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Vannuscorps G, Galaburda A, Caramazza A. From intermediate shape-centered representations to the perception of oriented shapes: response to commentaries. Cogn Neuropsychol 2023; 40:71-94. [PMID: 37642330 DOI: 10.1080/02643294.2023.2250511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/14/2023] [Accepted: 07/31/2023] [Indexed: 08/31/2023]
Abstract
In this response paper, we start by addressing the main points made by the commentators on the target article's main theoretical conclusions: the existence and characteristics of the intermediate shape-centered representations (ISCRs) in the visual system, their emergence from edge detection mechanisms operating on different types of visual properties, and how they are eventually reunited in higher order frames of reference underlying conscious visual perception. We also address the much-commented issue of the possible neural mechanisms of the ISCRs. In the final section, we address more specific and general comments, questions, and suggestions which, albeit very interesting, were less directly focused on the main conclusions of the target paper.
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Affiliation(s)
- Gilles Vannuscorps
- Department of Psychology, Harvard University, Cambridge, MA, USA
- Institute of Psychological Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
- Institute of Neuroscience, Université catholique de Louvain, Louvain-la-Neuve, Belgium
- Louvain Bionics, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Albert Galaburda
- Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Alfonso Caramazza
- Department of Psychology, Harvard University, Cambridge, MA, USA
- Center for Mind/Brain Sciences (CIMeC), Università degli Studi di Trento, Rovereto, Italy
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2
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Vannuscorps G, Galaburda A, Caramazza A. The form of reference frames in vision: The case of intermediate shape-centered representations. Neuropsychologia 2021; 162:108053. [PMID: 34624257 DOI: 10.1016/j.neuropsychologia.2021.108053] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/10/2021] [Accepted: 10/01/2021] [Indexed: 12/01/2022]
Abstract
Although a great deal is known about the early sensory and the later, perceptual, stages of visual processing, far less is known about the nature of intermediate representational units and reference frames. Progress in understanding intermediate levels of representations in vision is hindered by the complexity of interactions among multiple levels of representation in the visual system, making it difficult to isolate and study the nature of each particular level. Nature occasionally provides the opportunity to peer inside complex systems by isolating components of a system through accidental damage or genetic modification of neural components. We have recently reported the case of a young woman who perceives 2D bounded regions of space as if they were plane-rotated by 90, 180 or 270° around their center, mirrored across their own axes, or both. This suggested that an intermediate stage of processing consists in representing mutually exclusive 2D bounded regions extracted from the retinal image in their own "shape-centered" perceptual frame. We proposed to refer to this level of representation as "intermediate shape-centered representation" (ISCR). Here, we used Davida's pattern of errors across 9 experiments as a tool for specifying in greater detail the geometrical properties of the reference frame in which elongated and/or symmetrical shapes are represented at the level of the ISCR. The nature of Davida's errors in these experiments suggests that ISCRs are represented in reference frames composed of orthogonal axes aligned with and centered on the most elongated segment of elongated shapes and, for symmetrical shapes deprived of a straight segment, aligned with their axis of symmetry, and centered on their centroid.
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Affiliation(s)
- G Vannuscorps
- Department of Psychology, Harvard University, Cambridge, MA, 02138, USA; Institute of Psychological Sciences, Université Catholique de Louvain, 1348, Belgium; Institute of Neuroscience, Université Catholique de Louvain, 1348, Belgium; Louvain Bionics, Université Catholique de Louvain, 1348, Belgium.
| | - A Galaburda
- Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, 02215, USA
| | - A Caramazza
- Department of Psychology, Harvard University, Cambridge, MA, 02138, USA; Center for Mind/Brain Sciences (CIMeC), Università Degli Studi di Trento, Rovereto, 38068, Italy
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3
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Abstract
We report the study of a woman who perceives 2D bounded regions of space ("shapes") defined by sharp edges of medium to high contrast as if they were rotated by 90, 180 degrees around their centre, mirrored across their own axes, or both. In contrast, her perception of 3D, strongly blurred or very low contrast shapes, and of stimuli emerging from a collection of shapes, is intact. This suggests that a stage in the process of constructing the conscious visual representation of a scene consists of representing mutually exclusive bounded regions extracted from the initial retinotopic space in "shape-centered" frames of reference. The selectivity of the disorder to shapes originally biased toward the parvocellular subcortical pathway, and the absence of any other type of error, additionally invite new hypotheses about the operations involved in computing these "intermediate shape-centered representations" and in mapping them onto higher frames for perception and action.
