The brain is thought to generate internal predictions to optimize behaviour. However, it is unclear whether predictions signalling is an automatic brain function or depends on task demands. Here, we manipulated the spatial/temporal predictability of visual targets, and the relevance of spatial/temporal information provided by auditory cues. We used magnetoencephalography (MEG) to measure participants’ brain activity during task performance. Task relevance modulated the influence of predictions on behaviour: spatial/temporal predictability improved spatial/temporal discrimination accuracy, but not vice versa. To explain these effects, we used behavioural responses to estimate subjective predictions under an ideal-observer model. Model-based time-series of predictions and prediction errors (PEs) were associated with dissociable neural responses: predictions correlated with cue-induced beta-band activity in auditory regions and alpha-band activity in visual regions, while stimulus-bound PEs correlated with gamma-band activity in posterior regions. Crucially, task relevance modulated these spectral correlates, suggesting that current goals influence PE and prediction signalling.

人们认为大脑会产生内部预测以优化行为。但是，尚不清楚预测信号是自动的大脑功能还是取决于任务需求。在这里，我们操纵了视觉目标的时空可预测性，以及听觉提示所提供的时空信息的相关性。我们使用脑磁图（MEG）来衡量任务执行过程中参与者的大脑活动。任务相关性调节了预测对行为的影响：空间/时间可预测性提高了空间/时间判别的准确性，但反之则不然。为了解释这些影响，我们使用行为反应来估计理想观察者模型下的主观预测。基于模型的预测和预测错误（PE）的时间序列与可分离的神经反应相关：预测与提示引起的听觉区域的β波段活动和视觉区域的α波段活动相关，而刺激结合的PE与后部区域的γ波段活动相关。至关重要的是，任务相关性调制了这些频谱相关性，表明当前目标会影响PE和预测信号。