Papers by Jason Cooperrider
In this study, we attempted to determine whether larger NF effects occur for low-WF words than fo... more In this study, we attempted to determine whether larger NF effects occur for low-WF words than for high-WF words. The experiment employed a lexical-decision task, in which participants were presented with a lists of single items, half of which were words and half were pronounceable nonwords, varied along possible extreme values of high/low WF and NF for 4and 5-letter words. The primary theoretical implication of the study is that there is no search process involved in lexical access, rather that lexical access is a selection event based on the level of activation of a lexical entry produced by semantic, orthographic, and phonological information as it is processed pre-perceptually. Some practical implications of the study are a better understanding of dyslexia and ways to improve the reading habits of children. WF and NF Interactions in Lexical Access 3 Interactions between Word Frequency and Neighborhood Frequency in Lexical Access There are many different characteristics of words ...
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Background: A core deficit of Autism Spectrum Conditions (ASCs) is language impairment. While dat... more Background: A core deficit of Autism Spectrum Conditions (ASCs) is language impairment. While data exist about the brain basis for auditory language comprehension, little is known about whether differences exist in brain activation patterns during reading in ASC. Objectives: The objective of this study was to compare regional brain activity between individuals with an ASC and typically developing (TD) controls during a visual language task. Methods: Functional magnetic resonance imaging (fMRI) was performed on a 3-Tesla Siemens Trio MR scanner of individuals engaging in a visual language task. Participants in the study were 22 high-functioning ASC males (aged 12-42 years, mean age of 23 years, 1 left-handed) and 29 TD males (aged 8-39 years, mean age of 21 years, 1 left-handed). The visual language task consisted of alternating blocks of fixation on a crosshair and sentence reading, with each block lasting for 20 seconds, for a total task time of 4 minutes. The sentences in each sen...
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Background: Dr. Temple Grandin is the most renowned woman with autism in the world. She has gener... more Background: Dr. Temple Grandin is the most renowned woman with autism in the world. She has generously provided science with many insights into the mind of individuals with autism and has been an inspiration to many, given her enormous success in the face of many challenges. Because of the uniqueness of her mind and her exceptional abilities, it seems scientifically prudent to examine her brain to better understand how brain structure and function are related to outstanding ability and disability within the same brain. Objectives: The objective of this study is to begin to elucidate the neuroanatomical and functional basis of Dr. Grandin’s cognitive strengths and weaknesses. Methods: 3-Tesla anatomical, diffusion tensor, and functional MR imaging was performed on Dr. Grandin and compared to three female age-matched controls (Dr. Grandin age 61.3 years; controls mean age 62.3 years, range 59.1 to 67.9 years). MP-RAGE, T2-weighted anatomical, 12-direction DTI, and functional MRI (visu...
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Brain, 2011
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In this study, we attempted to determine whether larger NF effects occur for low-WF words than fo... more In this study, we attempted to determine whether larger NF effects occur for low-WF words than for high-WF words. The experiment employed a lexical-decision task, in which participants were presented with a lists of single items, half of which were words and half were pronounceable nonwords, varied along possible extreme values of high/low WF and NF for 4- and 5-letter words. The primary theoretical implication of the study is that there is no search process involved in lexical access, rather that lexical access is a selection event based on the level of activation of a lexical entry produced by semantic, orthographic, and phonological information as it is processed pre-perceptually. Some practical implications of the study are a better understanding of dyslexia and ways to improve the reading habits of children.
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The cortical underconnectivity theory asserts that reduced long-range functional connectivity mig... more The cortical underconnectivity theory asserts that reduced long-range functional connectivity might contribute to a neural mechanism for autism. We examined resting-state blood oxygen level-dependent interhemispheric correlation in 53 males with high-functioning autism and 39 typically developing males from late childhood through early adulthood. By constructing spatial maps of correlation between homologous voxels in each hemisphere, we found significantly reduced interhemispheric correlation specific to regions with functional relevance to autism: sensorimotor cortex, anterior insula, fusiform gyrus, superior temporal gyrus, and superior parietal lobule. Observed interhemispheric connectivity differences were better explained by diagnosis of autism than by potentially confounding neuropsychological metrics of language, IQ, or handedness. Although both corpus callosal volume and gray matter interhemispheric connectivity were significantly reduced in autism, no direct relationship was observed between them, suggesting that structural and functional metrics measure different aspects of interhemispheric connectivity. In the control but not the autism sample, there was decreasing interhemispheric correlation with subject age. Greater differences in interhemispheric correlation were seen for more lateral regions in the brain. These findings suggest that long-range connectivity abnormalities in autism are spatially heterogeneous and that transcallosal connectivity is decreased most in regions with functions associated with behavioral abnormalities in autism. Autism subjects continue to show developmental differences in interhemispheric connectivity into early adulthood.
