I'm a cognitive/social neuroscientist, with training in clinical neuropsychology and cognitive neuroscience. I use neuroimaging tools (EEG, ERPs, fMRI) to examine social cognition in typical and atypical development.
Neuroimaging studies have revealed atypical activation during language and executive tasks in ind... more Neuroimaging studies have revealed atypical activation during language and executive tasks in individuals with autism spectrum disorders (ASD). However, the spatiotemporal stages of processing associated with these dysfunctions remain poorly understood. Using an anatomically constrained magnetoencephalography approach, we examined event-related theta oscillations during a double-duty lexical decision task that combined demands on lexico-semantic processing and executive functions. Relative to typically developing peers, high-functioning adolescents with ASD had lower performance accuracy on trials engaging selective semantic retrieval and cognitive control. They showed an early overall theta increase in the left fusiform cortex followed by greater activity in the left-lateralized temporal (starting at ~250 ms) and frontal cortical areas (after ~450 ms) known to contribute to language processing. During response preparation and execution, the ASD group exhibited elevated theta in the...
Although a growing literature highlights sex differences in autism spectrum disorder clinical pre... more Although a growing literature highlights sex differences in autism spectrum disorder clinical presentation, less is known about female variants at the neural level. We investigated sex-related patterns of functional connectivity within and between functional networks in children and adolescents with autism spectrum disorders, compared to typically developing peers. Resting-state functional magnetic resonance imaging data for 141 children and adolescents (7–17 years) selected from an in-house sample and four sites contributing to the Autism Brain Imaging Database Exchange (ABIDE I and II) were submitted to group independent component analysis to generate resting-state functional networks. Functional connectivity was estimated by generating resting-state functional network correlation matrices, which were directly compared between males and females, and autism spectrum disorder and typically developing groups. Results revealed greater connectivity within the default mode network in ty...
Autism spectrum disorders (ASDs) are increasingly prevalent neurodevelopmental disorders characte... more Autism spectrum disorders (ASDs) are increasingly prevalent neurodevelopmental disorders characterized by sociocommunicative impairments. Growing consensus indicates that neurobehavioral abnormalities require explanation in terms of interconnected networks. Despite theoretical speculations about increased local and reduced distal connectivity, links between local and distal functional connectivity have not been systematically investigated in ASDs. Specifically, it remains open whether hypothesized local overconnectivity may reflect isolated versus overly integrative processing. Resting state functional MRI data from 57 children and adolescents with ASDs and 51 typically developing (TD) participants were included. In regional homogeneity (ReHo) analyses, pericalcarine visual cortex was found be locally overconnected (ASD > TD). Using this region as seed in whole-brain analyses, we observed overconnectivity in distal regions, specifically middle frontal gyri, for an ASD subgroup id...
Social cognitive and affective neuroscience, Jan 21, 2017
The neural underpinnings of repetitive behaviors (RBs) in autism spectrum disorders (ASDs), rangi... more The neural underpinnings of repetitive behaviors (RBs) in autism spectrum disorders (ASDs), ranging from cognitive to motor characteristics, remain unknown. We assessed RB symptomatology in 50 ASD and 52 typically developing (TD) children and adolescents (ages 8-17 years), examining intrinsic functional connectivity (iFC) of corticostriatal circuitry, which is important for reward-based learning and integration of emotional, cognitive, and motor processing, and considered impaired in ASDs. Connectivity analyses were performed for three functionally distinct striatal seeds (limbic, frontoparietal, motor). Functional connectivity with cortical regions of interest was assessed for corticostriatal circuit connectivity indices and ratios, testing the balance of connectivity between circuits. Results showed corticostriatal overconnectivity of limbic and frontoparietal seeds, but underconnectivity of motor seeds. Correlations with RBs were found for connectivity between the striatal motor ...
The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the sco... more The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the scope of brain connectomics research in Autism Spectrum Disorder (ASD). Consistent with the initial ABIDE effort (ABIDE I), that released 1112 datasets in 2012, this new multisite open-data resource is an aggregate of resting state functional magnetic resonance imaging (MRI) and corresponding structural MRI and phenotypic datasets. ABIDE II includes datasets from an additional 487 individuals with ASD and 557 controls previously collected across 16 international institutions. The combination of ABIDE I and ABIDE II provides investigators with 2156 unique cross-sectional datasets allowing selection of samples for discovery and/or replication. This sample size can also facilitate the identification of neurobiological subgroups, as well as preliminary examinations of sex differences in ASD. Additionally, ABIDE II includes a range of psychiatric variables to inform our understanding of the neur...
Asymmetrical frontal electroencephalography (EEG) activity is associated with motivational neural... more Asymmetrical frontal electroencephalography (EEG) activity is associated with motivational neural systems of approach/withdrawal behaviors. Greater left frontal EEG has been linked to increased appetitive tendencies whereas increased right frontal activity is related to the activation of avoidance mechanisms. Williams syndrome (WS) is a genetic condition characterized by a highly sociable personality manifested by a propensity to approach strangers and decreased social fear. Consequently, the current study was designed to investigate the frontal cortical activity during resting state, indexed by relative alpha power, in adults with WS as compared to typically developing (TD) controls, and a subgroup of TD extraverts. Results indicated that participants with WS produced attenuated left frontal activity relative to TD peers, or TD extraverts in particular; yet, no groups differed in their degree of right frontal activity. Finally, while both TD group and the extravert subset showed tr...
