Burton H, Sinclair R J
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Somatosens Mot Res. 2000;17(3):213-28. doi: 10.1080/08990220050117574.
Neuronal responses in somatosensory cortical areas 3b and 1-2 (S1) were recorded during an attention task involving cue directed selection of one of three simultaneous stimuli: dual sinewave shaped vibrotactile stimuli applied to mirror sites on both hands or a similarly timed auditory tone. The cued stimulus occurred with one of two equally probable patterns: a constant amplitude vibration or the latter with a superimposed brief sinewave amplitude pulse midway during stimulation. Uncued stimuli always contained amplitude pulses. Two monkeys signaled the absence or presence of an amplitude pulse by appropriately moving a foot pedal up or down. Cues initiated trials by marking the location where the monkey had to discriminate the stimulus pattern. Cue location and stimulus pattern varied randomly per trial. Approximately 50% of cells (44/77 in 3b and 39/77 in 1-2) had significantly different firing rates to stimulation cued to the contralateral hand relative to spatially cuing the ipsilateral hand or cross-modally the auditory stimulus. Relatively suppressed firing rates during times prior to the epoch containing amplitude pulses improved signal-to-noise ratios for responses to amplitude pulses. Instances of significant enhanced activity during and after intervals with amplitude pulses were rare and relative to suppressed activity when cues directed attention to the ipsilateral hand or auditory stimulus. The present findings suggest that attention influences even the earliest stage somatosensory cortical processing. Findings were more modest in S1 than those previously seen in S2 (Burton et al., Somatosens Mot Res 14: 237-267, 1997), which supports the concept of multistage attention processes for touch.
在一项注意力任务中，记录了体感皮层3b区和1 - 2区（S1）的神经元反应。该任务涉及线索引导下从三个同时出现的刺激中选择其一：分别施加于双手镜像部位的双正弦波形状的振动触觉刺激，或时间同步的听觉音调。线索提示的刺激以两种等概率模式之一出现：恒定振幅振动，或在刺激过程中间叠加一个短暂正弦波振幅脉冲的振动。未被提示的刺激总是包含振幅脉冲。两只猴子通过适当上下移动脚踏板来表明振幅脉冲的有无。线索通过标记猴子必须辨别刺激模式的位置来启动试验。线索位置和刺激模式在每次试验中随机变化。相对于空间提示同侧手或跨模态提示听觉刺激，约50%的细胞（3b区44/77，1 - 2区39/77）对提示对侧手的刺激有显著不同的放电率。在包含振幅脉冲的时段之前，放电率相对抑制，这提高了对振幅脉冲反应的信噪比。在有振幅脉冲的间隔期间及之后，显著增强活动的情况很少，且相对于提示同侧手或听觉刺激时的抑制活动而言。本研究结果表明，注意力甚至会影响体感皮层处理过程的最早阶段。在S1区的发现比之前在S2区所见的更为适度（Burton等人，《体感与运动研究》14：237 - 267，1997），这支持了触觉多阶段注意力过程的概念。
