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Special treatment of prediction errors in autism spectrum disorder. Neuropsychologia 2021; 163:108070. [PMID: 34695420 DOI: 10.1016/j.neuropsychologia.2021.108070] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 09/09/2021] [Accepted: 10/21/2021] [Indexed: 12/23/2022]
Abstract
For autistic individuals, sensory stimulation can be experienced as overwhelming. Models of predictive coding postulate that cortical mechanisms disamplify predictable information and amplify prediction errors that surpass a defined precision level. In autism, the neuronal processing is putting an inflexibly high precision on prediction errors according to the HIPPEA theory (High, Inflexible Precision of Prediction Errors in Autism). We used an apparent motion paradigm to test this prediction. In apparent motion paradigms, the illusory motion of an object creates a prediction about where and when an internally generated token would be moving along the apparent motion trace. This illusion facilitates the perception of a flashing stimulus (target) appearing in-time with the apparent motion token and is perceived as a predictable event (predictable target). In contrast, a flashing stimulus appearing out-of-time with the apparent motion illusion is an unpredictable target that is less often detected even though it produces a prediction error signal. If a prediction error does not surpass a given precision threshold the stimulation event is discounted and therefore less often detected than predictable tokens. In autism, the precision threshold is lower and the same prediction errors (unpredictable target) triggers a detection similar to that of a predictable flash stimulus. To test this hypothesis, we recruited 11 autistic males and 9 neurotypical matched controls. The participants were tasked to detect flashing stimuli placed on an apparent motion trace either in-time or out-of-time with the apparent motion illusion. Descriptively, 66% (6/9) of neurotypical and 64% (7/11) of autistic participants were better at detecting predictable targets. The prediction established by illusory motion appears to assist autistic and neurotypical individuals equally in the detection of predictable over unpredictable targets. Importantly, 55% (6/11) of autistic participants had faster responses for unpredictable targets, whereas only 22% (2/9) of neurotypicals had faster responses to unpredictable compared to predictable targets. Hence, these tentative results suggest that for autistic participants, unpredictable targets produce an above threshold prediction error, which leads to faster response. This difference in unpredictable target detection can be encapsulated under the HIPPEA theory, suggesting that precision setting could be aberrant in autistic individuals with respect to prediction errors. These tentative results should be considered in light of the small sample. For this reason, we provide the full set of materials necessary to replicate and extend the results.
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Predictive action perception from explicit intention information in autism. Psychon Bull Rev 2021; 28:1556-1566. [PMID: 34027620 DOI: 10.3758/s13423-021-01941-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2021] [Indexed: 01/02/2023]
Abstract
Social difficulties in autism spectrum disorder (ASD) may originate from a reduced top-down modulation of sensory information that prevents the spontaneous attribution of intentions to observed behaviour. However, although people with autism are able to explicitly reason about others' mental states, the effect of abstract intention information on perceptual processes has remained untested. ASD participants (n = 23) and a neurotypical (NT) control group (n = 23) observed a hand either reaching for an object or withdrawing from it. Prior to action onset, the participant either instructed the actor to "Take it" or "Leave it", or heard the actor state "I'll take it" or "I'll leave it", which provided an explicit intention that was equally likely to be congruent or incongruent with the subsequent action. The hand disappeared before completion of the action, and participants reported the last seen position of the tip of the index finger by touching the screen. NT participants exhibited a predictive bias in response to action direction (reaches perceived nearer the object, withdrawals perceived farther away), and in response to prior knowledge of the actor's intentions (nearer the object after "Take it", farther away after "Leave it"). However, ASD participants exhibited a predictive perceptual bias only in response to the explicit intentions, but not in response to the motion of the action itself. Perception in ASD is not immune from top-down modulation. However, the information must be explicitly presented independently from the stimulus itself, and not inferred from cues inherent in the stimulus.
