دانلود مقاله ISI انگلیسی شماره 37686
عنوان فارسی مقاله

حالت چهره و جهت نگاه در شیار گیجگاهی برتر انسانی

کد مقاله سال انتشار مقاله انگلیسی ترجمه فارسی تعداد کلمات
37686 2007 8 صفحه PDF سفارش دهید محاسبه نشده
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عنوان انگلیسی
Facial expression and gaze-direction in human superior temporal sulcus
منبع

Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)

Journal : Neuropsychologia, Volume 45, Issue 14, 2007, Pages 3234–3241

کلمات کلیدی
نگاه - بیان - صورت - ادراک - ارتباط غیر کلامی
پیش نمایش مقاله
پیش نمایش مقاله حالت چهره و جهت نگاه در شیار گیجگاهی برتر انسانی

چکیده انگلیسی

Abstract The perception of facial expression and gaze-direction are important aspects of non-verbal communication. Expressions communicate the internal emotional state of others while gaze-direction offers clues to their attentional focus and future intentions. Cortical regions in the superior temporal sulcus (STS) play a central role in the perception of expression and gaze, but the extent to which the neural representations of these facial gestures are overlapping is unknown. In the current study 12 subjects observed neutral faces with direct-gaze, neutral faces with averted-gaze, or emotionally expressive faces with direct-gaze while we scanned their brains with functional magnetic resonance imaging (fMRI), allowing a comparison of the hemodynamic responses evoked by perception of expression and averted-gaze. The inferior occipital gyri, fusiform gyri, STS and inferior frontal gyrus were more strongly activated when subjects saw facial expressions than when they saw neutral faces. The right STS was more strongly activated by the perception of averted-gaze than direct-gaze faces. A comparison of the responses within right STS revealed that expression and averted-gaze activated distinct, though overlapping, regions of cortex. We propose that gaze-direction and expression are represented by dissociable overlapping neural systems.

نتیجه گیری انگلیسی

. Results 2.1. General linear model results All reported activations are significant at a p level of p ≤ 0.05 (corrected) unless otherwise noted. 2.2. Effect of facial expression A linear contrast of the regression coefficients was performed in order to identify voxels that demonstrated a greater response to faces displaying an emotional expression than to those displaying a neutral expression with direct-gaze. This contrast revealed voxel clusters in the bilateral STS, the right inferior frontal gyrus, and the bilateral occipital lobe that showed a stronger response to facial expressions (see Table 1 and Fig. 2). There were no clusters that showed a stronger response to neutral faces with direct-gaze. Table 1. Brain regions with stronger responses to faces displaying an emotional expression than to those displaying a neutral expression (p < 0.05, corrected, N = 12) Region Maximum t-value Volume (mm3) x y z Right middle occipital gyrusa 12.30 7507 32 −77 0 Left lingual gyrusa 8.08 7434 −17 −85 3 Right inferior frontal gyrus 9.50 6373 45 16 22 Right superior temporal sulcus 8.80 5907 52 −48 8 Left superior temporal sulcus 7.99 4539 −55 −60 10 a Cluster includes the inferior occipital gyrus and extends into the lateral fusiform gyrus. Table options Brain activity overlaid on a standardized brain. Yellow indicates voxels that ... Fig. 2. Brain activity overlaid on a standardized brain. Yellow indicates voxels that showed a greater response to facial expressions than to control stimuli (neutral faces with direct-gaze). Blue indicates voxels that showed a greater response to faces with averted-gaze than to control stimuli. Green indicates voxels that showed a greater response to facial expressions than to control and a greater response to averted-gaze than to control. Figure options 2.3. Effect of averted-gaze A linear contrast of the regression coefficients was performed in order to identify voxels that demonstrated a greater response to neutral faces with averted-gaze than to those with direct-gaze. This contrast revealed a cluster of voxels in the right STS region (see Table 2 and Fig. 2) that showed a stronger response to averted-gaze. There were no clusters that showed a stronger response to direct-gaze than to averted-gaze. Table 2. Brain region with stronger responses to faces displaying an averted-gaze than to those displaying a direct-gaze (p < 0.05, corrected, N = 12) Region Maximum t-value Volume (mm3) x y z Right superior temporal sulcus 9.37 1878 36 −54 15 Table options 2.4. Expression > averted-gaze A linear contrast of the regression coefficients was performed in order to identify voxels that demonstrated a greater response to faces displaying an emotional expression (direct-gaze) than to faces displaying an averted-gaze (neutral expression). This contrast revealed two large bilateral occipito-temporal clusters that showed a greater response to facial expressions. These clusters include the inferior occipital gyrus and extended bilaterally into the lateral fusiform gyrus (Table 3). There were no clusters that showed a stronger response to averted-gaze than to facial expression. Table 3. Brain region with stronger responses to faces displaying an emotional expression and direct-gaze than to those displaying a neutral expression and averted-gaze (p < 0.05, corrected, N = 12) Region Maximum t-value Volume (mm3) x y z Right cuneus/middle occipital/fusiform gyri 13.67 22,020 43 −58 −4 Left cuneus/middle occipital/fusiform gyri 10.43 18,717 −21 −91 3 Table options 2.5. Response selectivity maps A response selectivity map was created in order to compare the conjunction of regions that demonstrated significant activation for expression > control and/or averted-gaze > control. The map shows voxels that have one of three response profiles; greater response to expression than control; greater response to averted-gaze than to control; greater response to expression than to control and to averted-gaze than to control. These voxels clustered into three distinct overlapping regions in the right STS (see Fig. 2). Those voxels most sensitive to expression formed a region inferior and anterior to those most sensitive to averted-gaze, with those most sensitive to both occupying the space between. The functional dissociation of these regions was noted across individual subjects as well as at the group level. Indeed, one subject did not have a single voxel with a significant effect for both the expression > control and averted-gaze > control contrasts. The spatial pattern of expression sensitive and averted-gaze sensitive voxels along the S–I axis in the group analysis also was largely evident in individual subjects, as the averted-gaze region was superior to the expression region in 10 of 12 ( Supplementary Fig. S3). 2.6. Time-course analysis The time-course analysis (Fig. 3) illustrates the response profile of the regions identified by the selectivity maps (Fig. 2). Notably, the expression-selective voxels in the STS responded significantly to all face conditions as compared to baseline. These time courses also reveal a clear increase in the hemodyanmic response evoked by the test face across all conditions and regions of interest. The mean time series averaged across voxels within regions of interest: (a) mean ... Fig. 3. The mean time series averaged across voxels within regions of interest: (a) mean response of voxels within posterior right STS that show a greater response to facial expressions that to control stimuli (neutral faces with direct-gaze), (b) mean response of voxels within posterior right STS that show a greater response to faces with averted-gaze than to control stimuli, (c) mean response of voxels within posterior right STS that show a greater response to facial expressions than to control and a greater response to averted-gaze than to control. The time series begins 8 s prior to the beginning of the stimulation stimulus block and terminates 8 s after presentation of the test face. Figure options Within the face-responsive region of right ventral temporal cortex, perception of emotionally expressive faces elicited a significantly stronger response than averted-gaze faces (p < 0.01). The signal evoked by expressive faces also was greater than the signal evoked by control faces (p = 0.02). Conversely, the signal evoked by averted-gaze faces was less than the signal evoked by control faces (p = 0.06). These differences were most prominent in separate regions of the time course. Expression was most significantly different from control in the late half of the block (TRs 6–9; p = 0.00003) whereas averted-gaze was significantly less than control in the early part of the block (TRs 4–5; p = 0.02).

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