Tehovnik Edward J, Slocum Warren M
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Bldg. 46-6041, Cambridge, MA 02139, USA.
Exp Brain Res. 2007 Jan;176(3):413-24. doi: 10.1007/s00221-006-0625-1. Epub 2006 Aug 1.
Electrical microstimulation of macaque striate cortex (area V1) delays the execution of saccadic eye movements made to a visual target placed in the receptive field of the stimulated neurons. The region of visual space within which saccades are delayed is called a delay field. We examined the effects of changing the parameters of stimulation and target size on the size of a delay field. Rhesus monkeys were required to generate a saccadic eye movement to a punctate and white visual target presented within or outside the receptive field of the neurons under study. On 50% of trials, a train of stimulation consisting of 0.2-ms anode-first pulses was delivered to the neurons before the onset of the visual target. Stimulations were performed in the operculum at 0.9-2.0 mm below the cortical surface. It was found that increases in current (50-100 microA), pulse frequency (100-300 Hz), or train duration (75-300 ms) increased the size of a delay field and increases in target size (0.1 degrees -0.2 degrees of visual angle) decreased the size of a delay field. Delay fields varied in size between 0.1 and 0.6 degrees of visual angle. These results are related to the properties of phosphenes induced by electrical stimulation of V1 in humans and compared to the interference effects observed following transcranial magnetic stimulation of human V1.
对猕猴纹状皮层（V1区）进行电微刺激会延迟对置于受刺激神经元感受野内的视觉目标做出的扫视眼动的执行。扫视被延迟的视觉空间区域称为延迟场。我们研究了改变刺激参数和目标大小对延迟场大小的影响。恒河猴需要对呈现于正在研究的神经元感受野内或外的点状白色视觉目标做出扫视眼动。在50%的试验中，在视觉目标出现之前，向神经元施加一串由0.2毫秒阳极先于阴极的脉冲组成的刺激。刺激在皮层表面以下0.9 - 2.0毫米的脑盖处进行。结果发现，电流（50 - 100微安）、脉冲频率（100 - 300赫兹）或串持续时间（75 - 300毫秒）的增加会增大延迟场的大小，而目标大小（视角0.1度 - 0.2度）的增加会减小延迟场的大小。延迟场的大小在视角0.1度至0.6度之间变化。这些结果与人类中电刺激V1区诱发的光幻视的特性相关，并与人类V1区经颅磁刺激后观察到的干扰效应进行了比较。
