References of "Goffaux, Valérie"
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See detailFacilitation and inhibition of return using numbers as attentional cues
Hoffmann, Danielle UL; Goffaux, Valérie; Schiltz, Christine UL

Poster (2011)

Behavioural studies have shown a relation between numbers and space (DeHevia et al., 2008). Fischer and colleagues (2003) showed that digits can act as central spatial cues in a target detection task ... [more ▼]

Behavioural studies have shown a relation between numbers and space (DeHevia et al., 2008). Fischer and colleagues (2003) showed that digits can act as central spatial cues in a target detection task, resulting in shorter reaction times (RT) for left-sided targets when preceded by small numbers and for right-sided targets when preceded by large numbers. This facilitation effect indicates that numbers orient visuo-spatial attention to the left or right hemifield, depending on their magnitude. To date no studies investigated whether this facilitation is followed by inhibition of return at longer intervals, as could be expected with visuo-spatial attention shifts. To this aim, we designed an analogous paradigm to Fischer et al.’s, introducing additional longer intervals. Participants (n=25) were presented a task irrelevant digit (1,2 vs. 8,9) for 400ms and had to detect a brief (100ms) lateral target appearing after a variable interval (100, 250, 500, 750, 1000, 1250ms). A 2x6 repeated measures ANOVA of mean RT, with congruency and interval as within-subject variables yielded a significant interaction (F(5,24)=2.3, p<0.05). As expected, targets were detected faster when appearing in the congruent (small-left, large-right) hemifield after 250ms. Using the regression method proposed by Lorch and Myers (1990), the slope at this interval was significantly negative (t(24)=1.70, p=0.05); indicating a facilitation for the detection of targets in the congruent hemifield) (cf. Fischer et al., 2003). At the 1250ms interval, targets were detected significantly slower when they appeared in the congruent compared to the incongruent hemifield (yielding significantly positive slopes at 1250ms: t(24)=2.68, p=0.007). These findings provide the first evidence that digits not only produce facilitation effects at shorter intervals, but also induce inhibitory effects at longer intervals, confirming the visuo-spatial nature of the attention shifts associated with Arabic digits. [less ▲]

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See detailAttentional shifts due to irrelevant numerical cues: Behavioral investigation of a lateralized target discrimination paradigm
Schiltz, Christine UL; Dormal, Giulia; Martin, Romain UL et al

in Journal of Vision (2010), 10(7),

Behavioural evidence indicates the existence of a link between numerical representations and visuo-spatial processes. A striking demonstration of this link was provided by Fischer and colleagues (2003 ... [more ▼]

Behavioural evidence indicates the existence of a link between numerical representations and visuo-spatial processes. A striking demonstration of this link was provided by Fischer and colleagues (2003), who reported that participants detect a target more rapidly in the left hemifield, if it is preceded by a small number (e.g. 2 or 3) and more rapidly in the right hemifield if preceded by a large number (e.g. 8 or 9). This is strong evidence that numbers orient visuo-spatial attention to different visual hemifields (e.g., left and right) depending on their magnitude (e.g., small and large, respectively). Here, we sought to replicate number-related attentional shifts using a discrimination task. The participants (n=16) were presented 1 digit (1,2 vs. 8,9) at the centre of the screen for 400ms. After 500ms, 1000ms or 2000ms, a target was briefly flashed in either the right or left hemifield and participants had to report its colour (red or green). They were told that the central digit was irrelevant to the task. We hypothesized that the attentional shift induced by the centrally presented numbers should induce congruency effects for the target discrimination task, so that small (or large) numbers would facilitate the processing of left (or right) targets. Our results confirmed this prediction, but only for the shortest digit-target interval (500ms). This is supported by a significant interaction between number magnitude (small/large) and target hemifield (left/right). The link between numerical and spatial representations further predicts a positive relation between number magnitude and the difference in RT between left and right targets. Regression slopes were computed individually and a positive slope was obtained for short number-target interval. These findings indicate that the attentional shifts induced by irrelevant numerical material are independent of the exact nature of target processing (discrimination vs. detection). [less ▲]

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See detailWhen small is left and large is right : Behavioural evidence for attentional shifts due to irrelevant numerical cues
Hoffmann, Danielle UL; Goffaux, Valérie; Schiltz, Christine UL

Poster (2010)

Numerous behavioural studies indicate the existence of a link between numerical representations and visuo-spatial processes (for review see DeHevia et al., 2008). A striking demonstration of this link was ... [more ▼]