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Affiliation(s)
- Gilles Vannuscorps
- Department of Psychology, Harvard University, Cambridge, MA, USA.,Institute of Psychological Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium.,Institute of Neuroscience, Université catholique de Louvain, Louvain-la-Neuve, Belgium.,Louvain Bionics, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Albert Galaburda
- Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Alfonso Caramazza
- Department of Psychology, Harvard University, Cambridge, MA, USA.,Center for Mind/Brain Sciences (CIMeC), Università degli Studi di Trento, Rovereto, Italy
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Levman J, MacDonald P, Rowley S, Stewart N, Lim A, Ewenson B, Galaburda A, Takahashi E. Structural Magnetic Resonance Imaging Demonstrates Abnormal Regionally-Differential Cortical Thickness Variability in Autism: From Newborns to Adults. Front Hum Neurosci 2019; 13:75. [PMID: 30930758 PMCID: PMC6428060 DOI: 10.3389/fnhum.2019.00075] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 02/13/2019] [Indexed: 11/24/2022] Open
Abstract
Autism is a group of complex neurodevelopmental disorders characterized by impaired social interaction and restricted/repetitive behavior. We performed a large-scale retrospective analysis of 1,996 clinical neurological structural magnetic resonance imaging (MRI) examinations of 781 autistic and 988 control subjects (aged 0–32 years), and extracted regionally distributed cortical thickness measurements, including average measurements as well as standard deviations which supports the assessment of intra-regional cortical thickness variability. The youngest autistic participants (<2.5 years) were diagnosed after imaging and were identified retrospectively. The largest effect sizes and the most common findings not previously published in the scientific literature involve abnormal intra-regional variability in cortical thickness affecting many (but not all) regions of the autistic brain, suggesting irregular gray matter development in autism that can be detected with MRI. Atypical developmental patterns have been detected as early as 0 years old in individuals who would later be diagnosed with autism.
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Affiliation(s)
- Jacob Levman
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School Boston, MA, United States.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School Charlestown, MA, United States.,Department of Mathematics, Statistics and Computer Science, St. Francis Xavier University Antigonish, NS, Canada
| | - Patrick MacDonald
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School Boston, MA, United States
| | - Sean Rowley
- Department of Mathematics, Statistics and Computer Science, St. Francis Xavier University Antigonish, NS, Canada
| | - Natalie Stewart
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School Boston, MA, United States
| | - Ashley Lim
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School Boston, MA, United States
| | - Bryan Ewenson
- Department of Mathematics, Statistics and Computer Science, St. Francis Xavier University Antigonish, NS, Canada
| | - Albert Galaburda
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, United States
| | - Emi Takahashi
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School Boston, MA, United States.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School Charlestown, MA, United States
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Levman J, Vasung L, MacDonald P, Rowley S, Stewart N, Lim A, Ewenson B, Galaburda A, Takahashi E. Regional volumetric abnormalities in pediatric autism revealed by structural magnetic resonance imaging. Int J Dev Neurosci 2018; 71:34-45. [PMID: 30110650 DOI: 10.1016/j.ijdevneu.2018.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/26/2018] [Accepted: 08/02/2018] [Indexed: 11/25/2022] Open
Abstract
Autism is a group of complex neurodevelopmental disorders characterized by impaired social interaction, restricted and repetitive behavior. We performed a large-scale retrospective analysis of 1,996 structural magnetic resonance imaging (MRI) examinations of the brain from 1,769 autistic and neurologically typically developing patients (aged 0-32 years), and extracted regional volumetric measurements distributed across 463 brain regions of each patient. The youngest autistic patients (<2.5 years) were diagnosed after imaging and identified retrospectively. Our study demonstrates corpus callosum volumetric abnormalities among autistic patients that are associated with brain overgrowth in early childhood (0-5 years old), followed by a shift towards known decreased volumes in later ages. Results confirm known increases in ventricular volumes among autistic populations and extends those findings to increased volumes of the choroid plexus. Our study also demonstrates distributed volumetric abnormalities among autistic patients that affect a variety of key regional white and grey matter areas of the brain potentially associated with known symptoms of autism.
