References of "Peters, Judith"
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See detailFrom coarse to fine? Spatial and temporal dynamics of cortical face processing
Goffaux, Valerie; Peters, Judith; Haubrechts, Julie et al

in Cerebral Cortex (2011), 21(2), 467-476

Primary vision segregates information along 2 main dimensions: orientation and spatial frequency (SF). An important question is how this primary visual information is integrated to support high level ... [more ▼]

Primary vision segregates information along 2 main dimensions: orientation and spatial frequency (SF). An important question is how this primary visual information is integrated to support high level representations. It is generally assumed that the information carried by different SF is combined following a coarse-to-fine sequence. We directly addressed this assumption by investigating how the network of face-preferring cortical regions processes distinct SF over time. Face stimuli were flashed during 75, 150, or 300 ms and masked. They were filtered to preserve low SF (LSF), middle SF (MSF), or high SF (HSF). Most face-preferring regions robustly responded to coarse LSF, face information in early stages of visual processing (i.e., until 75 ms of exposure duration). LSF processing decayed as a function of exposure duration (mostly until 150 ms). In contrast, the processing of fine HSF, face information became more robust over time in the bilateral fusiform face regions and in the right occipital face area. The present evidence suggests the coarse-to-fine strategy as a plausible modus operandi in high level visual cortex. [less ▲]

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See detailTemporal dynamics of face spatial frequency processing: An fmri masking experiment
Goffaux, Valerie; Peters, Judith; Schiltz, Christine UL et al

Poster (2009, May)

When processing a face stimulus, the human visual system tends to strongly integrate its constituent features (eyes, nose, mouth, etc) in a so-called holistic representation. Such feature integration ... [more ▼]

When processing a face stimulus, the human visual system tends to strongly integrate its constituent features (eyes, nose, mouth, etc) in a so-called holistic representation. Such feature integration mainly occurs in face-sensitive regions located in bilateral fusiform gyrii. Behavioural studies showed that feature integration relies on the extraction of low spatial frequencies (LSF) while high SF (HSF) underlie more local aspects of feature analysis. Following coarse-to-fine models of vision, we propose that the LSF-driven feature integration is an early and fast stage of face perception, in contrast to the longer-lasting extraction of detailed feature cues in HSF. By means of an event-related fMRI design, the present study investigated the temporal dynamics of face LSF and HSF processing in the network of face-sensitive cortical regions. Faces were flashed at 75, 150, or 300 msec, followed by a Gaussian mask. They were band-pass filtered to preserve low or high SF. At short stimulus durations, face-sensitive regions located in bilateral fusiform gyrii and superior temporal sulci responded more strongly to LSF than HSF faces. At longer durations, the same regions were more active for HSF than LSF faces. This pattern did not replicate for phase-scrambled versions of the stimuli. Taken together our findings suggest that face perception proceeds following a coarse-to-fine scenario, with an early and fast LSF-driven feature integration being relayed by the slower accumulation of HSF local information. [less ▲]

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