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Ghiani A, Maniglia M, Battaglini L, Melcher D, Ronconi L. Binding Mechanisms in Visual Perception and Their Link With Neural Oscillations: A Review of Evidence From tACS. Front Psychol 2021; 12:643677. [PMID: 33828509 PMCID: PMC8019716 DOI: 10.3389/fpsyg.2021.643677] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/22/2021] [Indexed: 12/14/2022] Open
Abstract
Neurophysiological studies in humans employing magneto- (MEG) and electro- (EEG) encephalography increasingly suggest that oscillatory rhythmic activity of the brain may be a core mechanism for binding sensory information across space, time, and object features to generate a unified perceptual representation. To distinguish whether oscillatory activity is causally related to binding processes or whether, on the contrary, it is a mere epiphenomenon, one possibility is to employ neuromodulatory techniques such as transcranial alternating current stimulation (tACS). tACS has seen a rising interest due to its ability to modulate brain oscillations in a frequency-dependent manner. In the present review, we critically summarize current tACS evidence for a causal role of oscillatory activity in spatial, temporal, and feature binding in the context of visual perception. For temporal binding, the emerging picture supports a causal link with the power and the frequency of occipital alpha rhythms (8-12 Hz); however, there is no consistent evidence on the causal role of the phase of occipital tACS. For feature binding, the only study available showed a modulation by occipital alpha tACS. The majority of studies that successfully modulated oscillatory activity and behavioral performance in spatial binding targeted parietal areas, with the main rhythms causally linked being the theta (~7 Hz) and beta (~18 Hz) frequency bands. On the other hand, spatio-temporal binding has been directly modulated by parieto-occipital gamma (~40-60 Hz) and alpha (10 Hz) tACS, suggesting a potential role of cross-frequency coupling when binding across space and time. Nonetheless, negative or partial results have also been observed, suggesting methodological limitations that should be addressed in future research. Overall, the emerging picture seems to support a causal role of brain oscillations in binding processes and, consequently, a certain degree of plasticity for shaping binding mechanisms in visual perception, which, if proved to have long lasting effects, can find applications in different clinical populations.
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Affiliation(s)
- Andrea Ghiani
- Department of General Psychology, University of Padua, Padua, Italy
| | - Marcello Maniglia
- Department of Psychology, University of California, Riverside, Riverside, CA, United States
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Luca Battaglini
- Department of General Psychology, University of Padua, Padua, Italy
- Neuro Vis.U.S. Laboratory, University of Padua, Padua, Italy
- Department of Physics and Astronomy "Galileo Galilei", University of Padua, Padua, Italy
| | - David Melcher
- Center for Mind/Brain Sciences and Department of Psychology and Cognitive Science, University of Trento, Trento, Italy
- Psychology Program, Division of Science, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Luca Ronconi
- School of Psychology, Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, Istituto di Ricovero e Cura a Carattere Scientifico, San Raffaele Hospital, Milan, Italy
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Helfrich RF, Knepper H, Nolte G, Sengelmann M, König P, Schneider TR, Engel AK. Spectral fingerprints of large-scale cortical dynamics during ambiguous motion perception. Hum Brain Mapp 2018; 37:4099-4111. [PMID: 27347668 DOI: 10.1002/hbm.23298] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 06/13/2016] [Accepted: 06/20/2016] [Indexed: 11/08/2022] Open
Abstract
Ambiguous stimuli have been widely used to study the neuronal correlates of consciousness. Recently, it has been suggested that conscious perception might arise from the dynamic interplay of functionally specialized but widely distributed cortical areas. While previous research mainly focused on phase coupling as a correlate of cortical communication, more recent findings indicated that additional coupling modes might coexist and possibly subserve distinct cortical functions. Here, we studied two coupling modes, namely phase and envelope coupling, which might differ in their origins, putative functions and dynamics. Therefore, we recorded 128-channel EEG while participants performed a bistable motion task and utilized state-of-the-art source-space connectivity analysis techniques to study the functional relevance of different coupling modes for cortical communication. Our results indicate that gamma-band phase coupling in extrastriate visual cortex might mediate the integration of visual tokens into a moving stimulus during ambiguous visual stimulation. Furthermore, our results suggest that long-range fronto-occipital gamma-band envelope coupling sustains the horizontal percept during ambiguous motion perception. Additionally, our results support the idea that local parieto-occipital alpha-band phase coupling controls the inter-hemispheric information transfer. These findings provide correlative evidence for the notion that synchronized oscillatory brain activity reflects the processing of sensory input as well as the information integration across several spatiotemporal scales. The results indicate that distinct coupling modes are involved in different cortical computations and that the rich spatiotemporal correlation structure of the brain might constitute the functional architecture for cortical processing and specific multi-site communication. Hum Brain Mapp 37:4099-4111, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Randolph F Helfrich
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany. .,Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California.
