Denoising the speaking brain: toward a robust technique for correcting artifact-contaminated fMRI data under severe motion.

A comprehensive set of methods based on spatial independent component analysis (sICA) is presented as a robust technique for artifact removal, applicable to a broad range of functional magnetic resonance imaging (fMRI) experiments that have been plagued by motion-related artifacts. Although the applications of sICA for fMRI denoising have been studied previously, three fundamental elements of this approach have not been established as follows: 1) a mechanistically-based ground truth for component classification; 2) a general framework for evaluating the performance and generalizability of automated classifiers; and 3) a reliable method for validating the effectiveness of denoising. Here we perform a thorough investigation of these issues and demonstrate the power of our technique by resolving the problem of severe imaging artifacts associated with continuous overt speech production. As a key methodological feature, a dual-mask sICA method is proposed to isolate a variety of imaging artifacts by directly revealing their extracerebral spatial origins. It also plays an important role for understanding the mechanistic properties of noise components in conjunction with temporal measures of physical or physiological motion. The potentials of a spatially-based machine learning classifier and the general criteria for feature selection have both been examined, in order to maximize the performance and generalizability of automated component classification. The effectiveness of denoising is quantitatively validated by comparing the activation maps of fMRI with those of positron emission tomography acquired under the same task conditions. The general applicability of this technique is further demonstrated by the successful reduction of distance-dependent effect of head motion on resting-state functional connectivity.

The neural correlates of non-spatial working memory in velocardiofacial syndrome (22q11.2 deletion syndrome).

Velocardiofacial syndrome (VCFS), also known as 22q11.2 deletion syndrome, is a neurogenetic disorder that is associated with both learning disabilities and a consistent neuropsychological phenotype, including deficits in executive function, visuospatial perception, and working memory. Anatomic imaging studies have identified significant volumetric reductions in the parietal lobe of individuals with VCFS, but several studies have reported that the frontal lobe is relatively preserved. We used functional magnetic resonance imaging to investigate the neural correlates of non-spatial working memory in 17 youths with VCFS, 10 of their unaffected siblings, and 10 community controls (with the same proportion of learning disabilities as the VCFS youths). Task performance of siblings tended to be more accurate than children with VCFS, who did not differ from community controls. All three-study groups recruited parietal regions that were equivalent in location and magnitude. Whereas the sibling group also recruited the dorsolateral prefrontal cortex (DLPFC), Broca's area, and anterior cingulate, DLPFC activation was absent in the whole brain analyses of children with VCFS and controls. Moreover, the magnitude of frontal activation in VCFS participants was restricted relative to both siblings and controls. These findings suggest that VCFS participants exhibit frontal hypoactivation that is not attributable to performance. In addition, VCFS children and controls (many with idiopathic learning disabilities) appear to rely on phonological rehearsal to hold information on line instead of the DLPFC. Despite previous anatomic MRI reports of preserved frontal lobe volumes in VCFS therefore, these fMRI findings suggest that the frontal component of the distributed network subserving executive function and working memory may be disrupted in youth with this disorder.

Autistic spectrum disorders in velo-cardio facial syndrome (22q11.2 deletion).

The extent to which the phenotype of children comorbid for velocardiofacial syndrome (VCFS) and autism spectrum disorders (ASD) differs from that of VCFS-only has not been studied. The sample consisted of 41 children (20 females) with VCFS, ranging in age from 6.5 years to 15.8 years. Eight children with VCFS met formal DSM-IV diagnostic criteria for autism based upon the ADI-R. These eight plus an additional nine participants met diagnostic criteria for an autistic spectrum disorder (VCFS + ASD). Ninety-four percent of the children with VCFS + ASD had a co-occurring psychiatric disorder while 60% of children with VCFS had a psychiatric disorder. Children with VCFS + ASD had larger right amygdala volumes. All other neuroanatomic regions of interest were statistically similar between the two groups.

Manic symptoms and behavioral dysregulation in youth with velocardiofacial syndrome (22q11.2 deletion syndrome).

