The Occipital Face Area Is Causally Involved in Facial Viewpoint Perception

Abstract

Humans reliably recognize faces across a range of viewpoints, but the neural substrates supporting this ability remain unclear. Recent work suggests that neural selectivity to mirror-symmetric viewpoints of faces, found across a large network of visual areas, may constitute a key computational step in achieving full viewpoint invariance. In this study, we used repetitive transcranial magnetic stimulation (rTMS) to test the hypothesis that the occipital face area (OFA), putatively a key node in the face network, plays a causal role in face viewpoint symmetry perception. Each participant underwent both offline rTMS to the right OFA and sham stimulation, preceding blocks of behavioral trials. After each stimulation period, the participant performed one of two behavioral tasks involving presentation of faces in the peripheral visual field: (1) judging the viewpoint symmetry; or (2) judging the angular rotation. rTMS applied to the right OFA significantly impaired performance in both tasks when stimuli were presented in the contralateral, left visual field. Interestingly, however, rTMS had a differential effect on the two tasks performed ipsilaterally. Although viewpoint symmetry judgments were significantly disrupted, we observed no effect on the angle judgment task. This interaction, caused by ipsilateral rTMS, provides support for models emphasizing the role of interhemispheric crosstalk in the formation of viewpoint-invariant face perception.

An fMRI study of visual hemifield integration and cerebral lateralization

“…While the VWFA result is consistent with existing models and experimental findings (Cohen et al, 2003; Molko et al, 2002), including finding from fMRI repetition suppression (Glezer, Jiang, & Riesenhuber, 2009), our observation of the same effect in the OWFA suggests that inter-hemifield integration of word form information occurs outside of the VWFA, and possibly during an earlier pre-lexical stage of shape processing than predicted by existing models of whole-word representation in the visual system. Interestingly, a similar proposal has been offered recently to explain right-lateralized face processing (Frässle et al, 2016), which exhibits striking parallels with word recognition (Behrmann & Plaut, 2013; Dehaene et al, 2015; Dundas, Plaut, & Behrmann, 2012), especially with respect to symmetry processing (Bona et al, 2015; Kietzmann et al, 2015), which may have a parallel in the OWFA for “symmetry breaking” in visual word form processing (possibly in addition to the VWFA; Pegado, Nakamura, Cohen, & Dehaene, 2011). Furthermore, given that defective callosal transfer and inter-hemispheric coordination is associated with dyslexia (Fabbro et al, 2001; Henderson et al, 2007), our findings highlight the possibility that at least some cases of dyslexia may be the result of impaired inter-hemifield integration (Kelly, Jones, McDonald, & Shillcock, 2004).…”

“…The OFA is typically larger and more frequently found in the right hemisphere (Pitcher, Walsh, & Duchaine, 2011), and it represents visual features of faces and spatial relations between them during the early stages of processing (Liu, Harris, & Kanwisher, 2010; Pitcher, Walsh, Yovel, & Duchaine, 2007; Rhodes, Michie, Hughes, & Byatt, 2009; Strother et al, 2011). The right OFA is distinct from its more elusive left counterpart in its sensitivity to mirror and its role in interhemispheric integration during face recognition (Bona, Cattaneo, & Silvanto, 2015; Frässle et al, 2016; Kietzmann et al, 2015). …”

Manifold decoding for neural representations of face viewpoint and gaze direction using magnetoencephalographic data

“…We also observed a gaze representation in the right STS that were discriminative of differences in gaze direction. These findings are consistent with those of previous studies Axelrod & Yovel, 2012;Duchaine & Yovel, 2015;Haxby et al, 2000;Kietzmann et al, 2012Kietzmann et al, , 2015.…”

“…Analysis involved comparing differences in the amplitude of brain responses and/or the use of multi-voxel pattern analysis (MVPA) to reveal the mechanisms underlying the processing of face-related data by the human brain. Experiment results reported by (Allison, Puce, & McCarthy, 2000;Axelrod & Yovel, 2012;Haxby et al, 2000;Kietzmann et al, 2012Kietzmann et al, , 2015 indicate that the inferior occipital gyri or occipital face area (OFA) is involved in the early perception of face viewpoint, whereas the superior temporal sulcus (STS) deals with movements in the eyes and mouth. Investigations into the temporal stages of face perception using EEG/MEG have indicated that the N170/M170 component is an event-related potential/field, which occurs approximately 170 ms after the stimulus onset and appears to originate in the fusiform face area (FFA) or STS (Deffke et al, 2007;Duchaine & Yovel, 2015;Nguyen & Cunnington, 2014;Sadeh, Podlipsky, Zhdanov, & Yovel, 2010).…”

Face Processing and TMS

“…Several TMS studies have demonstrated how the OFA is causally engaged in processing low level facial features. For example, Kietzmann et al (2015) demonstrated that TMS delivered over the right OFA impaired judgments of viewpoint angle when faces were presented in the contralateral (but not the ipsilateral) visual field. The same study also demonstrated that TMS delivered over the right OFA impaired judgements of facial viewpoint symmetry in both visual fields.…”