Limits...
Image-invariant responses in face-selective regions do not explain the perceptual advantage for familiar face recognition.

Davies-Thompson J, Newling K, Andrews TJ - Cereb. Cortex (2012)

Bottom Line: Here, we used an functional magnetic resonance-adaptation paradigm to investigate image invariance in face-selective regions of the human brain.We found clear evidence for a degree of image-invariant adaptation to facial identity in face-selective regions, such as the fusiform face area.This suggests that the marked differences in the perception of familiar and unfamiliar faces may not depend on differences in the way multiple images are represented in core face-selective regions of the human brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, York Neuroimaging Centre, University of York, York YO10 5DD, UK.

ABSTRACT
The ability to recognize familiar faces across different viewing conditions contrasts with the inherent difficulty in the perception of unfamiliar faces across similar image manipulations. It is widely believed that this difference in perception and recognition is based on the neural representation for familiar faces being less sensitive to changes in the image than it is for unfamiliar faces. Here, we used an functional magnetic resonance-adaptation paradigm to investigate image invariance in face-selective regions of the human brain. We found clear evidence for a degree of image-invariant adaptation to facial identity in face-selective regions, such as the fusiform face area. However, contrary to the predictions of models of face processing, comparable levels of image invariance were evident for both familiar and unfamiliar faces. This suggests that the marked differences in the perception of familiar and unfamiliar faces may not depend on differences in the way multiple images are represented in core face-selective regions of the human brain.

Show MeSH

Related in: MedlinePlus

Location of face-selective regions (FFA, OFA, STS).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3539454&req=5

fig3: Location of face-selective regions (FFA, OFA, STS).

Mentions: To identify regions responding selectively to faces in the visual cortex, a localizer scan was carried out for each participant. There were 5 conditions: faces, bodies, objects, places, or Fourier-scrambled images from each category. All images were presented in gray scale. Participants viewed images from each category in stimulus blocks that contained 10 images. Each image was presented for 700 ms followed by a 200 ms fixation cross. Stimulus blocks were separated by a 9 s fixation gray screen. Each condition was repeated 4 times, in a counterbalanced block design, giving 20 stimulus blocks. For the localizer scan, face-selective regions of interest (ROIs) were determined by the averaged contrasts of “face > places, faces > objects, faces > places, and faces > scrambled,” thresholded at P < 0.001 (uncorrected). This analysis revealed 3 face-selective regions: FFA, occipital face area (OFA), and posterior temporal sulcus (pSTS) that were identified for each individual (Fig. 3). Data from the left and right hemisphere were combined for each participant for each ROI. The time series of each voxel within a region was converted from units of image intensity to percentage signal change. All voxels in a given ROI were then averaged to give a single time series in each ROI for each participant. The peak response was calculated as an average of the response at 9 and 12 s after the onset of a block. Repeated-measures analyses of variance (ANOVA) were used to determine differences in response to each stimulus condition.


Image-invariant responses in face-selective regions do not explain the perceptual advantage for familiar face recognition.

Davies-Thompson J, Newling K, Andrews TJ - Cereb. Cortex (2012)

Location of face-selective regions (FFA, OFA, STS).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539454&req=5

fig3: Location of face-selective regions (FFA, OFA, STS).
Mentions: To identify regions responding selectively to faces in the visual cortex, a localizer scan was carried out for each participant. There were 5 conditions: faces, bodies, objects, places, or Fourier-scrambled images from each category. All images were presented in gray scale. Participants viewed images from each category in stimulus blocks that contained 10 images. Each image was presented for 700 ms followed by a 200 ms fixation cross. Stimulus blocks were separated by a 9 s fixation gray screen. Each condition was repeated 4 times, in a counterbalanced block design, giving 20 stimulus blocks. For the localizer scan, face-selective regions of interest (ROIs) were determined by the averaged contrasts of “face > places, faces > objects, faces > places, and faces > scrambled,” thresholded at P < 0.001 (uncorrected). This analysis revealed 3 face-selective regions: FFA, occipital face area (OFA), and posterior temporal sulcus (pSTS) that were identified for each individual (Fig. 3). Data from the left and right hemisphere were combined for each participant for each ROI. The time series of each voxel within a region was converted from units of image intensity to percentage signal change. All voxels in a given ROI were then averaged to give a single time series in each ROI for each participant. The peak response was calculated as an average of the response at 9 and 12 s after the onset of a block. Repeated-measures analyses of variance (ANOVA) were used to determine differences in response to each stimulus condition.

Bottom Line: Here, we used an functional magnetic resonance-adaptation paradigm to investigate image invariance in face-selective regions of the human brain.We found clear evidence for a degree of image-invariant adaptation to facial identity in face-selective regions, such as the fusiform face area.This suggests that the marked differences in the perception of familiar and unfamiliar faces may not depend on differences in the way multiple images are represented in core face-selective regions of the human brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, York Neuroimaging Centre, University of York, York YO10 5DD, UK.

ABSTRACT
The ability to recognize familiar faces across different viewing conditions contrasts with the inherent difficulty in the perception of unfamiliar faces across similar image manipulations. It is widely believed that this difference in perception and recognition is based on the neural representation for familiar faces being less sensitive to changes in the image than it is for unfamiliar faces. Here, we used an functional magnetic resonance-adaptation paradigm to investigate image invariance in face-selective regions of the human brain. We found clear evidence for a degree of image-invariant adaptation to facial identity in face-selective regions, such as the fusiform face area. However, contrary to the predictions of models of face processing, comparable levels of image invariance were evident for both familiar and unfamiliar faces. This suggests that the marked differences in the perception of familiar and unfamiliar faces may not depend on differences in the way multiple images are represented in core face-selective regions of the human brain.

Show MeSH
Related in: MedlinePlus