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Eran Zaidel - One of the best experts on this subject based on the ideXlab platform.

  • alexithymia interHemispheric transfer and right Hemispheric Specialization a critical review
    Psychotherapy and Psychosomatics, 2005
    Co-Authors: Golnaz Tabibnia, Eran Zaidel
    Abstract:

    Background: One neural model of alexithymia relates the condition to poor interHemispheric transfer, while another model associates it with a disturbance in right hemisphere activity. Methods: The available empirical evidence directly relating alexithymia to a deficit in interHemispheric transfer and/or in right hemisphere activity is critically reviewed. Results: The interHemispheric transfer studies have related alexithymia to a deficit in transfer, but the nature and directionality of the transfer deficit have yet to be determined. Many of the Hemispheric Specialization studies do not relate alexithymia to a right hemisphere dysfunction. Shortcomings of these studies are reviewed. Conclusions: The hypothesis that alexithymia is related to a deficit in the right-to-left transfer of emotional information and to a right hemisphere impairment in emotion processing remains to be tested directly and definitively. Suggestions for future research are made.

  • lateralized lexical decision in schizophrenia Hemispheric Specialization and interHemispheric lexicality priming
    Journal of Abnormal Psychology, 2003
    Co-Authors: Katherine L Narr, Michael F Green, Linda Capetillocunliffe, Arthur W Toga, Eran Zaidel
    Abstract:

    Reports of left-hemisphere dysfunction and abnormal interHemispheric transfer in schizophrenia are mixed. The authors used a unified paradigm, the lateralized lexical decision task, to assess Hemispheric Specialization in word recognition, Hemispheric error monitoring, and interHemispheric transfer in male, right-handed participants with schizophrenia (n=34) compared with controls (n=20). Overall, performance and error monitoring were worse in patients. However, patients like controls showed left-hemisphere superiority for lexical processing and right-hemisphere superiority for error monitoring. Only patients showed selective-interHemispheric lexicality priming for accuracy, in which performance improved when the lexical status of target and distractor stimuli presented to each hemifield was congruent. Results suggest that schizophrenia is associated with impaired monitoring and with increased interHemispheric automatic information transfer rather than with changed Hemispheric Specialization for language or error monitoring.

  • complementary Hemispheric Specialization for word and accent detection
    NeuroImage, 2003
    Co-Authors: M Mandelkern, Steven M Berman, Hao Phan, Eran Zaidel
    Abstract:

    When we hear a familiar word pronounced in a foreign accent, which parts of the brain identify the word and which identify the accent? Here we present converging evidence from PET blood flow, event-related scalp potentials, and behavioral responses during dichotic listening, showing homologous and complementary Hemispheric Specialization for word and accent detection. Accuracy of detecting target words was greater when stimuli were presented to the right ear, indicating left hemisphere Specialization, with no ear advantage for detecting target accents. Detection of words also produced increased blood flow in a left frontal area associated with motor and phonetic processing, and a left temporal area associated with semantic memory. Homologous areas of the right hemisphere, together with right prefrontal and precuneus regions, showed increased blood flow during detection of accents. Separate analyses for each detection task indicated that voxels whose activity maximally correlated with accuracy were in the left hemisphere for word detection, but in the right hemisphere for accent detection. Voxels whose activity maximally correlated with inaccuracy were in the opposite hemisphere for both tasks, strengthening the interpretation that between-task differences in brain activation are related to lateralized Specializations for task performance. ERP waveforms and reaction times suggested that greater left hemisphere activation during word detection preceded greater right hemisphere activation during accent detection. The results are interpreted as supporting left hemisphere Specialization for extraction of the linguistic, phonetic, and semantic information contained in speech, and right hemisphere Specialization for pragmatics, the social context of linguistic communication.

  • Individual Differences in the Hemispheric Specialization of Dual Route Variables
    Brain and Language, 1999
    Co-Authors: N.y. Weekes, L. Capetillo-cunliffe, Janice Rayman, Marco Iacoboni, Eran Zaidel
    Abstract:

    The dual route model suggests that reading of letter strings can occur through both a lexical and a nonlexical route. Hemispheric Specialization of these routes has also been posited, suggesting that the left hemisphere has both lexical and nonlexical routes while the right hemisphere has only a lexical route. However, some recent data conflict with this Hemispheric dual route model, suggesting that both hemispheres may have access to both routes. The purpose of the present study was to investigate individual differences in the Hemispheric Specialization of these routes and to determine whether these group differences in their Specialization might explain conflicts in the literature. The effect of four individual difference factors was explored: handedness, biological sex, menstrual stage (i.e., fluctuations in estrogen), and self-rated degree of masculinity (i.e., sexual attribution). We looked at the interaction of these individual differences with the following dual route variables: (i) string length, (ii) word frequency, (iii) regularity of grapheme‐phoneme correspondences of words, and (iv) the interaction of frequency and regularity using a bilateral lexical decision task. We observed that sex, menstrual stage, and masculinity each affected Hemispheric Specialization of the dual route variables, but did so in different ways. We posit that both hemispheres have orthographical (lexical) access as well as phonological (nonlexical) access to words. Further, we suggest that the presence of phonological processing in the right hemisphere depends on available resources and the strategies used, which are subject to individual differences. ≈ 1999 Academic Press

