Converging evidence suggests that visual brain regions are part of a widespread network that signals forthcoming reward. However, the precise temporal dynamics underlying the interaction between reward and visual information processing remain unclear. To further investigate this issue, we used magnetoencephalography (MEG) in combination with two versions of a face/scene discrimination task followed by a recognition memory test. In experiment 1, the distinction between faces and scenes was associated with monetary reward prospect, whereas in experiment 2 subjects distinguished between both categories in the absence of reward. In both experiments characteristic neural category effects (i.e., differences between faces and scenes) were observed in the event-related magnetic fields (ERF) at ~100 ms (M100) and ~170 ms (M170) after stimulus onset. Importantly, both ERF components (M100 and M170) were amplified in the context of reward (i.e., experiment 1) and this interaction could be source localized to the lateral occipital cortex (~100 ms) and fusiform gyrus (~170 ms). Furthermore, neural effects of reward prediction emerged over frontal sensors at ~300 ms after stimulus onset which reliably correlated with subsequent recognition memory performance. These results demonstrate that reward motivation can modulate early neural computations of complex visual information, possibly by tuning sensory neurons within the visual cortex.
