畢業演講
Object recognition and selectivity rely heavily on the activation of neural representations for the objects in the human brain, enabling individuals to process and interact with external information within real-world environments. Previous studies have developed multivariate pattern analyses to investigate the functional mechanisms and neural representations underlying object recognition and selectivity in the human visual cortex. However, it remains unclear whether and how spatial and temporal information of object recognition and selectivity can be represented within the category-selective brain regions and integrated across different imaging modalities. In this work, we adopt the multivariate pattern analysis approach to investigate the spatiotemporal dynamics of neural representations for object recognition and selectivity. In Study I, our fMRI results using multivariate pattern analysis demonstrated the distinct and shared configural representations for the inversion effects for face and Chinese character recognition in category-selective and object-related brain areas. In Study II, we further tracked the temporal dynamics of the inversion-related neural responses for face and character recognition using MEG with the multivariate decoding approach. Through temporal generalization analysis, we decoded the neural information about stimulus orientation and category over and across time for faces and characters. In the final study, we examined the spatiotemporal profiles of the functional operations and the underlying mechanisms through the top-down modulation of attention on object selectivity in both face-selective and scene-selective brain regions using an fMRI-MEG fusion approach. The fusion results showed the attentional enhancement of representational similarity in category-selective brain areas. Importantly, we also observed that the goal-directed modulation of representational similarity in the category-selective brain areas was guided by the prefrontal cortex using the Granger causality analysis. Together, this work provides novel evidence improving our understanding of the spatiotemporal dynamics of neural representations for object recognition and selectivity in the human brain.