fMRI of the Face-Processing Network in the Ventral Temporal Lobe of Awake and Anesthetized Macaques

Ku, Shih-Pi; Tolias, Andreas S.; Logothetis, Nikos K.; Goense, Jozien

doi:10.1016/j.neuron.2011.02.048

Cited by 123 publications

(94 citation statements)

References 63 publications

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“…Thus, it is possible that this dorsal-ventral asymmetry is simply reflected in our fMRI results. Alternatively, the apparent absence of a distinguishable curvature-biased patch in ventral V4 might be due to signal drop-off in this cortical region, which has been reported in previous studies (48,49).…”

Section: Discussionmentioning

confidence: 57%

Curvature-processing network in macaque visual cortex

Yue

Pourladian

Tootell

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Our visual environment abounds with curved features. Thus, the goal of understanding visual processing should include the processing of curved features. Using functional magnetic resonance imaging in behaving monkeys, we demonstrated a network of cortical areas selective for the processing of curved features. This network includes three distinct hierarchically organized regions within the ventral visual pathway: a posterior curvature-biased patch (PCP) located in the near-foveal representation of dorsal V4, a middle curvature-biased patch (MCP) located on the ventral lip of the posterior superior temporal sulcus (STS) in area TEO, and an anterior curvature-biased patch (ACP) located just below the STS in anterior area TE. Our results further indicate that the processing of curvature becomes increasingly complex from PCP to ACP. The proximity of the curvature-processing network to the well-known face-processing network suggests a possible functional link between them.curvature patches | face patches | curved Gabor filters D ecades of research have focused on understanding visual feature processing, particularly along the ventral visual pathway. Such studies have shown that neurons in lower-order visual areas (e.g., V1) respond strongly to simple oriented contours (1), whereas neurons in higher-order visual areas (e.g., inferior temporal cortex) respond selectively to more complex image features and/or visual categories (2-4), in ways that are not yet fully understood. To link these extremes in visual information processing, many studies have aimed to clarify the optimal "trigger" features at intermediate levels of the visual cortical hierarchy.Among these features, stimulus curvature has not been well studied. This is surprising because, strictly, all lines are curved to some extent, except for the single exception of a perfectly straight line. This ubiquity of curved shapes also extends to 3D surfaces (5). In nature, where much of our visual system presumably evolved, perfectly flat surfaces are rare. Even the flattest of natural features (e.g., oceans, sandy beaches) are often curved to some extent, due to wind, water motion, and even the curvature of the earth. Thus, it is important to understand curvature processing to fully unravel the steps in cortical visual processing.Among the few studies to test single neuron responses to curvature per se, Gallant et al. (6,7) reported that a significant percentage of neurons in macaque cortical area V4 is selective for curved stimuli. Intriguingly, these authors also noted that neurons preferring curved patterns were often anatomically clustered together. Subsequently, demonstrated that neurons in the parafoveal representation of dorsal V4 respond robustly to the curvature component of complex shapes. To our knowledge, there have been no systematic studies of curvature at levels below V4 in macaques.Intriguingly, some evidence suggests that the processing of curvature may interact selectively with the processing of faces. For instance, perceptual deficits in face reco...

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Section: Discussionmentioning

confidence: 57%

Curvature-processing network in macaque visual cortex

Yue

Pourladian

Tootell

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…A large number of studies in various mammalian species reveal differences in the result patterns of (rs)fMRI studies under awake and anaesthetized conditions [4,7,11,12]. Since different bird species represent interesting models for the analyses of neural plasticity, song production, learning, and cognition, it is necessary to develop and test a procedure for awake bird MRI.…”

Section: Mri Of Awake Pigeonsmentioning

confidence: 99%

“…rats [7][8][9] and mice [10]. Moreover since it is shown that both in human [11] and nonhuman primates [12] brain state during rest is not fully comparable with the anesthetized state, new studies increasingly start to study rsfMRI in awake rodents [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Functional MRI and functional connectivity of the visual system of awake pigeons

Groof

Jonckers

Güntürkün

et al. 2013

Behavioural Brain Research

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h i g h l i g h t sFirst study to image the whole brain of awake pigeons. We show a habituation program for MR-sessions under awake and head-fixed conditions. Movement under these conditions is minimal. First measurement of functional connectivity in a non-mammalian species. Analyses of BOLD-response and functional connectivity are feasible. a r t i c l e i n f o b s t r a c tAt present, functional MRI (fMRI) is increasingly used in animal research but the disadvantage is that the majority of the imaging is applied in anaesthetized animals. Only a few articles present results obtained in awake rodents. In this study both traditional fMRI and resting state (rsfMRI) were applied to four pigeons, that were trained to remain still while being imaged, removing the need for anesthesia. This is the first time functional connectivity measurements are performed in a non-mammalian species. Since the visual system of pigeons is a well-known model for brain asymmetry, the focus of the study was on the neural substrate of the visual system. For fMRI a visual stimulus was used and functional connectivity measurements were done with the entopallium (E; analog for the primary visual cortex) as a seed region. Interestingly in awake pigeons the left E was significantly functionally connected to the right E. Moreover we compared connectivity maps for a seed region in both hemispheres resulting in a stronger bilateral connectivity starting from left E then from right E. These results could be used as a starting point for further imaging studies in awake birds and also provide a new window into the analysis of hemispheric dominance in the pigeon.

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“…The equivalent of the human FFA, seems to be still elusive (Ku et al, 2011), but a network of areas that respond more to faces than to other objects has been repeatedly shown with fMRI in the macaque brain including the temporal and prefrontal cortex, and the amygdala (Logothetis et al, 1999), (Tsao et al, 2003), (Hoffman et al, 2007), (Tsao et al, 2008b), (Tsao et al, 2008a), (Ku et al, 2011). The exact role of each face patch is not clear, but what we do know is that it only takes a small amount of micro-stimulation of a small group of face selective neurons to affect the perception of a macaque categorizing face vs. non-face stimuli and bias the response towards the face category (Afraz et al, 2006).…”

Section: Other Selective Modules: Bodies Places Wordsmentioning

confidence: 99%

“…15). However, it should be noted that the majority of these face patches are also active in the anaesthetised preparation (Logothetis et al, 1999), (Ku et al, 2011), complicating the interpretation of the findings and the role of these activations in conscious perception. …”

Section: Other Selective Modules: Bodies Places Wordsmentioning

confidence: 99%

The Contribution of fMRI in the Study of Visual Categorization and Expertise

Sigala¹

2014

Advanced Brain Neuroimaging Topics in Health and Disease - Methods and Applications

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fMRI of the Face-Processing Network in the Ventral Temporal Lobe of Awake and Anesthetized Macaques

Cited by 123 publications

References 63 publications

Curvature-processing network in macaque visual cortex

Curvature-processing network in macaque visual cortex

Functional MRI and functional connectivity of the visual system of awake pigeons

The Contribution of fMRI in the Study of Visual Categorization and Expertise

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