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Group differences in resting state functional magnetic resonance imaging connectivity between ind... more Group differences in resting state functional magnetic resonance imaging connectivity between individuals with autism and typically developing controls have been widely replicated for a small number of discrete brain regions, yet the whole-brain distribution of connectivity abnormalities in autism is not well characterized. It is also unclear whether functional connectivity is sufficiently robust to be used as a diagnostic or prognostic metric in individual patients with autism. We obtained pairwise functional connectivity measurements from a lattice of 7266 regions of interest covering the entire grey matter (26.4 million connections) in a well-characterized set of 40 male adolescents and young adults with autism and 40 age-, sex- and IQ-matched typically developing subjects. A single resting state blood oxygen level-dependent scan of 8 min was used for the classification in each subject. A leave-one-out classifier successfully distinguished autism from control subjects with 83% sensitivity and 75% specificity for a total accuracy of 79% (P = 1.1 × 10(-7)). In subjects <20 years of age, the classifier performed at 89% accuracy (P = 5.4 × 10(-7)). In a replication dataset consisting of 21 individuals from six families with both affected and unaffected siblings, the classifier performed at 71% accuracy (91% accuracy for subjects <20 years of age). Classification scores in subjects with autism were significantly correlated with the Social Responsiveness Scale (P = 0.05), verbal IQ (P = 0.02) and the Autism Diagnostic Observation Schedule-Generic's combined social and communication subscores (P = 0.05). An analysis of informative connections demonstrated that region of interest pairs with strongest correlation values were most abnormal in autism. Negatively correlated region of interest pairs showed higher correlation in autism (less anticorrelation), possibly representing weaker inhibitory connections, particularly for long connections (Euclidean distance >10 cm). Brain regions showing greatest differences included regions of the default mode network, superior parietal lobule, fusiform gyrus and anterior insula. Overall, classification accuracy was better for younger subjects, with differences between autism and control subjects diminishing after 19 years of age. Classification scores of unaffected siblings of individuals with autism were more similar to those of the control subjects than to those of the subjects with autism. These findings indicate feasibility of a functional connectivity magnetic resonance imaging diagnostic assay for autism.
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Cognitive processing in autism has been characterized by a difficulty with the abstraction of inf... more Cognitive processing in autism has been characterized by a difficulty with the abstraction of information across multiple stimuli or situations and subsequent generalization to new stimuli or situations. This apparent difficulty leads to the suggestion that prototype formation, a process of creating a mental summary representation of multiple experienced stimuli that go together in a category, may be impaired in autism. Adults with high functioning autism and a typically developing comparison group matched on age and IQ completed a random dot pattern categorization task. Participants with autism demonstrated intact prototype formation in all four ways it was operationally defined, and this performance was not significantly different from that of control participants. However, participants with autism categorized dot patterns that were more highly distorted from the category prototypes less accurately than did control participants. These findings suggest, at least within the constraints of the random dot pattern task, that although prototype formation may not be impaired in autism, difficulties may exist with the generalization of what has been learned about a category to novel stimuli, particularly as they become less similar to the category's prototype.
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Autism is a complex neurological condition characterized by childhood onset of dysfunction in mul... more Autism is a complex neurological condition characterized by childhood onset of dysfunction in multiple cognitive domains including socio-emotional function, speech and language, and processing of internally versus externally directed stimuli. Although gross brain anatomic differences in autism are well established, recent studies investigating regional differences in brain structure and function have yielded divergent and seemingly contradictory results. How regional abnormalities relate to the autistic phenotype remains unclear. We hypothesized that autism exhibits distinct perturbations in network-level brain architecture, and that cognitive dysfunction may be reflected by abnormal network structure. Network-level anatomic abnormalities in autism have not been previously described. We used structural covariance MRI to investigate network-level differences in gray matter structure within two large-scale networks strongly implicated in autism, the salience network and the default mode network, in autistic subjects and age-, gender-, and IQ-matched controls. We report specific perturbations in brain network architecture in the salience and default-mode networks consistent with clinical manifestations of autism. Extent and distribution of the salience network, involved in social-emotional regulation of environmental stimuli, is restricted in autism. In contrast, posterior elements of the default mode network have increased spatial distribution, suggesting a 'posteriorization' of this network. These findings are consistent with a network-based model of autism, and suggest a unifying interpretation of previous work. Moreover, we provide evidence of specific abnormalities in brain network architecture underlying autism that are quantifiable using standard clinical MRI.