  • The anatomical substrates for language and Hemispheric Specialization.
    Biological Research, 1995
    Co-Authors: Francisco Aboitiz, Navarrete A, Peña M, Eugenio Rodriguez, Wolff, Eran Zaidel
    Abstract:

    Three main lines of investigation are discussed in this paper: (1) the comparison between the anatomical arrangement of the language areas and the large-scale neurocognitive cortical networks partly involved in active or working memory; (2) the relations between Hemispheric Specialization and the development of interHemispheric communication; and (3) the analysis of individual differences in brain organization for language. The hypothesis and evidence presented stem from work being performed in our laboratories.

Peter Kochunov - One of the best experts on this subject based on the ideXlab platform.

  • multi region Hemispheric Specialization differentiates human from nonhuman primate brain function
    Brain Structure & Function, 2014
    Co-Authors: Kimberley A Phillips, Reese D Mckay, Angela R Laird, Peter Kochunov
    Abstract:

    The human behavioral repertoire greatly exceeds that of nonhuman primates. Anatomical Specializations of the human brain include an enlarged neocortex and prefrontal cortex (Semendeferi et al. in Am J Phys Anthropol 114:224–241, 2001), but regional enlargements alone cannot account for these vast functional differences. Hemispheric Specialization has long believed to be a major contributing factor to such distinctive human characteristics as motor dominance, attentional control and language. Yet structural cerebral asymmetries, documented in both humans and some nonhuman primate species, are relatively minor compared to behavioral lateralization. Identifying the mechanisms that underlie these functional differences remains a goal of considerable interest. Here, we investigate the intrinsic connectivity networks in four primate species (humans, chimpanzees, baboons, and capuchin monkeys) using resting-state fMRI to evaluate the intra- and inter- Hemispheric coherences of spontaneous BOLD fluctuation. All three nonhuman primate species displayed lateralized functional networks that were strikingly similar to those observed in humans. However, only humans had multi-region lateralized networks, which provide fronto-parietal connectivity. Our results indicate that this pattern of within-hemisphere connectivity distinguishes humans from nonhuman primates.

Christian Marendaz - One of the best experts on this subject based on the ideXlab platform.

  • cerebral regions and Hemispheric Specialization for processing spatial frequencies during natural scene recognition an event related fmri study
    NeuroImage, 2004
    Co-Authors: Carole Peyrin, Monica Baciu, Christoph Segebarth, Christian Marendaz
    Abstract:

    It has been suggested that visual scene recognition is mainly based on spatial frequency (Fourier) analysis of the image. This analysis starts with processing low spatial frequencies (LSF), followed by processing high spatial frequencies (HSF). Within the framework of the spatial frequency analysis, the right/left hemisphere would be predominantly involved in LSF/HSF analysis, respectively. The aim of this event-related fMRI study was to evaluate neural correlates and Hemispheric Specialization of spatial frequency analysis during recognition of nonfiltered (NF) and filtered, either in LSF or HSF, natural scenes. Comparing LSF or NF to HSF scene recognition, significant activation was obtained within right anterior temporal cortex and right parahippocampal gyrus. As these regions are known to be involved in scene processing, we interpret this result as suggesting that scene recognition is mainly based on LSF extraction and analysis. When LSF scene was compared to HSF scene recognition, supplementary activation was obtained within the right inferior parietal lobule that likely reflects attentional modulation on spatial frequency processing. A direct interHemispheric comparison for each particular band of spatial frequencies highlighted predominance within the early visual areas (such as the middle occipital gyrus) to the right for LSF processing and to the left for HSF processing. This result provides supplementary evidence for Hemispheric Specialization at early levels of visual analysis when spatial frequencies are processed.