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Affiliation(s)
- Jacob Levman
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 401 Park Dr., Boston, MA, 02215, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, MA, 02129, USA; Department of Mathematics, Statistics and Computer Science, St. Francis Xavier University, Antigonish, NS, B2G 2W5, Canada.
| | - Lana Vasung
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 401 Park Dr., Boston, MA, 02215, USA
| | - Patrick MacDonald
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 401 Park Dr., Boston, MA, 02215, USA
| | - Sean Rowley
- Department of Mathematics, Statistics and Computer Science, St. Francis Xavier University, Antigonish, NS, B2G 2W5, Canada
| | - Natalie Stewart
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 401 Park Dr., Boston, MA, 02215, USA
| | - Ashley Lim
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 401 Park Dr., Boston, MA, 02215, USA
| | - Bryan Ewenson
- Department of Mathematics, Statistics and Computer Science, St. Francis Xavier University, Antigonish, NS, B2G 2W5, Canada
| | - Albert Galaburda
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave FD-225, Boston, MA, 02215, USA
| | - Emi Takahashi
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 401 Park Dr., Boston, MA, 02215, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, MA, 02129, USA
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Vannuscorps G, Galaburda A, Falk E, Caramazza A. A developmental deficit in seeing the orientation of typical 2D objects. J Vis 2017. [DOI: 10.1167/17.10.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
| | - Albert Galaburda
- Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston (MA), USA
| | | | - Alfonso Caramazza
- Department of Psychology, Harvard University, Cambridge (MA), USACenter for Mind/Brain Sciences, UniversitaÁ degli Studi di Trento, Trento (TN), Italy
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Mills DL, Dai L, Fishman I, Yam A, Appelbaum LG, Galaburda A, Bellugi U, Korenberg JR. Genetic mapping of brain plasticity across development in Williams syndrome: ERP markers of face and language processing. Dev Neuropsychol 2013; 38:613-42. [PMID: 24219698 PMCID: PMC3992981 DOI: 10.1080/87565641.2013.825617] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In Williams Syndrome (WS), a known genetic deletion results in atypical brain function with strengths in face and language processing. We examined how genetic influences on brain activity change with development. In three studies, event-related potentials (ERPs) from large samples of children, adolescents, and adults with the full genetic deletion for WS were compared to typically developing controls, and two adults with partial deletions for WS. Studies 1 and 2 identified ERP markers of brain plasticity in WS across development. Study 3 suggested that, in adults with partial deletions for WS, specific genes may be differentially implicated in face and language processing.
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Affiliation(s)
- D. L. Mills
- School of Psychology, Bangor University, Bangor, UK
| | - L. Dai
- The Brain Institute, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - I. Fishman
- Department of Psychology, San Diego State University, San Diego, CA, USA
| | - A. Yam
- Laboratory for Cognitive Neuroscience, The Salk Institute for Biological Studies, La Jolla, CA, USA
- University of Florida, Gainesville, FL, USA
| | - L. G. Appelbaum
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
| | - A. Galaburda
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, MA, USA
| | - U. Bellugi
- Laboratory for Cognitive Neuroscience, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - J. R. Korenberg
- The Brain Institute, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
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Mimura M, Hoeft F, Kato M, Kobayashi N, Sheau K, Piggot J, Mills D, Galaburda A, Korenberg JR, Bellugi U, Reiss AL. A preliminary study of orbitofrontal activation and hypersociability in Williams Syndrome. J Neurodev Disord 2010; 2:93-98. [PMID: 21304831 PMCID: PMC3034146 DOI: 10.1007/s11689-009-9041-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2009] [Accepted: 11/17/2009] [Indexed: 11/22/2022] Open
Abstract
Individuals with Williams syndrome (WS) demonstrate an abnormally positive social bias. However, the neural substrates of this hypersociability, i.e., positive attribution bias and increased drive toward social interaction, have not fully been elucidated. METHODS: We performed an event-related functional magnetic resonance imaging study while individuals with WS and typically developing controls (TD) matched positive and negative emotional faces. WS compared to TD showed reduced right amygdala activation during presentation of negative faces, as in the previous literature. In addition, WS showed a unique pattern of right orbitofrontal cortex activation. While TD showed medial orbitofrontal cortex activation in response to positive, and lateral orbitofrontal cortex activation to negative, WS showed the opposite pattern. In light of the general notion of a medial/lateral gradient of reward/punishment processing in the orbitofrontal cortex, these findings provide an additional biological explanation for, or correlate of positive attribution bias and hypersociability in WS.