| | - Hannah Knepper
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany
| | - Guido Nolte
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany
| | - Malte Sengelmann
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany
| | - Peter König
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany.,Institute of Cognitive Science, University of Osnabrück, Osnabrück, 49069, Germany
| | - Till R Schneider
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany
| | - Andreas K Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany
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Dysfunction of sensory oscillations in Autism Spectrum Disorder. Neurosci Biobehav Rev 2016; 68:848-861. [PMID: 27451342 DOI: 10.1016/j.neubiorev.2016.07.016] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/31/2016] [Accepted: 07/16/2016] [Indexed: 11/21/2022]
Abstract
Autism Spectrum Disorder (ASD) is a highly prevalent developmental disability characterized by deficits in social communication and interaction, restricted interests, and repetitive behaviors. Recently, anomalous sensory and perceptual function has gained an increased level of recognition as an important feature of ASD. A specific impairment in the ability to integrate information across brain networks has been proposed to contribute to these disruptions. A crucial mechanism for these integrative processes is the rhythmic synchronization of neuronal excitability across neural populations; collectively known as oscillations. In ASD there is believed to be a deficit in the ability to efficiently couple functional neural networks using these oscillations. This review discusses evidence for disruptions in oscillatory synchronization in ASD, and how disturbance of this neural mechanism contributes to alterations in sensory and perceptual function. The review also frames oscillatory data from the perspective of prevailing neurobiologically-inspired theories of ASD.
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Perceptual Integration Deficits in Autism Spectrum Disorders Are Associated with Reduced Interhemispheric Gamma-Band Coherence. J Neurosci 2016; 35:16352-61. [PMID: 26674862 DOI: 10.1523/jneurosci.1442-15.2015] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The integration of visual details into a holistic percept is essential for object recognition. This integration has been reported as a key deficit in patients with autism spectrum disorders (ASDs). The weak central coherence account posits an altered disposition to integrate features into a coherent whole in ASD. Here, we test the hypothesis that such weak perceptual coherence may be reflected in weak neural coherence across different cortical sites. We recorded magnetoencephalography from 20 adult human participants with ASD and 20 matched controls, who performed a slit-viewing paradigm, in which objects gradually passed behind a vertical or horizontal slit so that only fragments of the object were visible at any given moment. Object recognition thus required perceptual integration over time and, in case of the horizontal slit, also across visual hemifields. ASD participants were selectively impaired in the horizontal slit condition, indicating specific difficulties in long-range synchronization between the hemispheres. Specifically, the ASD group failed to show condition-related enhancement of imaginary coherence between the posterior superior temporal sulci in both hemispheres during horizontal slit-viewing in contrast to controls. Moreover, local synchronization reflected in occipitocerebellar beta-band power was selectively reduced for horizontal compared with vertical slit-viewing in ASD. Furthermore, we found disturbed connectivity between right posterior superior temporal sulcus and left cerebellum. Together, our results suggest that perceptual integration deficits co-occur with specific patterns of abnormal global and local synchronization in ASD. SIGNIFICANCE STATEMENT The weak central coherence account proposes a tendency of individuals with autism spectrum disorders (ASDs) to focus on details at the cost of an integrated coherent whole. Here, we provide evidence, at the behavioral and the neural level, that visual integration in object recognition is impaired in ASD, when details had to be integrated across both visual hemifields. We found enhanced interhemispheric gamma-band coherence in typically developed participants when communication between cortical hemispheres was required by the task. Importantly, participants with ASD failed to show this enhanced coherence between bilateral posterior superior temporal sulci. The findings suggest that visual integration is disturbed at the local and global synchronization scale, which might bear implications for object recognition in ASD.
