Neural substrates of evidence accumulation have been a central issue in decision-making studies because of the prominent success of the accumulation model in explaining a wide range of perceptual decision making. Since accumulation-shaped activities have been found in multiple brain regions, which are called accumulators, questions regarding functional relations among these accumulators are emerging. This study employed the deconvolution method of functional magnetic resonance imaging (fMRI) signals from human male and female participants during object-category decision tasks, taking advantage of the whole-brain coverage of fMRI with improved availability of temporal information of the deconvolved activity. We detected the accumulation activity in many non-category-selective regions (NCSRs) over the frontal, parietal, and temporal lobes as well as category-selective regions (CSRs) of the categorization task. Importantly, the frontal regions mostly showed activity peaks matching the decision timing (classified as "type-A accumulator"), while activity peaks of the parietal and temporal regions were behind the decision (classified as "type-B accumulator"). The CSRs showed activity peaks whose timing depended on both region and stimulus preference, plausibly reflecting the competition among the alternative choices (classified as "type-C accumulator"). The results suggest that these functionally heterogeneous accumulators form a system for evidence accumulation in which the type-A accumulator regions make decisions in a general manner while the type-B and type-C accumulator regions are employed depending on the modality and content of decision tasks. The concept of the accumulation system may provide a key to understanding the universality of the accumulation model over various kinds of decision tasks.

SIGNIFICANCE STATEMENT Perceptual decision making, such as deciding to walk or stop on seeing the signal colors, has been explained theoretically by the accumulation model, in which sensory information is accumulated to reach a certain threshold for making decisions. Neural substrates of this model, however, are still under elucidation among candidate regions found over the brain. We show here that, taking advantage of the whole-brain coverage of functional magnetic resonance imaging (fMRI) with improving availability of temporal information by deconvolution method, the accumulation is conducted by a system comprising many regions in different abstraction levels and only a part of these regions in the frontal cortex make decisions. The system concept may provide a key to explaining the universality of the accumulation model.

证据积累的神经基础一直是决策研究的核心问题，因为积累模型在解释广泛的感知决策方面取得了显著成功。由于在称为累加器的多个大脑区域中发现了累加型活动，因此出现了有关这些累加器之间功能关系的问题。本研究在对象类别决策任务期间采用来自人类男性和女性参与者的功能性磁共振成像 (fMRI) 信号的反卷积方法，利用 fMRI 的全脑覆盖，提高反卷积活动的时间信息的可用性。我们检测到额叶、顶叶、和颞叶以及分类任务的类别选择区域（CSR）。重要的是，额叶区域大多表现出与决策时间相匹配的活动峰值（归类为“A型蓄能器”），而顶叶和颞叶区域的活动峰值落后于决策（归类为“B型蓄能器”）。CSR 显示活动峰值，其时间取决于区域和刺激偏好，合理地反映了替代选择之间的竞争（归类为“C 型累加器”）。结果表明，这些功能异质的累加器形成了一个证据积累系统，其中 A 型累加器区域以一般方式做出决策，而 B 型和 C 型累加器区域根据决策任务的模态和内容进行使用. 累积系统的概念可以为理解累积模型在各种决策任务中的普遍性提供关键。

重要性声明感知决策，例如在看到信号颜色时决定走路或停下来，已经通过累积模型进行了理论上的解释，在该模型中，感觉信息被累积到一定的阈值以做出决策。然而，该模型的神经基质仍在大脑上发现的候选区域中的阐明中。我们在这里表明，利用功能磁共振成像 (fMRI) 的全脑覆盖以及通过反卷积方法提高时间信息的可用性，累积是由一个包含许多不同抽象级别的区域的系统进行的，并且只有一部分额叶皮层的这些区域做出决定。系统概念可能为解释积累模型的普遍性提供了一把钥匙。