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Affiliation(s)
- Masaru Mimura
- Department of Neuropsychiatry, Showa University School of Medicine, Tokyo, Japan
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Stanford University, School of Medicine, Stanford, CA USA
| | - Fumiko Hoeft
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Stanford University, School of Medicine, Stanford, CA USA
| | - Motoichiro Kato
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Nobuhisa Kobayashi
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Stanford University, School of Medicine, Stanford, CA USA
| | - Kristen Sheau
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Stanford University, School of Medicine, Stanford, CA USA
| | - Judith Piggot
- Department of Child and Adolescent Psychiatry and Psychology, UCLA-NPI, Los Angeles, CA USA
| | - Debra Mills
- School of Psychology, Bangor University, Gwynedd, UK
| | - Albert Galaburda
- Department of Neurology, Beth Israel-Deaconess Medical Center, Harvard Medical School, Boston, MA USA
| | - Julie R. Korenberg
- Center for Integrated Neuroscience and Human Behavior, The Brain Institute, University of Utah, Utah, USA
| | - Ursula Bellugi
- Laboratory for Cognitive Neuroscience, Salk Institute for Biological Studies, La Jolla, CA USA
| | - Allan L. Reiss
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Stanford University, School of Medicine, Stanford, CA USA
- 401 Quarry Rd, Stanford, CA 94305-5795 USA
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Cohen JD, Mock JR, Nichols T, Zadina J, Corey DM, Lemen L, Bellugi U, Galaburda A, Reiss A, Foundas AL. Morphometry of human insular cortex and insular volume reduction in Williams syndrome. J Psychiatr Res 2010; 44:81-9. [PMID: 19660766 PMCID: PMC2813413 DOI: 10.1016/j.jpsychires.2009.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2009] [Revised: 06/29/2009] [Accepted: 07/01/2009] [Indexed: 10/20/2022]
Abstract
Functional imaging in humans and anatomical data in monkeys have implicated the insula as a multimodal sensory integrative brain region. The topography of insular connections is organized by its cytoarchitectonic regions. Previous attempts to measure the insula have utilized either indirect or automated methods. This study was designed to develop a reliable method for obtaining volumetric magnetic resonance imaging (MRI) measurements of the human insular cortex, and to validate that method by examining the anatomy of insular cortex in adults with Williams syndrome (WS) and healthy age-matched controls. Statistical reliability was obtained among three raters for this method, supporting its reproducibility not only across raters, but within different software packages. The procedure described here utilizes native-space morphometry as well as a method for dividing the insula into connectivity-based sub-regions estimated from cytoarchitectonics. Reliability was calculated in both ANALYZE (N=3) and BrainImageJava (N=10) where brain scans were measured once in each hemisphere by each rater. This highly reliable method revealed total, anterior, and posterior insular volume reduction bilaterally (all p's<.002) in WS, after accounting for reduced total brain volumes in these participants. Although speculative, the reduced insular volumes in WS may represent a neural risk for the development of hyperaffiliative social behavior with increased specific phobias, and implicate the insula as a critical limbic integrative region. Native-space quantification of the insula may be valuable in the study of neurodevelopmental or neuropsychiatric disorders related to anxiety and social behavior.
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Affiliation(s)
- Jeremy D Cohen
- Neuroscience Program, Tulane University, New Orleans, LA, United States.
