Li Xiaobing, Basso Michele A
Department of Physiology, University of Wisconsin-Madison Medical School, Madison, Wisconsin 53706, USA.
J Neurosci. 2005 Dec 7;25(49):11357-73. doi: 10.1523/JNEUROSCI.3825-05.2005.
In addition to its role in saccade generation, the superior colliculus (SC) is involved in target selection, saccade selection, and shifting the focus of spatial attention. Here, we investigated the influence of saccade selection on sensory interactions within single response fields (RFs) of SC neurons. One or two differently shaped stimuli were presented within single RFs of SC neurons, and the shape of a centrally located cue indicated whether and where to make a saccade (Go-Go) or whether to make or withhold a saccade (Go/No-Go). We found that, when two stimuli appeared at different locations within a single RF, SC neuronal activity was reduced compared with when a single stimulus appeared in isolation within the center of the RF in both the Go-Go and Go/No-Go tasks. In both tasks, a subsequent cue indicating one stimulus as a saccade target reduced the influence of the second stimulus located within the RF. We found that the time course of the suppression resulting from the two stimuli was approximately 130 ms, a time close to that seen in cortex. Finally, we found that the influence of two stimuli within single RFs of SC neurons changed over time in both the Go-Go and the Go/No-Go tasks. Initially, the neurons averaged the influence of two stimuli. As the trial progressed, the SC neurons signaled only the saccade vector that was produced. We conclude that cues to shift gaze, like attention, modulate the influence of sensory interactions, providing additional support for the linkage between attention and saccade selection.
除了在扫视生成中发挥作用外，上丘（SC）还参与目标选择、扫视选择以及转移空间注意力焦点。在此，我们研究了扫视选择对SC神经元单个反应场（RF）内感觉交互作用的影响。在SC神经元的单个RF内呈现一个或两个形状不同的刺激，位于中央的线索形状表明是否以及在何处进行扫视（执行-执行），或者是否进行或抑制扫视（执行/不执行）。我们发现，当两个刺激出现在单个RF内的不同位置时，与在执行-执行和执行/不执行任务中单个刺激单独出现在RF中心时相比，SC神经元活动降低。在这两个任务中，随后将一个刺激指示为扫视目标的线索减少了位于RF内的第二个刺激的影响。我们发现，由两个刺激导致的抑制时间进程约为130毫秒，这一时间段与在皮层中观察到的相近。最后，我们发现，在执行-执行和执行/不执行任务中，SC神经元单个RF内两个刺激的影响会随时间变化。最初，神经元对两个刺激的影响进行平均。随着试验的进行，SC神经元仅发出所产生的扫视向量的信号。我们得出结论，像注意力一样，转移注视的线索会调节感觉交互作用的影响，为注意力与扫视选择之间的联系提供了额外支持。
