These results provide strong evidence that adults with PDS have anomalous anatomy in perisylvian speech and language areas. No one anatomic feature distinguished the groups, but multiple loci within a widely distributed neural network differed between groups. These results provide the first evidence that anatomic anomalies within perisylvian speech-language areas may put an individual at risk for the development of stuttering.
In adults with persistent developmental stuttering and atypical PT anatomy, fluency is improved with DAF. These experimental subjects who showed improvement had more severe stuttering at baseline. Anomalous PT anatomy may be a neural risk for developmental stuttering in some individuals. Although a number of explanations are tenable, it may be that atypical rightward PT asymmetry may alter speech feedback, and treatment with DAF might allow these people to compensate.
Developmental stuttering is associated with atypical prefrontal and occipital lobe asymmetries. In addition, deficits in language processing were associated with some anatomic measures in the adults who stutter.
Individuals with Autism Spectrum Disorder (ASD) appear to show a general face discrimination deficit across a range of tasks including social–emotional judgments as well as identification and discrimination. However, functional magnetic resonance imaging (fMRI) studies probing the neural bases of these behavioral differences have produced conflicting results: while some studies have reported reduced or no activity to faces in ASD in the Fusiform Face Area (FFA), a key region in human face processing, others have suggested more typical activation levels, possibly reflecting limitations of conventional fMRI techniques to characterize neuron-level processing. Here, we test the hypotheses that face discrimination abilities are highly heterogeneous in ASD and are mediated by FFA neurons, with differences in face discrimination abilities being quantitatively linked to variations in the estimated selectivity of face neurons in the FFA. Behavioral results revealed a wide distribution of face discrimination performance in ASD, ranging from typical performance to chance level performance. Despite this heterogeneity in perceptual abilities, individual face discrimination performance was well predicted by neural selectivity to faces in the FFA, estimated via both a novel analysis of local voxel-wise correlations, and the more commonly used fMRI rapid adaptation technique. Thus, face processing in ASD appears to rely on the FFA as in typical individuals, differing quantitatively but not qualitatively. These results for the first time mechanistically link variations in the ASD phenotype to specific differences in the typical face processing circuit, identifying promising targets for interventions.
Perisylvian regions important for auditory processing include Heschl's gyrus (HG), the planum temporale (PT), the posterior superior temporal gyrus (pSTG), and the posterior ascending ramus (PAR). Sex-linked differences in language functions and anatomy have been suggested. To examine sex-linked differences, the authors used MRI to measure HG, PT, pSTG, and PAR volumes. Sex differences were found in right HG and right pSTG volumes but not in the left volumes of these structures. For the PT, there were sex differences in asymmetry; women exhibited leftward asymmetry of the PT, whereas men did not exhibit PT asymmetry. These findings suggest that there are sex-linked differences in the anatomy of primary and association auditory cortices.
Background
Individuals with autism spectrum disorders (ASD) often struggle with complex tasks, such as those requiring divided attention (simultaneously completing two independent tasks) which also place high demands on working memory. Prior research shows that divided attention is impaired in adults and children with ASD, and is related to ASD and co-morbid attention deficit/hyperactivity disorder ADHD symptoms, but the impact on everyday functioning is unclear. Because ADHD symptoms are associated with poor divided attention and working memory performance in children with ASD, we also examined ADHD symptoms as moderators of divided attention performance.
Method
We examined performance on the Consonant Trigrams Test (CTT) between high-functioning 8–13-year-olds with ASD (n=28) and typically developing controls (n=18) matched on age and IQ. In the ASD group, we also correlated performance with ADHD symptoms and behavior ratings of everyday working memory.
Results
CTT performance in children with ASD was significantly worse than in matched controls. A significant correlation between CTT performance and everyday working memory was observed, but CTT performance was not related to co-morbid ADHD symptoms, in the ASD group.
Conclusion
Divided attention with high working memory demands is a relative weakness in children with high-functioning ASD, this weakness relates to everyday functioning, and it is independent from ADHD symptoms. That ADHD symptoms are not associated with divided attention performance is inconsistent with one prior investigation, which likely results from using different divided attention tasks in the two studies.
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