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Gothelf D, Searcy YM, Reilly J, Lai PT, Lanre-Amos T, Mills D, Korenberg JR, Galaburda A, Bellugi U, Reiss AL. Association between cerebral shape and social use of language in Williams syndrome. Am J Med Genet A 2008; 146A:2753-61. [PMID: 18924169 DOI: 10.1002/ajmg.a.32507] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Williams syndrome (WS) is a neurogenetic disorder resulting from a hemizygous microdeletion at band 7q11.23. It is characterized by aberrant development of the brain and a unique profile of cognitive and behavioral features. We sought to identify the neuroanatomical abnormalities that are most strongly associated with WS employing signal detection methodology. Once identified with a Quality Receiver Operating Characteristic Curve (QROC), we hypothesized those brain regions distinguishing subjects with WS from controls would be linked to the social phenotype of individuals with this disorder. Thirty-nine adolescents and young adults with WS and 40 typically developing controls matched for age and gender were studied. The QROC identified a combination of an enlarged ventral anterior prefrontal cortex and large bending angle of the corpus callosum to distinguish between WS and controls with a sensitivity of 85.4% and specificity of 75.0%. Within the WS group, bending angle significantly correlated with ventral anterior prefrontal cortex size but not with other morphometric brain measures. Ventral anterior prefrontal size in subjects with WS was positively associated with the use of social engagement devices in a narrative task assessing the use of social and affective language. Our findings suggest that aberrant morphology of the ventral anterior prefrontal cortex is a pivotal contributing factor to the abnormal size and shape of the cerebral cortex and to the social-affective language use typical of individuals with WS.
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Affiliation(s)
- Doron Gothelf
- Behavioral Neurogenetics Center, Department of Child Psychiatry, Schneider Children's Medical Center of Israel, Petah Tiqwa, Israel.
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Abstract
Parietal lobe impairment is hypothesized to contribute to the dramatic visual-spatial deficits in Williams syndrome (WS). The authors examined the superior and inferior parietal lobule in 17 patients with WS and 17 control female adults (CNLs). The right and left superior parietal lobule gray matter volumes were significantly smaller in patients with WS than in CNLs, even after controlling for total cerebral gray matter. Impaired superior parietal function could explain WS visual-spatial and visual-motor problems.
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Affiliation(s)
- M A Eckert
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA 94305, USA.
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Pennington BF, Filipek PA, Lefly D, Chhabildas N, Kennedy DN, Simon JH, Filley CM, Galaburda A, DeFries JC. A twin MRI study of size variations in human brain. J Cogn Neurosci 2000; 12:223-32. [PMID: 10769318 DOI: 10.1162/089892900561850] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Although it is well known that there is considerable variation among individuals in the size of the human brain, the etiology of less extreme individual differences in brain size is largely unknown. We present here data from the first large twin sample (N=132 individuals) in which the size of brain structures has been measured. As part of an ongoing project examining the brain correlates of reading disability (RD), whole brain morphometric analyses of structural magnetic response image (MRI) scans were performed on a sample of adolescent twins. Specifically, there were 25 monozygotic (MZ) and 23 dizygotic (DZ) pairs in which at least one member of each pair had RD and 9 MZ and 9 DZ pairs in which neither member had RD. We first factor-analyzed volume data for 13 individual brain structures, comprising all of the neocortex and most of the subcortex. This analysis yielded two factors ("cortical" and "subcortical") that accounted for 64% of the variance. We next tested whether genetic and environmental influences on brain size variations varied for these two factors or by hemisphere. We computed intraclass correlations within MZ and DZ pairs in each sample for the cortical and subcortical factor scores, for left and right neocortex, and for the total cerebral volume. All five MZ correlations were substantial (r's=.78 to.98) and significant in both samples, as well as being larger than the corresponding DZ correlations, (r's=0.32 to 0.65) in both samples. The MZ-DZ difference was significant for 3 variables in the RD sample and for one variable in the smaller control sample. These results indicate significant genetic influences on these variables. The magnitude of genetic influence did not vary markedly either for the 2 factors or the 2 hemispheres. There was also a positive correlation between brain size and full-scale IQ, consistent with the results of earlier studies. The total cerebral volume was moderately correlated (r=.42, p<.01, two-tailed) with full-scale IQ in the RD sample; there was a similar trend in the smaller control sample (r=.31, p<.07, two-tailed). Corrections of similar magnitude were found between the subcortical factor and full-scale IQ, whereas the results for the cortical factor (r=.16 and.13) were smaller and not significant. In sum, these results provide evidence for the heritability of individual differences in brain size which do not vary markedly by hemisphere or for neocortex relative to subcortex. Since there are also correlations between brain size and full-scale IQ in this sample, it is possible that genetic influences on brain size partly contribute to individual differences in IQ.
