• A Continuous Semantic Space Describes the Representation of Thousands of Object and Action Categories across the Human Brain

    Type Journal Article
    Author Alexander G. Huth
    Author Shinji Nishimoto
    Author An T. Vu
    Author Jack L. Gallant
    URL https://linkinghub.elsevier.com/retrieve/pii/S0896627312009348
    Volume 76
    Issue 6
    Pages 1210-1224
    Publication Neuron
    ISSN 08966273
    Date 12/2012
    DOI 10.1016/j.neuron.2012.10.014
    Accessed 3/2/2019, 4:23:03 PM
    Library Catalog Crossref
    Language en
    Abstract Humans can see and name thousands of distinct object and action categories, so it is unlikely that each category is represented in a distinct brain area. A more efficient scheme would be to represent categories as locations in a continuous semantic space mapped smoothly across the cortical surface. To search for such a space, we used fMRI to measure human brain activity evoked by natural movies. We then used voxelwise models to examine the cortical representation of 1,705 object and action categories. The first few dimensions of the underlying semantic space were recovered from the fit models by principal components analysis. Projection of the recovered semantic space onto cortical flat maps shows that semantic selectivity is organized into smooth gradients that cover much of visual and nonvisual cortex. Furthermore, both the recovered semantic space and the cortical organization of the space are shared across different individuals.
    Date Added 3/2/2019, 4:23:03 PM
    Modified 3/2/2019, 4:23:03 PM

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    • Huth et al. - 2012 - A Continuous Semantic Space Describes the Represen.pdf
  • Early Visual Cortex as a Multiscale Cognitive Blackboard

    Type Journal Article
    Author Pieter R. Roelfsema
    Author Floris P. de Lange
    URL http://www.annualreviews.org/doi/10.1146/annurev-vision-111815-114443
    Volume 2
    Issue 1
    Pages 131-151
    Publication Annual Review of Vision Science
    ISSN 2374-4642, 2374-4650
    Date 2016-10-14
    DOI 10.1146/annurev-vision-111815-114443
    Accessed 3/2/2019, 4:32:50 PM
    Library Catalog Crossref
    Language en
    Abstract Neurons in early visual cortical areas not only represent incoming visual information but are also engaged by higher level cognitive processes, including attention, working memory, imagery, and decision-making. Are these cognitive effects an epiphenomenon or are they functionally relevant for these mental operations? We review evidence supporting the hypothesis that the modulation of activity in early visual areas has a causal role in cognition. The modulatory influences allow the early visual cortex to act as a multiscale cognitive blackboard for read and write operations by higher visual areas, which can thereby efficiently exchange information. This blackboard architecture explains how the activity of neurons in the early visual cortex contributes to scene segmentation and working memory, and relates to the subject’s inferences about the visual world. The architecture also has distinct advantages for the processing of visual routines that rely on a number of sequentially executed processing steps.
    Date Added 3/2/2019, 4:32:50 PM
    Modified 3/2/2019, 4:32:50 PM

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    • Roelfsema and de Lange - 2016 - Early Visual Cortex as a Multiscale Cognitive Blac.pdf
  • Functional Compartmentalization and Viewpoint Generalization Within the Macaque Face-Processing System

    Type Journal Article
    Author Winrich A. Freiwald
    Author Doris Y. Tsao
    URL http://science.sciencemag.org/content/330/6005/845
    Rights Copyright © 2010, American Association for the Advancement of Science
    Volume 330
    Issue 6005
    Pages 845-851
    Publication Science
    ISSN 0036-8075, 1095-9203
    Date 2010/11/05
    DOI 10.1126/science.1194908
    Accessed 3/2/2019, 4:28:18 PM
    Library Catalog science.sciencemag.org.revproxy.brown.edu
    Language en
    Abstract Tuned for Faces The temporal lobe of macaques' brains contains six patches of face-selective cortex. This observation has prompted systems neuroscientists to ask, why so many and what do they do? Freiwald and Tsao (p. 845; see the Perspective by Connor) targeted four of these regions for single-unit recordings and found that the different face-selective patches in macaques have independent functions. The areas where earliest processing occurred were most sharply tuned for individual views and least sharply tuned for identity. The mid-level area was more sharply tuned for identity, and the highest processing stage was strongly tuned for identity in a strikingly view-invariant way. These results yield fundamental insights into the computational process of object recognition, the functional organization of the brain, and how representations are transformed through processing hierarchies. Primates can recognize faces across a range of viewing conditions. Representations of individual identity should thus exist that are invariant to accidental image transformations like view direction. We targeted the recently discovered face-processing network of the macaque monkey that consists of six interconnected face-selective regions and recorded from the two middle patches (ML, middle lateral, and MF, middle fundus) and two anterior patches (AL, anterior lateral, and AM, anterior medial). We found that the anatomical position of a face patch was associated with a unique functional identity: Face patches differed qualitatively in how they represented identity across head orientations. Neurons in ML and MF were view-specific; neurons in AL were tuned to identity mirror-symetrically across views, thus achieving partial view invariance; and neurons in AM, the most anterior face patch, achieved almost full view invariance. Recognition of faces from different viewpoints involves several distinct stages of neural processing. Recognition of faces from different viewpoints involves several distinct stages of neural processing.
    Date Added 3/2/2019, 4:28:18 PM
    Modified 3/2/2019, 4:28:18 PM

