Lateralized Response Timing Deficits in Autism

Center for Cognitive Medicine, University of Illinois at Chicago, Pittsburgh, Pennsylvania, USA.
Biological psychiatry (Impact Factor: 10.26). 03/2009; 66(4):393-7. DOI: 10.1016/j.biopsych.2009.01.008
Source: PubMed


Procedural learning is an implicit process in which a behavioral response is refined through repeated performance. Neural systems supporting this cognitive process include specific frontostriatal systems responsible for the preparation and timing of planned motor responses. Evaluating performance on procedural learning tasks can provide unique information about neurodevelopmental disorders in which frontostriatal disturbances have been reported, such as autism.
Fifty-two individuals with autism and 54 age-, IQ-, and gender-matched healthy individuals performed an oculomotor serial reaction time task and a sensorimotor control task.
Whereas the rate of procedural learning and the precision of planned motor responses were unimpaired in autism, a lateralized alteration in the ability to time predictive responses was observed. Rightward saccadic responses were speeded in individuals with autism relative to healthy control subjects.
Speeded rightward predictive saccades suggest atypical functioning of left hemisphere striatal chronometric systems in autism.

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    • "This rightward bias is thought to result from hyperexcitability of intact left hemispheric cortex due to its reduced inhibition by the damaged right hemisphere (Koch et al., 2008, 2013). Interestingly, abnormally speeded saccades to the right have been reported also in adults with autism (D'Cruz et al., 2009), thus indirectly supporting the hypothesis about the right-hemispheric deficit. "
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    ABSTRACT: The extended phenotype of autism spectrum disorders (ASD) includes a combination of arousal regulation problems, sensory modulation difficulties, and attention re-orienting deficit. A slow and inefficient re-orienting to stimuli that appear outside of the attended sensory stream is thought to be especially detrimental for social functioning. Event-related potentials (ERPs) and magnetic fields (ERFs) may help to reveal which processing stages underlying brain response to unattended but salient sensory event are affected in individuals with ASD. Previous research focusing on two sequential stages of the brain response-automatic detection of physical changes in auditory stream, indexed by mismatch negativity (MMN), and evaluation of stimulus novelty, indexed by P3a component,-found in individuals with ASD either increased, decreased, or normal processing of deviance and novelty. The review examines these apparently conflicting results, notes gaps in previous findings, and suggests a potentially unifying hypothesis relating the dampened responses to unattended sensory events to the deficit in rapid arousal process. Specifically, "sensory gating" studies focused on pre-attentive arousal consistently demonstrated that brain response to unattended and temporally novel sound in ASD is already affected at around 100 ms after stimulus onset. We hypothesize that abnormalities in nicotinic cholinergic arousal pathways, previously reported in individuals with ASD, may contribute to these ERP/ERF aberrations and result in attention re-orienting deficit. Such cholinergic dysfunction may be present in individuals with ASD early in life and can influence both sensory processing and attention re-orienting behavior. Identification of early neurophysiological biomarkers for cholinergic deficit would help to detect infants "at risk" who can potentially benefit from particular types of therapies or interventions.
    Frontiers in Human Neuroscience 02/2014; 8(1):34. DOI:10.3389/fnhum.2014.00034 · 2.99 Impact Factor
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    • "In contrast, lateral differences were absent in the ASD group. All of these effects support the notion of atypical functional brain organization [111], [112] in ASD participants during social stimuli processing. "
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    ABSTRACT: Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition clinically characterized by social interaction and communication difficulties. To date, the majority of research efforts have focused on brain mechanisms underlying the deficits in interpersonal social cognition associated with ASD. Recent empirical and theoretical work has begun to reveal evidence for a reduced or even absent self-preference effect in patients with ASD. One may hypothesize that this is related to the impaired attentional processing of self-referential stimuli. The aim of our study was to test this hypothesis. We investigated the neural correlates of face and name detection in ASD. Four categories of face/name stimuli were used: own, close-other, famous, and unknown. Event-related potentials were recorded from 62 electrodes in 23 subjects with ASD and 23 matched control subjects. P100, N170, and P300 components were analyzed. The control group clearly showed a significant self-preference effect: higher P300 amplitude to the presentation of own face and own name than to the close-other, famous, and unknown categories, indicating preferential attentional engagement in processing of self-related information. In contrast, detection of both own and close-other's face and name in the ASD group was associated with enhanced P300, suggesting similar attention allocation for self and close-other related information. These findings suggest that attention allocation in the ASD group is modulated by the personal significance factor, and that the self-preference effect is absent if self is compared to close-other. These effects are similar for physical and non-physical aspects of the autistic self. In addition, lateralization of face and name processing is attenuated in ASD, suggesting atypical brain organization.
    PLoS ONE 01/2014; 9(1):e86020. DOI:10.1371/journal.pone.0086020 · 3.23 Impact Factor
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    • "When performing tasks of executive functioning (for example, Go/No-go and Stroop tests), high-functioning adults with ASD had significantly increased activation restricted to the left hemisphere [114]. Left-hemisphere dysfunction has also been identified in smooth pursuit eye movements in individuals with ASD [115], as have left-lateralized alterations during an oculomotor serial reaction time task [116]. "
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    ABSTRACT: Autism spectrum disorders (ASD) are a group of complex and heterogeneous developmental disorders involving multiple neural system dysfunctions. In an effort to understand neurophysiological substrates, identify etiopathophysiologically distinct subgroups of patients, and track outcomes of novel treatments with translational biomarkers, EEG (electroencephalography) studies offer a promising research strategy in ASD. Resting-state EEG studies of ASD suggest a U-shaped profile of electrophysiological power alterations, with excessive power in low-frequency and high-frequency bands, abnormal functional connectivity, and enhanced power in the left hemisphere of the brain. In this review, we provide a summary of recent findings, discuss limitations in available research that may contribute to inconsistencies in the literature, and offer suggestions for future research in this area for advancing the understanding of ASD.
    Journal of Neurodevelopmental Disorders 09/2013; 5(1):24. DOI:10.1186/1866-1955-5-24 · 3.27 Impact Factor
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