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Despite repeated findings of abnormal corpus callosum structure in autism, the developmental traj... more Despite repeated findings of abnormal corpus callosum structure in autism, the developmental trajectories of corpus callosum growth in the disorder have not yet been reported. In this study, we examined corpus callosum size from a developmental perspective across a 30-year age range in a large cross-sectional sample of individuals with autism compared to a typically developing sample. Midsagittal corpus callosum area and the 7 Witelson subregions were examined in 68 males with autism (mean age 14.1 years; range 3-36 years) and 47 males with typical development (mean age 15.3 years; range 4-29 years). Controlling for total brain volume, increased variability in total corpus callosum area was found in autism. In autism, increased midsagittal areas were associated with reduced severity of autism behaviors, higher intelligence, and faster speed of processing (p=0.003, p=0.011, p=0.013, respectively). A trend toward group differences in isthmus development was found (p=0.029, uncorrected). These results suggest that individuals with autism benefit functionally from increased corpus callosum area. Our cross-sectional examination also shows potential maturational abnormalities in autism, a finding that should be examined further with longitudinal datasets.
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It is unclear how standardized neuropsychological measures of motor function relate to brain volu... more It is unclear how standardized neuropsychological measures of motor function relate to brain volumes of motor regions in autism spectrum disorder (ASD). An all-male sample composed of 59 ASD and 30 controls (ages 5-33 years) completed three measures of motor function: strength of grip (SOG), finger tapping test (FTT), and grooved pegboard test (GPT). Likewise, all participants underwent magnetic resonance imaging with region of interest (ROI) volumes obtained to include the following regions: motor cortex (precentral gyrus), somatosensory cortex (postcentral gyrus), thalamus, basal ganglia, cerebellum, and caudal middle frontal gyrus. These traditional neuropsychological measures of motor function are assumed to differ in motor complexity, with GPT requiring the most followed by FTT and SOG. Performance by ASD participants on the GPT and FTT differed significantly from that of controls, with the largest effect size differences observed on the more complex GPT task. Differences on the SOG task between the two groups were nonsignificant. Since more complex motor tasks tap more complex networks, poorer GPT performance by those with ASD may reflect less efficient motor networks. There was no gross pathology observed in classic motor areas of the brain in ASD, as ROI volumes did not differ, but FTT was negatively related to motor cortex volume in ASD. The results suggest a hierarchical motor disruption in ASD, with difficulties evident only in more complex tasks as well as a potential anomalous size-function relation in motor cortex in ASD.
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Prior studies have shown that performance on standardized measures of memory in children with aut... more Prior studies have shown that performance on standardized measures of memory in children with autism spectrum disorder (ASD) is substantially reduced in comparison to matched typically developing controls (TDC). Given reported deficits in face processing in autism, the current study compared performance on an immediate and delayed facial memory task for individuals with ASD and TDC. In addition, we examined volumetric differences in classic facial memory regions of interest (ROI) between the two groups, including the fusiform, amygdala, and hippocampus. We then explored the relationship between ROI volume and facial memory performance. We found larger volumes in the autism group in the left amygdala and left hippocampus compared to TDC. In contrast, TDC had larger left fusiform gyrus volumes when compared with ASD. Interestingly, we also found significant negative correlations between delayed facial memory performance and volume of the left and right fusiform and the left hippocampus for the ASD group but not for TDC. The possibility of larger fusiform volume as a marker of abnormal connectivity and decreased facial memory is discussed.
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Imaging the Brain in Autism, 2013
This chapter summarizes the findings from spectroscopic brain imaging studies of autism that have... more This chapter summarizes the findings from spectroscopic brain imaging studies of autism that have occurred thus far, including magnetic resonance spectroscopy [MRS (terms displayed in bold can be found in the Glossary for this chapter)], magnetic resonance imaging spectroscopy (MRSI), and near-infrared spectroscopy (NIRS). The chapter begins with a table summarizing all the NIRS studies of autism and moves on to a summary of the MRS/MRSI findings in autism. First, MRS/MRSI findings of young children with an autism spectrum disorder (ASD) are summarized, followed by MRS/MRSI findings from specific brain regions and in different types of brain tissue (gray and white matter). The chapter then examines how various characteristics of study participants (age, sex, ASD subtypes, and clinical features) and other potentially confounding variables (cerebral volume, medication use, sedation during scanning, and methods for measuring metabolites) might lead to differences in MRS/MRSI findings. The chapter concludes by exploring what findings from MRS/MRSI studies suggest about possible neurodevelopmental mechanisms of autism. The chapter contains numerous tables to provide convenient summaries of spectroscopy studies of autism that have been published in the literature. The chapter also contains teaching boxes that provide information on the neurochemicals examined in MRS/MRSI studies of autism and some background on MRS/MRSI methods, in addition to a commentary provided by a leading MRS/MRSI expert, along with his biographical information. Overall, this chapter will provide those interested in autism neuroimaging with a comprehensive portrait of the spectroscopic neuroimaging that has been done in autism thus far, providing both a retrospective and a prospective look at this challenging and important area of research.