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  • Long-range and local circuits for top-down modulation of visual cortex processing

    Type Journal Article
    Author Siyu Zhang
    Author Min Xu
    Author Tsukasa Kamigaki
    Author Johnny Phong Hoang Do
    Author Wei-Cheng Chang
    Author Sean Jenvay
    Author Kazunari Miyamichi
    Author Liqun Luo
    Author Yang Dan
    URL http://science.sciencemag.org/content/345/6197/660
    Rights Copyright © 2014, American Association for the Advancement of Science
    Volume 345
    Issue 6197
    Pages 660-665
    Publication Science
    ISSN 0036-8075, 1095-9203
    Date 2014/08/08
    Extra PMID: 25104383
    DOI 10.1126/science.1254126
    Accessed 3/2/2019, 4:33:39 PM
    Library Catalog science.sciencemag.org.revproxy.brown.edu
    Language en
    Abstract You only see what you want to see We often focus on a particular item out of a thousand objects in a visual scene. This ability is called selective attention. Selective attention enhances the responses of sensory nerve cells to whatever is being observed and dampens responses to any distractions. Zhang et al. identified a region of the mouse forebrain that modulates responses in the visual cortex. This modulation improved the mouse's performance in a visual task. Science, this issue p. 660 Top-down modulation of sensory processing allows the animal to select inputs most relevant to current tasks. We found that the cingulate (Cg) region of the mouse frontal cortex powerfully influences sensory processing in the primary visual cortex (V1) through long-range projections that activate local γ-aminobutyric acid–ergic (GABAergic) circuits. Optogenetic activation of Cg neurons enhanced V1 neuron responses and improved visual discrimination. Focal activation of Cg axons in V1 caused a response increase at the activation site but a decrease at nearby locations (center-surround modulation). Whereas somatostatin-positive GABAergic interneurons contributed preferentially to surround suppression, vasoactive intestinal peptide-positive interneurons were crucial for center facilitation. Long-range corticocortical projections thus act through local microcircuits to exert spatially specific top-down modulation of sensory processing. Projections from the frontal cortex control stimulus processing in the visual system in mice. Projections from the frontal cortex control stimulus processing in the visual system in mice.
    Date Added 3/2/2019, 4:33:39 PM
    Modified 3/2/2019, 4:33:39 PM

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  • Object Representation in Inferior Temporal Cortex Is Organized Hierarchically in a Mosaic-Like Structure

    Type Journal Article
    Author Takayuki Sato
    Author Go Uchida
    Author Mark D. Lescroart
    Author Jun Kitazono
    Author Masato Okada
    Author Manabu Tanifuji
    URL http://www.jneurosci.org/content/33/42/16642
    Rights Copyright © 2013 the authors 0270-6474/13/3316642-15$15.00/0
    Volume 33
    Issue 42
    Pages 16642-16656
    Publication Journal of Neuroscience
    ISSN 0270-6474, 1529-2401
    Date 2013/10/16
    Extra PMID: 24133267
    Journal Abbr J. Neurosci.
    DOI 10.1523/JNEUROSCI.5557-12.2013
    Accessed 3/2/2019, 4:29:02 PM
    Library Catalog www.jneurosci.org.revproxy.brown.edu
    Language en
    Abstract There are two dominant models for the functional organization of brain regions underlying object recognition. One model postulates category-specific modules while the other proposes a distributed representation of objects with generic visual features. Functional imaging techniques relying on metabolic signals, such as fMRI and optical intrinsic signal imaging (OISI), have been used to support both models, but due to the indirect nature of the measurements in these techniques, the existing data for one model cannot be used to support the other model. Here, we used large-scale multielectrode recordings over a large surface of anterior inferior temporal (IT) cortex, and densely mapped stimulus-evoked neuronal responses. We found that IT cortex is subdivided into distinct domains characterized by similar patterns of responses to the objects in our stimulus set. Each domain spanned several millimeters on the cortex. Some of these domains represented faces (“face” domains) or monkey bodies (“monkey-body” domains). We also identified domains with low responsiveness to faces (“anti-face” domains). Meanwhile, the recording sites within domains that displayed category selectivity showed heterogeneous tuning profiles to different exemplars within each category. This local heterogeneity was consistent with the stimulus-evoked feature columns revealed by OISI. Taken together, our study revealed that regions with common functional properties (domains) consist of a finer functional structure (columns) in anterior IT cortex. The “domains” and previously proposed “patches” are rather like “mosaics” where a whole mosaic is characterized by overall similarity in stimulus responses and pieces of the mosaic correspond to feature columns.
    Date Added 3/2/2019, 4:29:02 PM
    Modified 3/2/2019, 4:29:02 PM

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  • Performance-optimized hierarchical models predict neural responses in higher visual cortex

