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Silvia Ubaldi, Aidas Aglinskas, Elisa Fait, Scott Fairhall; Temporal dynamics of the core and extended face perception system with fMRI. Journal of Vision 2017;17(10):264. doi: 10.1167/17.10.264.
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© ARVO (1962-2015); The Authors (2016-present)
The extensively studied core and extended network for perceiving and knowing about others provides for a critical aspect of human cognition. Here, to gain a systems-level understanding of hierarchical organization and interregional coordination, we apply a novel approach to assess temporal dynamics with fMRI. To determine the differential temporal-tuning of cortical regions, we cognitively overload the system using the rapid-serial presentation of faces (N=35 participants). Famous faces and buildings were presented at twelve different ISIs ranging from 100 to 1200 msec. Contrasting faces with buildings revealed the core system of face perception (OFA, FFA, pSTS), along with the extended system areas (precuneus, mPFC, IFG, ATL, amygdalae). Beta-values for each ISI were extracted to determine differential regional temporal-tuning across the system. Neural activity in OFA and FFA was maximal at ISI 300 msec, offsetting around 400 msec in OFA and at 500 msec in FFA. A similar temporal-tuning profile in IFG is consistent with top-down/perceptual coordination. In extended system areas (precuneus, ATL, mPFC), activity was effectively gated at faster ISI's, coming online only in a second wave of activations peaking at 500 msec. A more complex profile was observed in pSTS. Investigating cortical temporal-tuning provides novel insight into the systems-level organization network. In particular, convergent temporal profiles between IFG and core regions suggest a role of the IFG in top-down amplification of relevant/perceptual signals. We also observed a broad two-stage activation of the system, with early-perceptual processes transitioning to a near simultaneous second wave of activation across the extended system. Interestingly the amygdala, a potentially rapidly activated limbic region, grouped with these latter areas. The application of cognitive-masking to determine regional temporal tuning provides novel insight into the function of face-perception system while simultaneously providing a bridge between fMRI and magneto/encephalographic techniques.
Meeting abstract presented at VSS 2017
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