PRIMATE FRONTAL-CORTEX - NEURONAL-ACTIVITY FOLLOWING ATTENTIONAL VERSUS INTENTIONAL CUES
PRIMATE FRONTAL-CORTEX - NEURONAL-ACTIVITY FOLLOWING ATTENTIONAL VERSUS INTENTIONAL CUES
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DOI：
10.1007/bf00229650
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发表时间：
1993-07-01
影响因子：
2
通讯作者：
WISE, SP
中科院分区：
文献类型：
--
作者：
BOUSSAOUD, D;WISE, SP
我们研究了灵长类动物额叶皮层的三个部分的神经元活动：背侧（PMD）和腹侧（PMV）前运动皮层和腹外侧部分的背外侧前额叶（PF）皮层。两只猴子注视着视频显示器中心的一个0.2度的白色正方形，同时按下位于两个触摸板之间的开关。在每次试验中，首先呈现空间注意/记忆（SAM）线索。SAM提示由一个2度× 2度的正方形组成，通常是红色或绿色，其位置指示条件运动指令在延迟期后将出现的位置。包含运动指令的刺激事件，称为运动指令/条件（MIC）线索，可以有两种一般类型。它可能由一个2度× 2度的正方形刺激组成，与在该试验中与SAM提示相同的位置处呈现的SAM提示之一相同。当MIC提示是一个正方形时，它根据以下条件规则指示猴子将其前肢移动到两个触摸板中的一个：绿色MIC提示意味着与右侧触摸板的接触将在该试验中获得奖励，红色MIC提示指示移动到左侧触摸板。或者，MIC提示可能由两个2度x 2度的正方形组成，其中只有一个在SAM提示位置：在这些情况下，一个正方形是红色的，另一个是绿色。在该试验中，SAM提示位置的彩色方块是指示刺激，MIC提示的其他部分是无关紧要的。当经过一段可变的延迟时间后，MIC提示消失时，猴子必须在1秒内触摸适当的目标以获得奖励，并可以打破视觉固定。实验设计允许比较额叶皮层活动时，一个刺激，相同的retinocentric，craniocentric，allocentric空间位置以及所有其他刺激参数，有两个不同的含义的动物的行为。当刺激是SAM线索时，它导致空间注意力重新定位到它的位置，或者将它的位置存储在空间记忆中。相比之下，当它是MIC提示时，相同的刺激指示运动动作在延迟一段时间后执行。对于大多数的PMd神经元（55%），后MIC线索活动超过后SAM线索活动。在许多情况下，没有活动遵循SAM线索，虽然相同的刺激引起深刻的调制时，它作为MIC线索。相比之下，在PF中，显着较少的细胞（30%）表现出这样的属性，PMv在这方面的中间（36%）。结果支持这一假设，即许多PMd细胞反映了运动的刺激意义，并在PF细胞的比例显着较小。
We examined neuronal activity in three parts of the primate frontal cortex: the dorsal (PMd) and ventral (PMv) premotor cortex and a ventrolateral part of the dorsolateral prefrontal (PF) cortex. Two monkeys fixated a 0.2-degrees white square in the center of a video display while depressing a switch located between two touch pads. On each trial, a spatial-attentional/mnemonic (SAM) cue was presented first. The SAM cue consisted of one 2-degrees x 2-degrees square, usually red or green, and its location indicated where a conditional motor instruction would appear after a delay period. The stimulus event containing the motor instruction, termed the motor instructional/conditional (MIC) cue, could be of two general types. It might consist of a single 2-degrees x 2-degrees square stimulus identical to one of the SAM cues presented at the same location as the SAM cue on that trial. When the MIC cue was a single square, it instructed the monkey to move its forelimb to one of the two touch pads according to the following conditional rule: a green MIC cue meant that contact with the right touch pad would be rewarded on that trial and a red MIC cue instructed a movement to the left touch pad. Alternatively, the MIC cue might consist of two 2-degrees x 2-degrees squares, only one of which was at the SAM-cue location: in those cases, one square was red and the other was green. The colored square at the SAM cue location for that trial was the instructing stimulus, and the other part of the MIC cue was irrelevant. When, after a variable delay period, the MIC cue disappeared, the monkey had to touch the appropriate target within 1 s to receive a reward and could break visual fixation. The experimental design allowed comparison of frontal cortical activity when one stimulus, identical in retinocentric, craniocentric, and allocentric spatial location as well as all other stimulus parameters, had two different meanings for the animal's behavior. When a stimulus was the SAM cue, it led to either a reorientation of spatial attention to its location, or the storage of its location in spatial memory. By contrast, when it was the MIC cue, the same stimulus instructed a motor act to be executed after a delay period. For the majority of PMd neurons (55%), post-MIC cue activity exceeded post-SAM cue activity. In many instances, no activity followed the SAM cue, although the identical stimulus caused profound modulation when it served as the MIC cue. In PF, by contrast, significantly fewer cells (30%) showed such a property, and PMv was intermediate in this respect (36%). The results support the hypothesis that many PMd cells reflect the motor significance of stimuli, and that a significantly smaller proportion of cells in PF do so.