  • Hemispheric Specialization for spatial frequency processing in the analysis of natural scenes
    Brain and Cognition, 2003
    Co-Authors: Carole Peyrin, Alan Chauvin, Sylvie Chokron, Christian Marendaz
    Abstract:

    Experimental data coming from visual cognitive sciences suggest that visual analysis starts with a parallel extraction of different visual attributes at different scales/frequencies. Neuropsychological and functional imagery data have suggested that each hemisphere (at the level of temporo-parietal junctions-TPJ) could play a key role in spatial frequency processing: The right TPJ should predominantly be involved in low spatial frequency (LFs) analysis and the left TPJ in high spatial frequency (HFs) analysis. Nevertheless, this functional hypothesis had been inferred from data obtained when using the hierarchical form paradigm, without any explicit spatial frequency manipulation per se. The aims of this research are (i) to investigate, in healthy subjects, the Hemispheric asymmetry hypothesis with an explicit manipulation of spatial frequencies of natural scenes and (ii) to examine whether the 'precedence effect' (the relative rapidity of LFs and HFs processing) depends on the visual field of scene presentation or not. For this purpose, participants were to identify either non-filtered or LFs and HFs filtered target scene displayed either in the left, central, or right visual field. Results showed a Hemispheric Specialization for spatial frequency processing and different 'precedence effects' depending on the visual field of presentation.

Nathalie Tzouriomazoyer - One of the best experts on this subject based on the ideXlab platform.

  • revisiting human Hemispheric Specialization with neuroimaging
    Trends in Cognitive Sciences, 2013
    Co-Authors: Pierreyves Herve, Laure Zago, Laurent Petit, Bernard Mazoyer, Nathalie Tzouriomazoyer
    Abstract:

    Hemispheric Specialization (HS) is a hemisphere-dependent relationship between a cognitive, sensory, or motor function and a set of brain structures. It includes both the hosting by a given hemisphere of specialized networks that have unique functional properties and mechanisms that enable the inter-Hemispheric coordination necessary for efficient processing. Long derived from neuropsychological and behavioral observations, knowledge of HS is currently being profoundly modified by cutting-edge neuroimaging research that focuses both on the neural implementation of HS for language, visuospatial functions, and motor control/handedness across development and on the analysis of interactions between brain regions within and across hemispheres. New findings reveal the fundamental role of lateralization in the large-scale architecture of the human brain, whose ontogenesis has begun to be investigated with genetic-heritability brain mapping.

  • Hemispheric Specialization for language brain volume matters
    Brain Research, 2006
    Co-Authors: Goulven Josse, Pierreyves Herve, Bernard Mazoyer, Fabrice Crivello, Nathalie Tzouriomazoyer
    Abstract:

    Increasing brain volume may impose constraints, through longer information transfer delays, on the distributed networks supporting language. Here, we assessed the relative effects of brain volume and other putative predictors of the functional variability of perisylvian language areas, as probed with PET, during both a language comprehension and a language production task. In the case of language comprehension (story listening), a linear combination of planum temporale surface, brain volume and handedness could explain almost 60% of the functional asymmetry observed in the perisylvian area. Without brain volume, the goodness of fit was significantly decreased (39%, P < 0.05), and furthermore, the effect of handedness was not detected anymore. This was due to the fact that in our sample, left-handers (n = 12) had a significantly larger brain volume as compared to right-handers (n = 8, P = 0.03). As for language production (verb generation), brain volume and the planum temporale also played a role. However, in this case, the main predictor of functional variability was handedness, where a greater degree of right-handedness was associated with larger activation of left inferior frontal regions. Depending on the language component of interest, these results support different (yet compatible) theories on Hemispheric Specialization. Left Specialization for comprehension could be attributed to the constraints of processing speech stimuli, while a gestural origin of language is mostly supported by the relation we observed between left Specialization for production and right-handedness.

  • atypical Hemispheric Specialization for language in right handed schizophrenia patients
    Biological Psychiatry, 2005
    Co-Authors: Sonia Dollfus, Bernard Mazoyer, Annick Razafimandimby, Pascal Delamillieure, P Brazo, Marc Joliot, Nathalie Tzouriomazoyer
    Abstract:

    Background The literature suggests that schizophrenia could be related to a failure in the setting up of left hemisphere dominance for language. We sought to determine Hemispheric Specialization for language in schizophrenic patients, using functional magnetic resonance imaging. Methods Twenty-one right-handed patients with DSM-IV schizophrenia and 21 right-handed control subjects matched by age, gender, and level of education were recruited. Fractional blood oxygen level dependent (BOLD) signal variations in anatomic regions of interest were compared between groups. Functional asymmetry indices (FAIs) were calculated in a region (LANG) resulting from the merging of activated regions showing a Group × Hemisphere interaction. The FAI difference between each patient and their matched control subject was computed. Results We found lower BOLD signal changes in patients as compared with their control subjects in a network comprising areas of the left middle temporal gyrus, the left angular gyrus, and the pars triangularis of the left inferior frontal gyrus, merged to constitute LANG. The intra-pair differences of FAIs in this area showed that 76% of the patients exhibited less leftward functional asymmetry than their matched control subjects, including six patients with a rightward asymmetry. Conclusions These results demonstrated the existence of an anomaly in left hemisphere Specialization for language in schizophrenic subjects.

