Abstract
Predictive coding theories of perception suggest the importance of constantly updated internal models of the world in predicting future sensory inputs. One implication of such models is that cortical regions whose function is to resolve particular stimulus attributes should also signal prediction violations with respect to those same stimulus attributes. Previously, through carefully designed experiments, we have demonstrated early-mid latency EEG/MEG prediction-error signals in the dorsal visual stream to violated expectations about stimulus orientation/trajectory, with localisations consistent with cortical areas processing motion and orientation. Here we extend those methods to simultaneously investigate the predictive processes in both dorsal and ventral visual streams. In this MEG study we employed a contextual trajectory paradigm that builds expectations using a series of image presentations. We created expectations about both face orientation and identity, either of which can subsequently be violated. Crucially this paradigm allows us to parametrically test double dissociations between these different types of violations. The study identified double dissociations across the type of violation in the dorsal and ventral visual streams, such that the right fusiform gyrus showed greater evidence of prediction-error signals to Identity violations than to Orientation violations, whereas the left angular gyrus and postcentral gyrus showed the opposite pattern of results. Our results suggest comparable processes for error checking and context updating in high-level expectations instantiated across both perceptual streams. Perceptual prediction-error signalling is initiated in regions associated with the processing of different stimulus properties.
Significance Statement Visual processing occurs along ‘what’ and ‘where’ information streams that run, respectively along the ventral and dorsal surface of the posterior brain. Predictive coding models of perception imply prediction-error detection processes that are instantiated at the level where particular stimulus attributes are parsed. This implies that, for instance, when considering face stimuli, signals arising through violated expectations about the person identity of the stimulus should localise to the ventral stream, whereas signals arising through violated expectations about head orientation should localise to the dorsal stream. We test this in a magnetoencephalography source localisation study. The analysis confirmed that prediction-error signals to identity versus head-orientation occur with similar latency, but activate doubly-dissociated brain regions along ventral and dorsal processing streams.
Acknowledgements
We acknowledge the Australian National Imaging Facility for the financial support of W.W. and the MEG system at Swinburne University of Technology. We gratefully acknowledge the gentle encouragement of the Oily Rag Foundation (EN10005). We’d also like to thank Jessica Guy, Deborah Loats and the rest of the SUT Babylab team for their involvement in data collection.
Author Contribution
J. E. R. and P. J. J. conceived the study, designed the study, and led writing of the manuscript. W. W. analysed the MEG data. S.L. and J. K. assisted in conception of the study and acquired the data. M. B. and A. W. Y. advised on the study design, data interpretation and writing up of the manuscript.
Footnotes
Conflict of Interest: The authors declare no competing financial interests, in accordance with JNeurosci’s Policy on Conflict of Interest.
