Abstract
Despite the importance of noticing visual changes, behavioral evidence shows that large changes often go undetected if they occur during visual field interruption, a phenomenon known as change blindness. Although a significant amount of behavioral research has investigated this topic, there is far less neuroimaging work and none using a saccade-contingent display change. This study utilized concurrent eye-tracking and fMRI to investigate the neural correlates of saccade-contingent global contrast change detection/blindness when viewing real-world photographs. Participants indicated whether they perceived a change after each trial. Two-thirds of trials were change trials and a staircase method was used to adjust the degree of contrast change to achieve approximately 50% detection. The change detection contrast (hit > miss) identified a well-defined, largely bilateral activation network (all t>6.45, p<.05 FWE) ranging from base feature detectors in the visual areas (cerebellum, V2, V3V) to ventral and dorsal processing stream activations and parietal attention-related areas (fusiform and lingual gyri, cuneus, putamen, insula, postcentral gyrus, intraparietal sulcus, inferior parietal lobule) to frontal/visuo-motor region activity (inferior and superior frontal gyri, supplementary eye fields), with marginally significant right-lateralized dorsolateral prefrontal cortex (DLPFC) activity. These results extend previous findings by highlighting the importance of bilateral activity and suggest that prior findings of robust DLPFC activation may have partly been due to dual task requirements. The change blindness contrast (miss > correct-rejection) revealed clear activation (all t>6.61, p<.05 FWE) in bilateral cuneus and fusiform and lingual gyri, but a distinct lack of fronto-parietal activity. Overall, these findings suggest that a largely bilateral ventral and dorsal fronto-parietal network is necessary for awareness of change. Thus, change blindness occurs when fronto-parietal activation related to attention is absent, despite notable neural activation that suggests detection without awareness.
Meeting abstract presented at VSS 2014