Neuroimaging studies have revealed atypical activation during language and executive tasks in ind... more Neuroimaging studies have revealed atypical activation during language and executive tasks in individuals with autism spectrum disorders (ASD). However, the spatiotemporal stages of processing associated with these dysfunctions remain poorly understood. Using an anatomically constrained magnetoencephalography approach, we examined event-related theta oscillations during a double-duty lexical decision task that combined demands on lexico-semantic processing and executive functions. Relative to typically developing peers, high-functioning adolescents with ASD had lower performance accuracy on trials engaging selective semantic retrieval and cognitive control. They showed an early overall theta increase in the left fusiform cortex followed by greater activity in the left-lateralized temporal (starting at ~250 ms) and frontal cortical areas (after ~450 ms) known to contribute to language processing. During response preparation and execution, the ASD group exhibited elevated theta in the...
Although a growing literature highlights sex differences in autism spectrum disorder clinical pre... more Although a growing literature highlights sex differences in autism spectrum disorder clinical presentation, less is known about female variants at the neural level. We investigated sex-related patterns of functional connectivity within and between functional networks in children and adolescents with autism spectrum disorders, compared to typically developing peers. Resting-state functional magnetic resonance imaging data for 141 children and adolescents (7–17 years) selected from an in-house sample and four sites contributing to the Autism Brain Imaging Database Exchange (ABIDE I and II) were submitted to group independent component analysis to generate resting-state functional networks. Functional connectivity was estimated by generating resting-state functional network correlation matrices, which were directly compared between males and females, and autism spectrum disorder and typically developing groups. Results revealed greater connectivity within the default mode network in ty...
Autism spectrum disorders (ASDs) are increasingly prevalent neurodevelopmental disorders characte... more Autism spectrum disorders (ASDs) are increasingly prevalent neurodevelopmental disorders characterized by sociocommunicative impairments. Growing consensus indicates that neurobehavioral abnormalities require explanation in terms of interconnected networks. Despite theoretical speculations about increased local and reduced distal connectivity, links between local and distal functional connectivity have not been systematically investigated in ASDs. Specifically, it remains open whether hypothesized local overconnectivity may reflect isolated versus overly integrative processing. Resting state functional MRI data from 57 children and adolescents with ASDs and 51 typically developing (TD) participants were included. In regional homogeneity (ReHo) analyses, pericalcarine visual cortex was found be locally overconnected (ASD > TD). Using this region as seed in whole-brain analyses, we observed overconnectivity in distal regions, specifically middle frontal gyri, for an ASD subgroup id...
Social cognitive and affective neuroscience, Jan 21, 2017
The neural underpinnings of repetitive behaviors (RBs) in autism spectrum disorders (ASDs), rangi... more The neural underpinnings of repetitive behaviors (RBs) in autism spectrum disorders (ASDs), ranging from cognitive to motor characteristics, remain unknown. We assessed RB symptomatology in 50 ASD and 52 typically developing (TD) children and adolescents (ages 8-17 years), examining intrinsic functional connectivity (iFC) of corticostriatal circuitry, which is important for reward-based learning and integration of emotional, cognitive, and motor processing, and considered impaired in ASDs. Connectivity analyses were performed for three functionally distinct striatal seeds (limbic, frontoparietal, motor). Functional connectivity with cortical regions of interest was assessed for corticostriatal circuit connectivity indices and ratios, testing the balance of connectivity between circuits. Results showed corticostriatal overconnectivity of limbic and frontoparietal seeds, but underconnectivity of motor seeds. Correlations with RBs were found for connectivity between the striatal motor ...
The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the sco... more The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the scope of brain connectomics research in Autism Spectrum Disorder (ASD). Consistent with the initial ABIDE effort (ABIDE I), that released 1112 datasets in 2012, this new multisite open-data resource is an aggregate of resting state functional magnetic resonance imaging (MRI) and corresponding structural MRI and phenotypic datasets. ABIDE II includes datasets from an additional 487 individuals with ASD and 557 controls previously collected across 16 international institutions. The combination of ABIDE I and ABIDE II provides investigators with 2156 unique cross-sectional datasets allowing selection of samples for discovery and/or replication. This sample size can also facilitate the identification of neurobiological subgroups, as well as preliminary examinations of sex differences in ASD. Additionally, ABIDE II includes a range of psychiatric variables to inform our understanding of the neur...
Asymmetrical frontal electroencephalography (EEG) activity is associated with motivational neural... more Asymmetrical frontal electroencephalography (EEG) activity is associated with motivational neural systems of approach/withdrawal behaviors. Greater left frontal EEG has been linked to increased appetitive tendencies whereas increased right frontal activity is related to the activation of avoidance mechanisms. Williams syndrome (WS) is a genetic condition characterized by a highly sociable personality manifested by a propensity to approach strangers and decreased social fear. Consequently, the current study was designed to investigate the frontal cortical activity during resting state, indexed by relative alpha power, in adults with WS as compared to typically developing (TD) controls, and a subgroup of TD extraverts. Results indicated that participants with WS produced attenuated left frontal activity relative to TD peers, or TD extraverts in particular; yet, no groups differed in their degree of right frontal activity. Finally, while both TD group and the extravert subset showed tr...
Uploads