Diminished neural adaptation during implicit learning in autism

Neuroimaging studies have shown evidence of disrupted neural adaptation during learning in individuals with autism spectrum disorder (ASD) in several types of tasks, potentially stemming from frontal-posterior cortical underconnectivity (Schipul et al., 2012). The aim of the current study was to examine neural adaptations in an implicit learning task that entails participation of frontal and posterior regions. Sixteen high-functioning adults with ASD and sixteen neurotypical control participants were trained on and performed an implicit dot pattern prototype learning task in a functional magnetic resonance imaging (fMRI) session. During the preliminary exposure to the type of implicit prototype learning task later to be used in the scanner, the ASD participants took longer than the neurotypical group to learn the task, demonstrating altered implicit learning in ASD. After equating task structure learning, the two groups’ brain activation differed during their learning of a new prototype in the subsequent scanning session. The main findings indicated that neural adaptations in a distributed task network were reduced in the ASD group, relative to the neurotypical group, and were related to ASD symptom severity. Functional connectivity was reduced and did not change as much during learning for the ASD group, and was related to ASD symptom severity. These findings suggest that individuals with ASD show altered neural adaptations during learning, as seen in both activation and functional connectivity measures. This finding suggests why many real-world implicit learning situations may pose special challenges for ASD

Inter-Regional Brain Communication and Its Disturbance in Autism

In this review article, we summarize recent progress toward understanding disturbances in functional and anatomical brain connectivity in autism. Autism is a neurodevelopmental disorder affecting language, social interaction, and repetitive behaviors. Recent studies have suggested that limitations of frontal–posterior brain connectivity in autism underlie the varied set of deficits associated with this disorder. Specifically, the underconnectivity theory of autism postulates that individuals with autism have a reduced communication bandwidth between frontal and posterior cortical areas, which constrains the psychological processes that rely on the integrated functioning of frontal and posterior brain networks. This review summarizes the recent findings of reduced frontal–posterior functional connectivity (synchronization) in autism in a wide variety of high-level tasks, focusing on data from functional magnetic resonance imaging studies. It also summarizes the findings of disordered anatomical connectivity in autism, as measured by a variety of techniques, including distribution of white matter volumes and diffusion tensor imaging. We conclude with a discussion of the implications of these findings for autism and future directions for this line of research

Eye Tracking Reveals Impaired Attentional Disengagement Associated with Sensory Response Patterns in Children with Autism

This study used a gap-overlap paradigm to examine the impact of distractor salience and temporal overlap on the ability to disengage and orient attention in 50 children (4–13 years) with ASD, DD and TD, and associations between attention and sensory response patterns. Results revealed impaired disengagement and orienting accuracy in ASD. Disengagement was impaired across all groups during temporal overlap for dynamic stimuli compared to static, but only ASD showed slower disengagement from multimodal relative to unimodal dynamic stimuli. Attentional disengagement had differential associations with distinct sensory response patterns in ASD and DD. Atypical sensory processing and temporal binding appear to be intertwined with development of disengagement in ASD, but longitudinal studies are needed to unravel causal pathways

Attenuated Auditory Event-Related Potentials and Associations with Atypical Sensory Response Patterns in Children with Autism

Neurobiological underpinnings of unusual sensory features in individuals with autism are unknown. Event-related potentials (ERPs) elicited by task-irrelevant sounds were used to elucidate neural correlates of auditory processing and associations with three common sensory response patterns (hyperresponsiveness; hyporesponsiveness; sensory seeking). Twenty-eight children with autism and 39 typically developing children (4–12 year-olds) completed an auditory oddball paradigm. Results revealed marginally attenuated P1 and N2 to standard tones and attenuated P3a to novel sounds in autism versus controls. Exploratory analyses suggested that within the autism group, attenuated N2 and P3a amplitudes were associated with greater sensory seeking behaviors for specific ranges of P1 responses. Findings suggest that attenuated early sensory as well as later attention-orienting neural responses to stimuli may underlie selective sensory features via complex mechanisms

Inter-regional brain communication and its disturbance in autism

Department of Psycholog

Auditory event-related potentials and associations with sensory patterns in children with autism spectrum disorder, developmental delay, and typical development

Atypical sensory response patterns are common in children with autism and developmental delay. Expanding on previous work, this observational EEG study assessed auditory event-related potentials (ERPs) and their associations with clinically evaluated sensory response patterns in children with autism spectrum disorder (ASD; n=28), developmental delay (DD; n=17), and typical development (TD; n=39). Attention-orienting P3a responses were attenuated in ASD relative to both DD and TD, but early sensory N2 responses were attenuated in both ASD and DD relative to TD. Attenuated ERPs involving N2 or P3a components, or a P1×N2 interaction, were related to more severe hyporesponsive or sensory seeking response patterns across children with ASD and DD. Thus, although attentional disruptions may be unique to ASD, sensory disruptions appear across developmental delay and are associated with atypical sensory behaviors

Distinctive neural processes during learning in autism

Department of Psycholog

The local, global, and neural aspects of visuospatial processing in autism spectrum disorders

Behavioral studies have documented a relative advantage in some aspects of visuospatial cognition in autism although it is not consistently found in higher functioning individuals with autism. The purpose of this functional neuroimaging study was to examine the neural activity in high functioning individuals with autism while they performed a block design task that systematically varied with regard to whether a global pattern was present. Participants were 14 adults with high-functioning autism and 14 age and IQ matched typical controls. The task was to identify a missing block in target figures which had either an obvious global shape or was an arbitrary array of blocks. Behavioral results showed intact, but not superior, performance in our participants with autism. A key group difference was that the participants with autism showed reliably greater activation in occipital and parietal regions in both tasks suggesting an increased reliance of the autism group on posterior brain areas to mediate visuospatial tasks. Thus, increased reliance on relatively posterior brain regions in itself may not guarantee superior performance as seen in the present study. © 2013 Elsevier Ltd

Electrophysiological Correlates of Aberrant Motivated Attention and Salience Processing in Unaffected Relatives of Schizophrenia Patients

Patients with schizophrenia (SCZ) exhibit debilitating deficits in attention and affective processing, which are often resistant to treatment and associated with poor functional outcomes. Impaired orientation to task-relevant target information has been indexed by diminished P3b event-related potentials in patients, as well as their unaffected first-degree relatives, suggesting that P3b may be a vulnerability marker for schizophrenia. Despite intact affective valence processing, patients are unable to employ cognitive change strategies to reduce electrophysiological responses to aversive stimuli. Less is known about the attentional processing of emotionally salient task-irrelevant information in patients and unaffected first-degree relatives. The goal of the present study was to examine the neural correlates of salience processing, as indexed by the late positive potential (LPP), during the processing of emotionally salient distractor stimuli in 31 patients with SCZ, 28 first-degree relatives, and 47 control participants using an oddball paradigm. Results indicated that despite intact novelty detection (P3a), both SCZ and first-degree relatives demonstrated deficiencies in attentional processing, reflected in attenuated target-P3b, and aberrant motivated attention, with reduced early-LPP amplitudes for aversive stimuli relative to controls. First-degree relatives revealed a unique enhancement of the late-LPP response, possibly underlying an exaggerated evaluation of salient information and a compensatory engagement of neural circuitry. Furthermore, reduced early-LPP and target-P3b amplitudes were associated with enhanced symptom severity. These findings suggest that, in addition to P3b, LPP may be useful for monitoring clinical state. Future studies will explore the value of P3 and LPP responses as vulnerability markers for early detection and prediction of psychopathology. ? EEG and Clinical Neuroscience Society (ECNS) 2015