    Type Journal Article
    Author D. L. K. Yamins
    Author H. Hong
    Author C. F. Cadieu
    Author E. A. Solomon
    Author D. Seibert
    Author J. J. DiCarlo
    URL http://www.pnas.org/cgi/doi/10.1073/pnas.1403112111
    Volume 111
    Issue 23
    Pages 8619-8624
    Publication Proceedings of the National Academy of Sciences
    ISSN 0027-8424, 1091-6490
    Date 2014-06-10
    DOI 10.1073/pnas.1403112111
    Accessed 3/2/2019, 4:25:33 PM
    Library Catalog Crossref
    Language en
    Date Added 3/2/2019, 4:25:33 PM
    Modified 3/2/2019, 4:25:33 PM

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    • Yamins et al. - 2014 - Performance-optimized hierarchical models predict .pdf
  • Representational similarity analysis – connecting the branches of systems neuroscience

    Type Journal Article
    Author Nikolaus Kriegeskorte
    URL http://journal.frontiersin.org/article/10.3389/neuro.06.004.2008/abstract
    Publication Frontiers in Systems Neuroscience
    ISSN 16625137
    Date 2008
    DOI 10.3389/neuro.06.004.2008
    Accessed 3/2/2019, 4:24:25 PM
    Library Catalog Crossref
    Language en
    Abstract A fundamental challenge for systems neuroscience is to quantitatively relate its three major branches of research: brain-activity measurement, behavioral measurement, and computational modeling. Using measured brain-activity patterns to evaluate computational network models is complicated by the need to define the correspondency between the units of the model and the channels of the brain-activity data, e.g., single-cell recordings or voxels from functional magnetic resonance imaging (fMRI). Similar correspondency problems complicate relating activity patterns between different modalities of brain-activity measurement (e.g., fMRI and invasive or scalp electrophysiology), and between subjects and species. In order to bridge these divides, we suggest abstracting from the activity patterns themselves and computing representational dissimilarity matrices (RDMs), which characterize the information carried by a given representation in a brain or model. Building on a rich psychological and mathematical literature on similarity analysis, we propose a new experimental and data-analytical framework called representational similarity analysis (RSA), in which multi-channel measures of neural activity are quantitatively related to each other and to computational theory and behavior by comparing RDMs. We demonstrate RSA by relating representations of visual objects as measured with fMRI in early visual cortex and the fusiform face area to computational models spanning a wide range of complexities.The RDMs are simultaneously related via second-level application of multidimensional scaling and tested using randomization and bootstrap techniques. We discuss the broad potential of RSA, including novel approaches to experimental design, and argue that these ideas, which have deep roots in psychology and neuroscience, will allow the integrated quantitative analysis of data from all three branches, thus contributing to a more unified systems neuroscience.
    Date Added 3/2/2019, 4:24:25 PM
    Modified 3/2/2019, 4:24:25 PM

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    • Kriegeskorte - 2008 - Representational similarity analysis – connecting .pdf
  • Searching for visual features that explain response variance of face neurons in inferior temporal cortex

    Type Journal Article
    Author Takashi Owaki
    Author Michel Vidal-Naquet
    Author Yunjun Nam
    Author Go Uchida
    Author Takayuki Sato
    Author Hideyuki Câteau
    Author Shimon Ullman
    Author Manabu Tanifuji
    URL https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0201192
    Volume 13
    Issue 9
    Pages e0201192
    Publication PLOS ONE
    ISSN 1932-6203
    Date Sep 20, 2018
    Journal Abbr PLOS ONE
    DOI 10.1371/journal.pone.0201192
    Accessed 3/2/2019, 4:27:02 PM
    Library Catalog PLoS Journals
    Language en
    Abstract Despite a large body of research on response properties of neurons in the inferior temporal (IT) cortex, studies to date have not yet produced quantitative feature descriptions that can predict responses to arbitrary objects. This deficit in the research prevents a thorough understanding of object representation in the IT cortex. Here we propose a fragment-based approach for finding quantitative feature descriptions of face neurons in the IT cortex. The development of the proposed method was driven by the assumption that it is possible to recover features from a set of natural image fragments if the set is sufficiently large. To find the feature from the set, we compared object responses predicted from each fragment and responses of neurons to these objects, and search for the fragment that revealed the highest correlation with neural object responses. Prediction of object responses of each fragment was made by normalizing Euclidian distance between the fragment and each object to 0 to 1 such that the smaller distance gives the higher value. The distance was calculated at the space where images were transformed to a local orientation space by a Gabor filter and a local max operation. The method allowed us to find features with a correlation coefficient between predicted and neural responses of 0.68 on average (number of object stimuli, 104) from among 560,000 feature candidates, reliably explaining differential responses among faces as well as a general preference for faces over to non-face objects. Furthermore, predicted responses of the resulting features to novel object images were significantly correlated with neural responses to these images. Identification of features comprising specific, moderately complex combinations of local orientations and colors enabled us to predict responses to upright and inverted faces, which provided a possible mechanism of face inversion effects. (292/300).
    Date Added 3/2/2019, 4:27:02 PM
    Modified 3/2/2019, 4:27:02 PM

    Tags:

    • Face
    • Face recognition
    • Facies (medical)
    • Head
    • Monkeys
    • Neuronal tuning
    • Neurons
    • Vision

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