NEURONAL-ACTIVITY IN THE SUPPLEMENTARY EYE FIELD DURING ACQUISITION OF CONDITIONAL OCULOMOTOR ASSOCIATIONS
NEURONAL-ACTIVITY IN THE SUPPLEMENTARY EYE FIELD DURING ACQUISITION OF CONDITIONAL OCULOMOTOR ASSOCIATIONS
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DOI：
10.1152/jn.1995.73.3.1101
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发表时间：
1995-03-01
影响因子：
2.5
通讯作者：
WISE, SP
中科院分区：
文献类型：
--
作者：
CHEN, LL;WISE, SP
1.补充眼野（SEF）被认为是一个前运动皮层举行的选择和控制扫视眼球运动。借鉴相邻的前运动皮层的研究，我们假设，如果SEF参与选择的行动的基础上任意的刺激反应协会，然后在SEF的任务相关的活动应该改变在这种协会的学习。恒河猴操作性条件反射，使扫视眼球运动到四个目标之一（7度上，下，左，右从中心），以响应中央凹指令刺激（IS）。对于每个IS，这四种可能的响应中有一种且只有一种被任意指定为“正确”。猴子对熟悉的IS做出反应，在整个训练和记录过程中保持不变的四种刺激，以及猴子以前没有见过的新IS。猴子最初通过试错来选择对新刺激的反应，表现水平接近偶然，但很快就学会了选择正确的扫视。我们研究了186个SEF细胞，因为猴子学习了新的视觉联想。神经元活动在四个任务期间被量化：在呈现IS期间，在指示的延迟期间（即，在去除IS之后但在触发或“走”刺激之前）、就在扫视之前、以及在扫视之后在目标位置的固定期间。每个任务期的出院率被认为是一个单独的病例进行分析，与IS之前的一个参考期进行比较，并从进一步分析中剔除ii无显著差异.我们观察到两个主要类别的活动变化在学习过程中，我们称之为学习选择性和学习依赖。学习选择性的情况下，表现出显着的进化活动的猴子学习眼跳是由一个新的IS指示，但没有显着的调制与熟悉的IS试验期间。这些细胞中的许多在与熟悉的IS的试验中几乎是不活跃的。然而，当用一种新的IS进行测试时，它们最初表现出戏剧性的调制。随着猴子选择正确的扫视（或目标）的可靠性增加，调制往往递减，直到细胞再次相对未调制，如在熟悉的IS试验中观察到的。这些细胞通常保持相对不活跃，直到猴子受到挑战，开始学习另一种新的刺激-反应关联。在所有的任务周期中都观察到了学习选择性活动，在186个充分测试的SEF细胞中，有33个（18%）在一个或多个任务周期中表现出学习选择性活动。学习依赖的情况下，类似于学习选择的，显着改变活动的学习过程中。学习依赖型病例与学习选择型病例在任务相关性调制中表现出差异。它们的活动在学习开始时通常是最低的，但随着试验的进行，它们的活动逐渐增加，这与猴子在选择正确反应方面的进步密切相关。在大多数情况下，新的IS试验的放电率收敛于那些熟悉的IS指示相同的眼跳，学习依赖的活动在所有的任务周期中观察到，和68（37%）的186个充分测试的SEF细胞显示出显着的学习依赖的活动在一个或多个任务周期。目前的研究结果支持的假设，SEF在选择的眼动或眼跳目标的基础上任意的刺激，并建议它可能是负责学习灵活的非空间刺激-反应关系的神经网络的一部分。
1. The supplementary eye field (SEF) has been viewed as a premotor cortical held for the selection and control of saccadic eye movements. Drawing on studies of the neighboring premotor cortex, we hypothesized that if the SEF participates in the selection of action based on arbitrary stimulus-response associations, then task-related activity in the SEF should change during the learning of such associations.2. Rhesus monkeys were operantly conditioned to make a saccadic eye movement to one of four targets (7 deg up, down, left, and right from center) in response to a foveal instruction stimulus (IS). One and only one of those four possible responses was arbitrarily designated ''correct'' for each IS. The monkeys responded to familiar ISs, four stimuli that remained unchanged throughout training and recording, as well as to novel ISs, which the monkeys had not previously seen. The monkeys initially chose responses to novel stimuli by trial and error, with near chance levels of performance, but quickly learned to select the correct saccade.3. We studied 186 SEF cells as monkeys learned new visuomotor associations. Neuronal activity was quantified in four task periods: during the presentation of the IS, during an instructed delay period (i.e., after the removal of the IS but before a trigger or ''go'' stimulus), just before the saccade, and after the saccade during fixation of the target location. The discharge rate in each task period was considered a separate case for analysis, compared with that in a reference period preceding the IS, and eliminated from Further analysis ii not significantly different.4. We observed two main categories of activity change during learning, which we termed learning selective and learning dependent. Learning-selective cases showed a significant evolution in activity as the monkeys learned which saccade was instructed by a novel IS, but had no significant modulation during trials with familiar ISs. Many of these cells were virtually inactive on trials with familiar ISs. However, they initially showed dramatic modulation when tested with a novel IS. As the monkey chose the correct saccade (or target) with increasing reliability, the modulation often decremented until the cell was again relatively unmodulated, as observed during familiar-IS trials. These cells usually remained relatively inactive until the monkeys were challenged to start learning another new stimulus-response association. Learning-selective activity was observed in all task periods, and 33 (18%) of the 186 adequately tested SEF cells showed learning-selective activity in one or more task periods.5. Learning-dependent cases, similar to learning-selective ones, significantly changed activity during the course of learning. Learning-dependent cases differed From learning-selective ones in showing task-related modulation for familiar-IS trials. Their activity was often lowest at the beginning of learning, but steadily incremented, trial by trial, in close correlation with the monkeys' improvement in selecting the correct response. In most costs, discharge rates on novel-IS trials converged on those for the familiar IS instructing the same saccade, Learning-dependent activity was observed in all task periods, and 68 (37%) of 186 adequately tested SEF cells showed significant learning-dependent activity in one or more task periods.6. The present findings support the hypothesis that SEF plays a role in the selection of eye movements or saccade targets on the basis of arbitrary stimuli and suggest that it may be part of a neural network responsible for learning flexible nonspatial stimulus-response relations.