It is well established that the stimulus-preceding negativity (SPN) decreases in amplitude as a task is mastered, a phenomenon generally attributed to the reduction in anticipatory attention as feedback becomes less needed. Typically, the experiments supporting this assumption have used relatively short delays (<3 s). However, we found in a previous study that this decline in amplitude, although present during the 2.5-s prefeedback delay of a patterned key-pressing task, was absent with an 8-s delay. We reexamined this finding using a 6-s delay and found that the SPN diminished at frontal sites as participants learned a sequence of four keypress durations, but that this modulation was limited to the early half of the delay (maximum at 2 s). Decline of lateralized sensorimotor theta activity across trials was also limited to early portions of the delay. These findings suggest that processes other than anticipatory attention to feedback may be more relevant for explaining SPN diminution. Such processes could include adjustment and maintenance of action-outcome expectancies (e.g., forward models) during the prefeedback interval.

中文翻译：

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学习处理延迟结果：预反馈间隔期间的脑电图振荡和缓慢电位

众所周知，随着任务的掌握，刺激先于消极性 (SPN) 的幅度会降低，这种现象通常归因于预期注意力的减少，因为反馈变得不那么需要。通常，支持这一假设的实验使用了相对较短的延迟（<3 s）。然而，我们在之前的一项研究中发现，这种幅度下降虽然存在于模式按键任务的 2.5 秒预反馈延迟期间，但在 8 秒延迟时不存在。我们使用 6 秒的延迟重新检查了这一发现，发现当参与者学习一系列四个按键持续时间时，额叶部位的 SPN 减少了，但这种调制仅限于延迟的前半部分（最大为 2 秒）。试验中横向感觉运动θ活动的下降也仅限于延迟的早期部分。这些发现表明，除了对反馈的预期关注之外，其他过程可能与解释 SPN 减少更相关。这样的过程可能包括在预反馈间隔期间对行动结果预期（例如，前向模型）的调整和维护。