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Drafts by Jason Cooperrider
Background
A core deficit of Autism Spectrum Conditions (ASCs) is communication impairment. While... more Background
A core deficit of Autism Spectrum Conditions (ASCs) is communication impairment. While data exist about the brain basis for auditory language comprehension, little is known about whether differences exist in brain activation patterns during reading in ASC. The purpose of this study was to compare regional brain activity between individuals with an ASC and typically developing (TD) controls during a visual language task.
Findings
Functional magnetic resonance imaging (fMRI) was performed on 22 high-functioning ASC and 29 TD males. Participants were instructed to read each sentence presented during the visual language task and to think, not speak, the word they thought best completed each sentence. Similar patterns of activity were observed between the two groups during the task versus fixation/rest, with activation in brain regions typically associated with reading. Both groups were strongly left-lateralized in Broca's and Wernicke's areas, and lateral premotor cortex. No regions showed significantly higher activity for control than for ASC participants, but significantly increased activity was found in ASC relative to control participants in the left intraparietal sulcus (IPS).
Conclusions
Increased activation is observed in the IPS of ASC participants during a sentence-completion task, which could indicate that more attentional resources or concentration are required while reading. This increase might be a compensatory mechanism for the communication deficits commonly found in ASCs or might indicate a failure of ASC individuals to disengage attention to external stimuli while reading. Another possibility is that increased visual imagery occurs in individuals with an ASC during reading.
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Papers by Jason Cooperrider
Drafts by Jason Cooperrider
A core deficit of Autism Spectrum Conditions (ASCs) is communication impairment. While data exist about the brain basis for auditory language comprehension, little is known about whether differences exist in brain activation patterns during reading in ASC. The purpose of this study was to compare regional brain activity between individuals with an ASC and typically developing (TD) controls during a visual language task.
Findings
Functional magnetic resonance imaging (fMRI) was performed on 22 high-functioning ASC and 29 TD males. Participants were instructed to read each sentence presented during the visual language task and to think, not speak, the word they thought best completed each sentence. Similar patterns of activity were observed between the two groups during the task versus fixation/rest, with activation in brain regions typically associated with reading. Both groups were strongly left-lateralized in Broca's and Wernicke's areas, and lateral premotor cortex. No regions showed significantly higher activity for control than for ASC participants, but significantly increased activity was found in ASC relative to control participants in the left intraparietal sulcus (IPS).
Conclusions
Increased activation is observed in the IPS of ASC participants during a sentence-completion task, which could indicate that more attentional resources or concentration are required while reading. This increase might be a compensatory mechanism for the communication deficits commonly found in ASCs or might indicate a failure of ASC individuals to disengage attention to external stimuli while reading. Another possibility is that increased visual imagery occurs in individuals with an ASC during reading.
A core deficit of Autism Spectrum Conditions (ASCs) is communication impairment. While data exist about the brain basis for auditory language comprehension, little is known about whether differences exist in brain activation patterns during reading in ASC. The purpose of this study was to compare regional brain activity between individuals with an ASC and typically developing (TD) controls during a visual language task.
Findings
Functional magnetic resonance imaging (fMRI) was performed on 22 high-functioning ASC and 29 TD males. Participants were instructed to read each sentence presented during the visual language task and to think, not speak, the word they thought best completed each sentence. Similar patterns of activity were observed between the two groups during the task versus fixation/rest, with activation in brain regions typically associated with reading. Both groups were strongly left-lateralized in Broca's and Wernicke's areas, and lateral premotor cortex. No regions showed significantly higher activity for control than for ASC participants, but significantly increased activity was found in ASC relative to control participants in the left intraparietal sulcus (IPS).
Conclusions
Increased activation is observed in the IPS of ASC participants during a sentence-completion task, which could indicate that more attentional resources or concentration are required while reading. This increase might be a compensatory mechanism for the communication deficits commonly found in ASCs or might indicate a failure of ASC individuals to disengage attention to external stimuli while reading. Another possibility is that increased visual imagery occurs in individuals with an ASC during reading.