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Helfrich RF, Knepper H, Nolte G, Strüber D, Rach S, Herrmann CS, Schneider TR, Engel AK. Selective modulation of interhemispheric functional connectivity by HD-tACS shapes perception. PLoS Biol 2014; 12:e1002031. [PMID: 25549264 PMCID: PMC4280108 DOI: 10.1371/journal.pbio.1002031] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 11/17/2014] [Indexed: 11/18/2022] Open
Abstract
Oscillatory neuronal synchronization between cortical areas has been suggested to constitute a flexible mechanism to coordinate information flow in the human cerebral cortex. However, it remains unclear whether synchronized neuronal activity merely represents an epiphenomenon or whether it is causally involved in the selective gating of information. Here, we combined bilateral high-density transcranial alternating current stimulation (HD-tACS) at 40 Hz with simultaneous electroencephalographic (EEG) recordings to study immediate electrophysiological effects during the selective entrainment of oscillatory gamma-band signatures. We found that interhemispheric functional connectivity was modulated in a predictable, phase-specific way: In-phase stimulation enhanced synchronization, anti-phase stimulation impaired functional coupling. Perceptual correlates of these connectivity changes were found in an ambiguous motion task, which strongly support the functional relevance of long-range neuronal coupling. Additionally, our results revealed a decrease in oscillatory alpha power in response to the entrainment of gamma band signatures. This finding provides causal evidence for the antagonistic role of alpha and gamma oscillations in the parieto-occipital cortex and confirms that the observed gamma band modulations were physiological in nature. Our results demonstrate that synchronized cortical network activity across several spatiotemporal scales is essential for conscious perception and cognition.
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Affiliation(s)
- Randolph F Helfrich
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hannah Knepper
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Guido Nolte
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Daniel Strüber
- Experimental Psychology Lab, Center for Excellence 'Hearing4all', European Medical School, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Stefan Rach
- Experimental Psychology Lab, Center for Excellence 'Hearing4all', European Medical School, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany; Department of Epidemiological Methods and Etiologic Research, Leibniz Institute for Prevention Research and Epidemiology - BIPS, Bremen, Germany
| | - Christoph S Herrmann
- Experimental Psychology Lab, Center for Excellence 'Hearing4all', European Medical School, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Till R Schneider
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andreas K Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Gómez C, Lizier JT, Schaum M, Wollstadt P, Grützner C, Uhlhaas P, Freitag CM, Schlitt S, Bölte S, Hornero R, Wibral M. Reduced predictable information in brain signals in autism spectrum disorder. Front Neuroinform 2014; 8:9. [PMID: 24592235 PMCID: PMC3924322 DOI: 10.3389/fninf.2014.00009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 01/23/2014] [Indexed: 01/29/2023] Open
Abstract
Autism spectrum disorder (ASD) is a common developmental disorder characterized by communication difficulties and impaired social interaction. Recent results suggest altered brain dynamics as a potential cause of symptoms in ASD. Here, we aim to describe potential information-processing consequences of these alterations by measuring active information storage (AIS)-a key quantity in the theory of distributed computation in biological networks. AIS is defined as the mutual information between the past state of a process and its next measurement. It measures the amount of stored information that is used for computation of the next time step of a process. AIS is high for rich but predictable dynamics. We recorded magnetoencephalography (MEG) signals in 10 ASD patients and 14 matched control subjects in a visual task. After a beamformer source analysis, 12 task-relevant sources were obtained. For these sources, stationary baseline activity was analyzed using AIS. Our results showed a decrease of AIS values in the hippocampus of ASD patients in comparison with controls, meaning that brain signals in ASD were either less predictable, reduced in their dynamic richness or both. Our study suggests the usefulness of AIS to detect an abnormal type of dynamics in ASD. The observed changes in AIS are compatible with Bayesian theories of reduced use or precision of priors in ASD.
