The present study attempts to explore the process by which knowledge of another's intentional behavior in a joint-action scenario is represented through the action observation and execution network-also known as the common coding system. Participants (n = 18) were instructed to perform the complementary social Simon task under the implemented belief of interaction with either an unseen human (biological agent) or a computer program, where in fact, all response sequences from either "partner" were generated by computer. Results provide behavioral and neurophysiological evidence (P3 and S-LRP) that the believed intentionality of another person's actions is sufficient to facilitate a strong-enough agency-dependent social Simon effect to modulate action planning and anticipation. We suggest that the co-representation of human action may be an evolved biologically tuned default of the human motor system.

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Temporal processing is crucial to many cognitive and motor functions. Comparing different aspects of temporal processing is important for a fundamental understanding of its neural mechanisms. In this study, the neural substrates activated during duration discrimination tasks across different sensory modalities, audition and vision, and sensory structures, empty and filled interval, were examined using event-related functional magnetic resonance imaging (MRI). The supplementary motor area and the basal ganglia are suggested as the common neural substrates for temporal processing across sensory modalities and sensory structures for explicit timing in the subsecond range.

By adulthood, literate humans have been exposed to millions of visual scenes and pages of text. Does the human visual system become attuned to the statistics of its inputs? Using functional magnetic resonance imaging, we examined whether the brain responses to line configurations are proportional to their natural-scene frequency. To further distinguish prior cortical competence from adaptation induced by learning to read, we manipulated whether the selected configurations formed letters and whether they were presented on the horizontal meridian, the familiar location where words usually appear, or on the vertical meridian. While no natural-scene frequency effect was observed, we observed letter-status and letter frequency effects on bilateral occipital activation, mainly for horizontal stimuli. The findings suggest a reorganization of the visual pathway resulting from reading acquisition under genetic and connectional constraints. Even early retinotopic areas showed a stronger response to letters than to rotated versions of the same shapes, suggesting an early visual tuning to large visual features such as letters.

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