Department of Physiology, McGill University, Montreal, QC, Canada.
Cognitive Neuroscience Laboratory, German Primate Centre - Leibniz Institute for Primate Research, Göttingen, Germany.
Eur J Neurosci. 2017 Dec;46(12):2844-2858. doi: 10.1111/ejn.13764.
Single-cell studies in macaques have shown that attending to one of two stimuli, positioned inside a visual neuron's receptive field (RF), modulates the neuron's response to reflect the features of the attended stimulus. Such a modulation has been described as a 'push-pull' effect relative to a reference response: a neuron's response increases when attention is directed to a preferred stimulus, and decreases when attention is directed to a non-preferred stimulus. It has been further suggested that the response increase when attending to a preferred stimulus is the predominant effect. Here, we show that the observed attentional modulation depends on the reference response. We recorded neuronal responses in motion processing area middle temporal (MT) of macaques to two moving random dot patterns positioned inside neurons' RF. One pattern always moved in the neuron's antipreferred direction (null pattern), while the other moved in one of 12 directions (tuning pattern). At the beginning of a trial, a cue indicated the location and direction of the target. The animal was required to release a lever when a change in the target direction occurred, and to ignore changes in the distracter. Relative to neurons' initial responses to the dual stimuli (when attention was less likely to modulate responses), attending to the tuning pattern did not significantly modulate responses over time. However, attending to the null pattern progressively decreased responses over time. These results were quantitatively described by filter and input gain models, characterising a predominant response suppression relative to a reference response, rather than response enhancement.
在猕猴的单细胞研究中表明，当注意到两个刺激中的一个时，这两个刺激位于视觉神经元的感受野（RF）内，会调节神经元的反应，以反映被注意刺激的特征。这种调制被描述为相对于参考响应的“推挽”效应：当注意力指向偏好刺激时，神经元的反应增加，而当注意力指向非偏好刺激时，反应减少。进一步表明，当注意偏好刺激时，反应增加是主要效应。在这里，我们表明观察到的注意力调制取决于参考响应。我们记录了猕猴运动处理区中颞（MT）的神经元对两个位于神经元 RF 内的移动随机点模式的反应。一个模式总是朝着神经元的反偏好方向移动（零模式），而另一个模式朝着 12 个方向之一移动（调谐模式）。在试验开始时，提示指示目标的位置和方向。当目标方向发生变化时，动物需要释放杠杆，并忽略干扰器的变化。相对于神经元对双刺激的初始反应（当注意力不太可能调节反应时），随着时间的推移，注意调谐模式并没有显著调节反应。然而，注意零模式会随着时间的推移逐渐降低反应。这些结果通过滤波器和输入增益模型进行了定量描述，该模型描述了相对于参考响应的主要反应抑制，而不是反应增强。