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Affiliation(s)
- Carlos Gómez
- Biomedical Engineering Group, E. T. S. Ingenieros de Telecomunicación, University of ValladolidValladolid, Spain
| | - Joseph T. Lizier
- Commonwealth Scientific and Industrial Research Organisation, Computational InformaticsMarsfield, NSW, Australia
| | - Michael Schaum
- MEG Unit, Brain Imaging Center, Johann Wolfgang Goethe UniversityFrankfurt am Main, Germany
| | - Patricia Wollstadt
- MEG Unit, Brain Imaging Center, Johann Wolfgang Goethe UniversityFrankfurt am Main, Germany
| | - Christine Grützner
- Department of Neurophysiology, Max-Planck Institute for Brain ResearchFrankfurt am Main, Germany
| | - Peter Uhlhaas
- Institute of Neuroscience and Psychology, University of GlasgowGlasgow, UK
| | - Christine M. Freitag
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Johann Wolfgang Goethe UniversityFrankfurt am Main, Germany
| | - Sabine Schlitt
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Johann Wolfgang Goethe UniversityFrankfurt am Main, Germany
| | - Sven Bölte
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Johann Wolfgang Goethe UniversityFrankfurt am Main, Germany
| | - Roberto Hornero
- Biomedical Engineering Group, E. T. S. Ingenieros de Telecomunicación, University of ValladolidValladolid, Spain
| | - Michael Wibral
- MEG Unit, Brain Imaging Center, Johann Wolfgang Goethe UniversityFrankfurt am Main, Germany
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Kuzmanovic B, Schilbach L, Georgescu AL, Kockler H, Santos NS, Shah NJ, Bente G, Fink GR, Vogeley K. Dissociating animacy processing in high-functioning autism: neural correlates of stimulus properties and subjective ratings. Soc Neurosci 2014; 9:309-25. [PMID: 24512520 DOI: 10.1080/17470919.2014.886618] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
When movements indicate meaningful actions, even nonbiological objects induce the impression of "having a mind" or animacy. This basic social ability was investigated in adults with high-functioning autism (HFA, n = 13, and matched controls, n = 13) by systematically varying motion properties of simple geometric shapes. Critically, trial-by-trial variations of (1) motion complexity of stimuli, and of (2) participants' individual animacy ratings were separately correlated with neural activity to dissociate cognitive strategies relying more closely on stimulus analysis vs. subjective experience. Increasing motion complexity did not yield any significant group differences, and in both groups, it correlated with neural activity in regions involved in perceptual and evaluative processing, including the ventral medial prefrontal cortex (mPFC), superior temporal gyrus (STG) and posterior cingulate cortex (PCC). In contrast, although there were no significant behavioral differences between the groups, increasing animacy ratings correlated with neural activity in the insula, STG, amygdala, dorsal mPFC and PCC more strongly in controls than in HFA. These results indicate that in HFA the evaluation of stimulus properties cuing for animacy is intact, while increasing subjective ratings do not seem to be robustly related to social processing, including spontaneous mental state inferences and experience of salience.
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Affiliation(s)
- Bojana Kuzmanovic
- a Institute of Neuroscience and Medicine-Ethics in the Neurosciences (INM-8) , Research Center Juelich , Juelich , Germany
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Fiebelkorn IC, Foxe JJ, McCourt ME, Dumas KN, Molholm S. Atypical category processing and hemispheric asymmetries in high-functioning children with autism: revealed through high-density EEG mapping. Cortex 2012; 49:1259-67. [PMID: 22652240 DOI: 10.1016/j.cortex.2012.04.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 04/01/2012] [Accepted: 04/17/2012] [Indexed: 11/19/2022]
Abstract
Behavioral evidence for an impaired ability to group objects based on similar physical or semantic properties in autism spectrum disorders (ASD) has been mixed. Here, we recorded brain activity from high-functioning children with ASD as they completed a visual-target detection task. We then assessed the extent to which object-based selective attention automatically generalized from targets to non-target exemplars from the same well-known object class (e.g., dogs). Our results provide clear electrophysiological evidence that children with ASD (N=17, aged 8-13 years) process the similarity between targets (e.g., a specific dog) and same-category non-targets (SCNT) (e.g., another dog) to a lesser extent than do their typically developing (TD) peers (N=21). A closer examination of the data revealed striking hemispheric asymmetries that were specific to the ASD group. These findings align with mounting evidence in the autism literature of anatomic underconnectivity between the cerebral hemispheres. Years of research in individuals with TD have demonstrated that the left hemisphere (LH) is specialized toward processing local (or featural) stimulus properties and the right hemisphere (RH) toward processing global (or configural) stimulus properties. We therefore propose a model where a lack of communication between the hemispheres in ASD, combined with typical hemispheric specialization, is a root cause for impaired categorization and the oft-observed bias to process local over global stimulus properties.
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Affiliation(s)
- Ian C Fiebelkorn
- The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center (CERC), Department of Pediatrics, Albert Einstein College of Medicine, Van Etten Building, 1C, Bronx, NY, USA
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