Salzman C D, Murasugi C M, Britten K H, Newsome W T
Department of Neurobiology, Stanford University School of Medicine, California 94305.
J Neurosci. 1992 Jun;12(6):2331-55. doi: 10.1523/JNEUROSCI.12-06-02331.1992.
Physiological and behavioral evidence suggests that the activity of direction selective neurons in visual cortex underlies the perception of moving visual stimuli. We tested this hypothesis by measuring the effects of cortical microstimulation on perceptual judgements of motion direction. To accomplish this, rhesus monkeys were trained to discriminate the direction of motion in a near-threshold, stochastic motion display. For each experiment, we positioned a microelectrode in the middle of a cluster of neurons that shared a common preferred direction of motion. The psychophysical task was then adjusted so that the visual display was presented directly over the neurons' receptive field. The monkeys were required to discriminate between motion shown either in the direction preferred by the neurons or in the opposite direction. On half the trials of an experiment, we applied electrical microstimulation while monkeys viewed the motion display. We hypothesized that enhancing the neurons' discharge rate would introduce a directionally specific signal into the cortex and thereby influence the monkeys' choices on the discrimination task. We compared the monkeys' performance on "stimulated" and "nonstimulated" trials in 139 experiments; all trials within an experiment were presented in random order. Statistically significant effects of microstimulation were obtained in 89 experiments. In 86 of the 89 experiments with significant effects (97%), the monkeys indicated that motion was in the neurons' preferred direction more frequently on stimulated trials than on nonstimulated trials. The data demonstrate a functional link between the activity of direction selective neurons and perceptual judgements of motion direction.
生理学和行为学证据表明，视觉皮层中方向选择性神经元的活动是移动视觉刺激感知的基础。我们通过测量皮层微刺激对运动方向感知判断的影响来验证这一假设。为实现这一点，对恒河猴进行训练，使其在接近阈值的随机运动显示中辨别运动方向。在每个实验中，我们将一个微电极放置在一群具有共同偏好运动方向的神经元集群中间。然后调整心理物理学任务，以便将视觉显示直接呈现在神经元的感受野上方。要求猴子辨别在神经元偏好方向或相反方向上显示的运动。在实验的一半试验中，当猴子观看运动显示时，我们施加电微刺激。我们假设提高神经元的放电率会将一个方向特异性信号引入皮层，从而影响猴子在辨别任务中的选择。我们在139个实验中比较了猴子在“刺激”和“非刺激”试验中的表现；实验中的所有试验均以随机顺序呈现。在89个实验中获得了微刺激的统计学显著效应。在89个有显著效应的实验中的86个（97%），猴子表明在刺激试验中比在非刺激试验中更频繁地指示运动在神经元的偏好方向上。数据证明了方向选择性神经元的活动与运动方向感知判断之间的功能联系。