Numerous behavioural studies indicate the existence of a link between numerical representations and visuo-spatial processes (for review see DeHevia et al., 2008). A striking demonstration of this link was provided by Fischer and colleagues (2003), who reported that participants detect a target faster in the left hemifield, if preceded by a small number (e.g. 2 or 3) and faster in the right hemifield if preceded by a large number (e.g. 8 or 9). This is strong evidence that numbers orient visuo-spatial attention to the left or right hemifield, depending on their magnitude (e.g., small and large, respectively) (see also Galfano et al., 2006; Ristic et al., 2006). We designed a modified version of this target detection paradigm, by replacing the detection task with a target discrimination task (cf. Hommel et al., 2001). The participants (n=16) were presented 1 task irrelevant digit (1,2 vs. 8,9) for 400ms. After a variable inter-stimulus interval (500, 1000 or 2000ms), they had to discriminate the colour of a brief (100ms) lateral target. We hypothesized that the centrally presented numbers would induce an orientation of attention, in the same direction as the initial observations by Fischer et al. (2003). The current results indicate a significant effect, but only for the shortest digit-target interval (500ms). We observed a significant interaction between number magnitude (small/large) and side of target presentation (left/right) (F1,15 =7.784, p<0.014). These findings indicate that the attentional shifts induced by irrelevant numerical material are independent of the exact nature of target processing (discrimination vs. detection). [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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See detailFace inversion disrupts the perception of vertical relations between features in the right human occipito-temporal cortex
Goffaux, Valerie; Rossion, Bruno; Sorger, Bettina et al

in Journal of Neuropsychology (2009), 3

The impact of inversion on the extraction of relational and featural face information was investigated in two fMRI experiments. Unlike previous studies, the contribution of horizontal and vertical spatial ... [more ▼]

The impact of inversion on the extraction of relational and featural face information was investigated in two fMRI experiments. Unlike previous studies, the contribution of horizontal and vertical spatial relations were considered separately since they have been shown to be differentially vulnerable to face inversion (Goffaux & Rossion, 2007). Hence, inversion largely affects the perception of vertical relations (e.g. eye or mouth height) while the processing of features (e.g. eye shape and surface) and of horizontal relations (e.g. inter-ocular distance) is affected to a far lesser extent. Participants viewed pairs of faces that differed either at the level of one local feature (i.e. the eyes) or of the spatial relations of this feature with adjacent features. Changes of spatial relations were divided into two conditions, depending on the vertical or horizontal axis of the modifications. These stimulus conditions were presented in separate blocks in the first (block) experiment while they were presented in a random order in the second event-related (ER) experiment. Face-preferring voxels located in the right-lateralized middle fusiform gyrus (rMFG) largely decreased their activity with inversion. Inversion-related decreases were more moderate in left-lateralized middle fusiform gyrus (lMFG). ER experiment revealed that inversion affected rMFG and lMFG activity in distinct stimulus conditions. Whereas inversion affected lMFG processing only in featural condition, inversion selectively affected the processing of vertical relations in rMFG. Correlation analyses further indicated that the inversion effect (IE) observed in rMFG and right inferior occipital gyrus (rIOG) reliably predicted the large behavioural IE observed for the processing of vertical relations. In contrast, lMFG IE correlated with the weak behavioural IE observed for the processing of horizontal relations. Our findings suggest that face configuration is mostly encoded in rMFG, whereas more local aspects of face information, such as features and horizontal spatial relations drive lMFG processing. These findings corroborate the view that the vulnerability of face perception to inversion stems mainly from the disrupted processing of vertical face relations in the right-lateralized network of face-preferring regions (rMFG, rIOG). [less ▲]

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See detailInvestigation of featural versus configural processing of faces in the middle fusiform gyrus
Goffaux, Valerie; Sorger, Bettina; Schiltz, Christine UL et al

Poster (2007, May)

Inverting a face affects the processing of the vertical relations between features (e.g. eye height) more than the processing of horizontal relations (e.g. interocular distance) and of local features (e.g ... [more ▼]

Inverting a face affects the processing of the vertical relations between features (e.g. eye height) more than the processing of horizontal relations (e.g. interocular distance) and of local features (e.g. eye shape and surface). Inversion also decreases hemodynamic responses (HR) in face-sensitive regions in the middle fusiform gyrus (MFG), presumably because it reduces face distinctiveness and leads to larger adaptation. Here we tested the hypothesis that inversion affects the perception of vertical metric distances between features in the MFG. In the present fMRI study, twelve subjects were presented with short blocks of upright and inverted pairs composed either of identical faces (‘same’ condition), or of faces that differed at the level of ‘vertical’ relations, ‘horizontal’ relations, the shape of all inner feature (‘different’), or the shape of one single ‘feature’. In rMFG, smaller HR were observed for ‘same’ as compared to ‘different’ condition when faces were presented upright; due to HR adaptation. ‘Vertical’, ‘horizontal’ and ‘featural’ conditions led to HR close to ‘same’ condition. Inversion decreased HR in all conditions except the ‘same’ condition, thus replicating previous findings. The largest inversion-related decrements measured in rMFG were observed for vertical relations. In the left MFG, all conditions led to larger HR than the ‘same’ condition at upright. Inversion decreased HR in vertical and horizontal conditions only. These results suggest different roles of the MFG across hemispheres. rMFG may code ecological face differences, since release from adaptation was only observed for completely different faces in this region. Moreover, rMFG may be sensitive to face configuration as suggested by the generalised inversion-related HR decrease. In contrast, lMFG may code any kind of physical difference between faces irrespective of orientation, except for relational differences. [less ▲]

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