  • Hemispheric Specialization for language
    Brain Research Reviews, 2004
    Co-Authors: Goulven Josse, Nathalie Tzouriomazoyer
    Abstract:

    Hemispheric Specialization for language is one of the most robust findings of cognitive neuroscience. In this review, we first present the main hypotheses about the origins of this important aspect of brain organization. These theories are based in part on the main approaches to Hemispheric Specialization: studies of aphasia, anatomical asymmetries and, nowadays, neuroimaging. All these approaches uncovered a large inter-individual variability which became the bulk of research on Hemispheric Specialization. This is why, in a second part of the review, we present the main facts about inter-individual variability, trying to relate findings to the theories presented in the first part. This review focuses on neuroimaging as it has recently given important results, thanks to investigations of both anatomical and functional asymmetries in healthy subjects. Such investigations have confirmed that left-handers, especially "familial left-handers", are more likely to have an atypical pattern of Hemispheric Specialization for language. Differences between men and women seem less evident although a less marked Hemispheric Specialization for language was depicted in women. As for the supposed relationship between anatomical and functional asymmetries, it has been shown that the size of the left (not the right) planum temporale could explain part of the variability of left Hemispheric Specialization for language comprehension. Taken as a whole, findings seem to vary with language tasks and brain regions, therefore showing that Hemispheric Specialization for language is multi-dimensional. This is not accounted for in the existing models of Hemispheric Specialization.

Philip S Holzman - One of the best experts on this subject based on the ideXlab platform.

  • intact Hemispheric Specialization for spatial and shape working memory in schizophrenia
    Schizophrenia Research, 2005
    Co-Authors: Dara S Manoach, Nathan S White, Kristen A Lindgren, Stephan Heckers, Michael J Coleman, Stephanie Dubal, Donald C Goff, Philip S Holzman
    Abstract:

    OBJECTIVE: Using functional MRI, we investigated whether, like healthy subjects, patients with schizophrenia show a relative Hemispheric Specialization in ventrolateral prefrontal cortex (PFC) for spatial and shape working memory (WM). We hypothesized that reduced Specialization in schizophrenia would reflect a failure to adopt optimal domain-specific strategies and would contribute to WM deficits. METHODS: Twelve healthy subjects and 16 schizophrenia patients performed spatial and shape WM tasks and a non-WM control task. Direct comparisons of the spatial and shape WM tasks assessed Specialization. RESULTS: Despite deficient WM performance, both patients and controls showed a relative Hemispheric Specialization in ventrolateral PFC for spatial (right) and shape (left) WM and did not differ in this regard. CONCLUSIONS: The finding of intact Hemispheric Specialization in ventrolateral PFC suggests that patients employ the same domain-specific strategies as healthy subjects during spatial and shape WM. Rather than reflecting a failure to adopt the optimal strategy, we hypothesize that WM deficits in schizophrenia reflect impairments of executive processes that are required for WM performance regardless of domain. These processes are associated with activity in the dorsolateral PFC, a region that has been repeatedly implicated in studies of WM.

  • Intact Hemispheric Specialization for spatial and shape working memory in schizophrenia
    Schizophrenia Research, 2005
    Co-Authors: Dara S Manoach, Nathan S White, Kristen A Lindgren, Stephan Heckers, Michael J Coleman, Stephanie Dubal, Donald C Goff, Philip S Holzman
    Abstract:

    Abstract Objective Using functional MRI, we investigated whether, like healthy subjects, patients with schizophrenia show a relative Hemispheric Specialization in ventrolateral prefrontal cortex (PFC) for spatial and shape working memory (WM). We hypothesized that reduced Specialization in schizophrenia would reflect a failure to adopt optimal domain-specific strategies and would contribute to WM deficits. Methods Twelve healthy subjects and 16 schizophrenia patients performed spatial and shape WM tasks and a non-WM control task. Direct comparisons of the spatial and shape WM tasks assessed Specialization. Results Despite deficient WM performance, both patients and controls showed a relative Hemispheric Specialization in ventrolateral PFC for spatial (right) and shape (left) WM and did not differ in this regard. Conclusions The finding of intact Hemispheric Specialization in ventrolateral PFC suggests that patients employ the same domain-specific strategies as healthy subjects during spatial and shape WM. Rather than reflecting a failure to adopt the optimal strategy, we hypothesize that WM deficits in schizophrenia reflect impairments of executive processes that are required for WM performance regardless of domain. These processes are associated with activity in the dorsolateral PFC, a region that has been repeatedly implicated in studies of WM.