Abstract
The human brain must integrate information across the left and right hemispheres to construct a coherent representation of the perceptual world. Characterising how visual information from the left and right visual fields is represented in the two hemispheres can inform information transfer in the brain. Previous work on this topic has focused on the dynamics of neural activation but it has been difficult to determine what information is being encoded within each hemisphere. Here, we investigated information processing within each hemisphere and the degree to which the information is distinct or redundant across hemispheres. We presented participants (N = 20) with images of faces, words and other objects in rapid serial visual presentation sequences while their neural responses were measured using electroencephalography (EEG). Crucially, stimuli were presented either centrally or lateralised to the left and right visual fields. Participants performed an orthogonal colour change task on three dots that marked possible image positions. Multivariate pattern decoding methods were applied to the EEG data to assess the coding of object information in the brain, separately for electrode clusters over each hemisphere. As expected, stimulus information was more robust and emerged earlier in the contralateral hemisphere than the ipsilateral hemisphere. Interestingly, the temporal dynamics of information within the contra and ipsilateral hemispheres followed different trajectories. We further showed that representational structure aligned across the two hemispheres at approximately 200ms. These results provide new insights into the dynamics of object perception and the competitive versus cooperative nature of hemispheric processing.