ms. In free flight, visual expansion can evoke saccades, and saccade-like turns are triggered by similar stimuli in tethered flies. However, because the fictive turns in rigidly tethered flies follow a much longer time course, the extent to which these two behaviors share a common neural basis is unknown. A key difference between tethered and free flight conditions is the presence of additional sensory cues in the latter, which might serve to modify the time course of the saccade motor program. To study the role of sensory feedback in saccades, we have developed a new preparation in which a fly is tethered to a fine steel pin that is aligned within a vertically oriented magnetic field, allowing it to rotate freely around its yaw axis. In this experimental paradigm, flies perform rapid turns averaging 35 m 80 ms, similar to the kinematics of free flight saccades. Our results indicate that tethered and free flight saccades share a common neural basis, but that the lack of appropriate feedback signals distorts the behavior performed by rigidly fixed flies. Using our new paradigm, we also investigated the features of visual stimuli that elicit saccades. Our data suggest that saccades are triggered when expanding objects reach a critical threshold size, but that their timing depends little on the precise time course of expansion. These results are consistent with expansion detection circuits studied in other insects, but do not exclude other models based on the integration of local movement detectors.