Human brain imaging has revealed that stimulus-induced activity does generally not simply add to the pre-stimulus activity, but rather builds in a non-additive way on this activity. Here we investigate this subject at the single neuron level and address the question whether and to what extent a strong form of non-additivity where activity drops post-cue is present in different areas of monkey cortex, including prefrontal and agranular frontal areas, during a perceptual decision making task involving action and tactic selection. Specifically we analyze spike train data recorded in vivo from the posterior dorsomedial prefrontal cortex (pmPFC), the supplementary motor area (SMA) and the presupplementary motor area (pre-SMA). For each neuron, we compute the ratio of the trial-averaged pre-stimulus spike count to the trial-averaged post-stimulus count. We also perform the ratio and averaging procedures in reverse order. We find that the statistics of these quantities behave differently across areas. pmPFC involved in tactic selection shows stronger non-additivity compared to the two other areas which more generically just increase their firing rate pos-stimulus. pmPFC behaved more similarly to pre-SMA, a likely consequence of the reciprocal connections between these areas. The trial-averaged ratio statistic was reproduced by a surrogate inhomogeneous Poisson process in which the measured trial-averaged firing rate for a given neuron is used as its time-dependent rate. Principal component analysis (PCA) of the trial-averaged firing rates of neuronal ensembles further reveals area-specific time courses of response to the stimulus, including latency to peak neural response, for the typical population activity. Our work demonstrates subtle forms of area-specific non-additivity based on the fine variability structure of pre- and post-stimulus spiking activity on the single neuron level. It also reveals significant differences between areas for PCA and surrogate analysis, complementing previous observations of regional differences based solely on post-stimulus responses. Moreover, we observe regional differences in non-additivity which are related to the monkey’s successful tactic selection and decision making.

人脑成像显示，刺激诱发的活动通常不会简单地添加到刺激前的活动中，而是以非累加方式建立在该活动上。在这里，我们在单个神经元水平上研究了这个主题，并解决了一个问题，在猴子皮层的不同区域，包括前额叶和颗粒状额叶区域，是否以及在多大程度上存在一种强烈的非加性形式，即在提示后活动下降。涉及行动和策略选择的感知决策任务。具体来说，我们分析了从后背内侧前额叶皮层 (pmPFC)、补充运动区 (SMA) 和补充前运动区 (pre-SMA) 记录的体内脉冲序列数据。对于每个神经元，我们计算试验平均刺激前尖峰计数与试验平均刺激后计数的比率。我们还以相反的顺序执行比率和平均程序。我们发现这些数量的统计数据在不同地区表现不同。与其他两个领域相比，参与策略选择的 pmPFC 表现出更强的非可加性，后者更一般地只是增加了刺激后的射击率。pmPFC 的行为与前 SMA 更相似，这可能是这些区域之间相互联系的结果。试验平均比率统计由代理非均匀泊松过程再现，其中测量的给定神经元的试验平均放电率用作其时间相关率。神经元集合的试验平均放电率的主成分分析 (PCA) 进一步揭示了对刺激反应的区域特异性时间过程，包括神经反应峰值的潜伏期，对于典型的人口活动。我们的工作展示了基于单个神经元水平上刺激前和刺激后尖峰活动的精细可变结构的区域特异性非可加性的微妙形式。它还揭示了 PCA 和替代分析区域之间的显着差异，补充了先前仅基于刺激后反应的区域差异观察结果。此外，我们观察到与猴子成功的策略选择和决策相关的非可加性的区域差异。补充先前仅基于刺激后反应的区域差异观察。此外，我们观察到与猴子成功的策略选择和决策相关的非可加性的区域差异。补充先前仅基于刺激后反应的区域差异观察。此外，我们观察到与猴子成功的策略选择和决策相关的非可加性的区域差异。