Fluctuations of fMRI activation patterns in visual object priming

Prior information shapes how the brain processes sensory inputs (e.g., priming effects). Recent studies of "behavioral oscillation” have demonstrated that the effects of visual object primes are temporally coordinated in the theta band to guide perception efficiently. However, the neural mechanism underlying this dynamic processing remains unclear. Here, we combine functional magnetic resonance imaging (fMRI) and a time-resolved paradigm to access high-temporal-resolution profiles of brain activation fluctuations corresponding to "behavioral oscillation" in visual object priming. Specifically, multivoxel activity patterns in the fusiform face area (FFA) and the parahippocampal place area (PPA) show temporal fluctuations in the theta band (~ 5 Hz). Importantly, the theta-band power in the FFA negatively correlates with reaction time, further indicating the critical role of the observed fluctuations in brain activation. By finely mapping the temporal dynamics of cortical responses, our fMRI results demonstrate that category-selective brain areas underlie the rhythmic coordination of visual object processing.

Fluctuations of fMRI activation patterns reveal theta-band dynamics of visual object priming

ABSTRACTThe brain dynamically creates predictions about upcoming stimuli to guide perception efficiently. Recent behavioral results suggest theta-band oscillations contribute to this prediction process, however litter is known about the underlying neural mechanism. Here, we combine fMRI and a time-resolved psychophysical paradigm to access fine temporal-scale profiles of the fluctuations of brain activation patterns corresponding to visual object priming. Specifically, multi-voxel activity patterns in the fusiform face area (FFA) and the parahippocampal place area (PPA) show temporal fluctuations at a theta-band (~5 Hz) rhythm. Importantly, the theta-band power in the FFA negatively correlates with reaction time, further indicating the critical role of the observed cortical theta oscillations. Moreover, alpha-band (~10 Hz) shows a dissociated spatial distribution, mainly linked to the occipital cortex. These findings, to our knowledge, are the first fMRI study that indicates temporal fluctuations of multi-voxel activity patterns and that demonstrates theta and alpha rhythms in relevant brain areas.