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Affiliation(s)
- B F Pennington
- Department of Psychology, University of Denver, CO 80208, USA
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Pennington BF, Filipek PA, Lefly D, Churchwell J, Kennedy DN, Simon JH, Filley CM, Galaburda A, Alarcon M, DeFries JC. Brain morphometry in reading-disabled twins. Neurology 1999; 53:723-9. [PMID: 10489032 DOI: 10.1212/wnl.53.4.723] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To test for brain structure differences in reading disability (RD) by means of MRI-based morphometry. BACKGROUND Consensus is lacking on the brain structural correlates of RD. The current study reports on a wider set of structures in the largest sample yet studied, controlling for age, gender, IQ, and attention deficit hyperactivity disorder (ADHD). METHODS A case-control study was performed that was comprised of 75 individuals with RD (mean age, 17.43+/-4.29 years) and 22 control subjects without RD (mean age, 18.69+/-3.75 years), each a single member of a twin pair. The two groups were similar in age, gender, and handedness, but differed in full-scale IQ (FSIQ), with the RD group having a lower mean FSIQ (101.8+/-9.9 versus 118.3+/-10.3). Using three group-by-structure analyses of covariance, groups were compared in terms of volume (in cubic centimeters) of major neocortical subdivisions, subcortical structures, and midsagittal areas (in square millimeters) of three subdivisions of the corpus callosum. RESULTS Controlling for age, gender, and IQ, the authors found a significant group-by-structure interaction for the major neocortical subdivisions (p = 0.002), reflecting a different developmental pattern in the RD group, with the insula and anterior superior neocortex being smaller and the retrocallosal cortex being larger in the RD group. In contrast, they found no group main or interaction effects for the subcortical or callosal structures. The pattern of results was essentially the same in subjects without ADHD. CONCLUSIONS Most brain structures do not differ in size in RD, but cortical development is altered subtly. This study replicates in a larger sample previous findings of insular differences in RD and demonstrates further that those differences are not attributable to comorbid ADHD.
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Abstract
Williams syndrome (WMS) is a rare sporadic disorder that yields a distinctive profile of medical, cognitive, neurophysiological, neuroanatomical and genetic characteristics. The cognitive hallmark of WMS is a dissociation between language and face processing (relative strengths) and spatial cognition (profound impairment). Individuals with WMS also tend to be overly social, behavior that is opposite to that seen in autism. A genetic hallmark of WMS is a deletion on chromosome band 7q11.23. Williams syndrome is also associated with specific neuromorphological and neurophysiological profiles: proportional sparing of frontal, limbic and neocerebellar structures is seen using MRI; and abnormal functional organization of the neural systems that underlie both language and face processing is revealed through studies using event-related potentials. The non-uniformity in the cognitive, neuromorphological and neurophysiological domains of WMS make it a compelling model for elucidating the relationships between cognition, the brain and, ultimately, the genes.
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Affiliation(s)
- U Bellugi
- The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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16
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Affiliation(s)
- A Galaburda
- Department of Neurology, Beth Israel Hospital, Boston, Massachusetts 02215
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17
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Abstract
A Golgi survey of the convexity cortex in the brain of the dolphin, Tursiops truncatus, has revealed many cellular characteristics which may be indicative of conservative cortical evolution. These include a high degree of pyramidalization, and an accentuation of layer II. The presence of an accentuated layer II in convexity cortex is a protoneocortical characteristic found in more 'primitive' cortical arrangements. The growth ring concepts of cortical development outward in concentric waves from archicortical and paleocortical origins are discussed. In that context we have not been able to identify cores of hyperspecialization in the dolphin cortex corresponding to koniocortex and gigantopyramidal areas. This leads us to suggest that the cortex of the dolphin reflects a condition of the paralimbic-parinsular stage of evolutionary development. Thus, the dolphin brain may serve as a model of the theoretical mammalian archetype brain and its study may shed light on the organization of the brains of the initial ancestors of modern mammals.
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18
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Abstract
A new cytoarchitectonic study of the human auditory cortex was undertaken in the light of recent knowledge concerning the architecture, fiber connectivity, and physiology of this region in the monkey. The survey of three normative human brains (six hemispheres) processed in whole-brain serial sections disclosed a cytoarchitectonic organization of the cortical auditory region similar to that in the macaque. Unlike the monkey, auditory-related cortex was found in parietal operculum and inferior parietal lobule. Similarities in cortical architectonics between human and monkey brains may provide a rationale for the application of knowledge concerning animal physiology and connectivity to man.
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