Mania and bipolar disorder have been reported in adolescents and adults with velocardiofacial syndrome (VCFS; also known as 22q11.2 deletion syndrome). Children with VCFS have a high prevalence of attention-deficit/hyperactivity disorder (ADHD), which may constitute a risk factor for the eventual development of bipolar disorder in this population. Therefore, we sought to determine whether children with VCFS exhibit more manic symptoms than community controls that also may have learning disorders and ADHD. The study population consisted of 86 children with VCFS and 36 community controls from ages 9 to 15 years, using measures of Young Mania Rating Scale-Parent Version, Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL), Child Behavior Checklist (CBCL), and Wechsler Intelligence Scale for Children-3rd edition (WISC-III). The results indicate that manic symptoms were not more prevalent in VCFS than in a community sample of children with learning disorders and ADHD. However, after accounting for symptoms of depression and ADHD, we found that manic symptoms in VCFS predicted uniquely to scores on four Child Behavior Checklist (CBCL) subscales, including anxiety, somatization, thought, and conduct problems. In contrast, manic symptoms in controls predicted uniquely to conduct problems only. Accordingly, our findings of severe behavioral impairment in youth with VCFS and manic symptoms suggest that these children may warrant more intensive monitoring and treatment relative to youth with VCFS and ADHD only.

22q11.2DS deletion syndrome: developmental milestones in infants and toddlers.

BACKGROUND: The majority of children with 22q11.2DS deletion syndrome (22q11.2DS) have learning disabilities, and a substantial number have mental retardation. Although cognitive data have been reported on several samples of children with 22q11.2DS, data on their early developmental milestones are limited. METHODS: The present study used a retrospective design and asked parents to recall developmental milestones. The participants were 88 children with 22q11.2DS, 47 community controls, and 29 sibling controls. RESULTS: Although very early gross motor and expressive language milestones did not differ significantly from comparison groups, subsequent gross motor and expressive language milestones did, suggesting that children with 22q11.2DS may begin to lag behind their peers sometime after the first year of life in these two domains. These patterns were also apparent when a subset of intellectually comparable children (22q11.2DS, n = 40 vs community controls, n = 24) was analyzed. We further found that receptive language and social adaptive milestones did not differ from comparison samples in either the early or later period. Receptive language delays were predictive of later Wechsler Intelligence Scale for Children-Third Edition Perceptual Organization Index scores, particularly in girls with 22q11.2DS. CONCLUSIONS: This suggests that although receptive language may be an area of relative strength in the developmental profile of young children with 22q11.2DS, even mild receptive delays should not be overlooked in early interventions with children with this disorder.

Temporal lobe anatomy and psychiatric symptoms in velocardiofacial syndrome (22q11.2 deletion syndrome).

OBJECTIVE: To investigate the association between mesial temporal lobe morphology, ratios of prefrontal cortex to amygdala and hippocampus volumes, and psychiatric symptomatology in children and adolescents with velocardiofacial syndrome (VCFS). METHOD: Scores on behavioral rating scales and volumetric measures of the amygdala, hippocampus, and prefrontal cortex based on high-resolution magnetic resonance imaging were compared among 47 children with VCFS, 15 of their siblings, and 18 community controls. RESULTS: After covarying for whole brain volume, children with VCFS exhibited 11% greater volume of the left amygdala (p =.002) and 8% greater volume of the right amygdala (p =.01). Children with VCFS exhibited smaller volumes of the hippocampus, but not disproportionately to reductions in whole brain volume. Children with VCFS exhibited smaller volumetric ratios of prefrontal and orbitofrontal cortex to amygdala, but not prefrontal cortex to hippocampus. For children with VCFS, but not for the comparison sample, larger volumes of the amygdala and smaller ratios of prefrontal cortex to amygdala were associated with higher scores on the Internalizing, Externalizing, Anxiety, and Aggression scales of the Child Behavior Checklist and on the parent version of the Young Mania Rating Scale. CONCLUSIONS: These findings suggest that the prefrontal cortex-amygdala circuit that underlies emotional processing is disrupted in children with VCFS and may be an important neurobiological substrate of psychiatric disorder in these children.

Sex differences in cognitive functioning in velocardiofacial syndrome (VCFS).

Sex differences in cognitive functioning were investigated in children with velocardiofacial syndrome (VCFS), a genetic defect caused by a microdeletion on chromosome 22q.11. The study population consisted of six groups: 50 boys with VCFS (M = 11.1, SD = 2.7), 40 girls with VCFS (M = 10.8, SD = 2.5), 13 male siblings of the participant with VCFS (M = 12.3, SD = 1.9), 17 female siblings of the participant with VCFS (M = 12.2, SD = 1.9), and a race- and gender-ratio-matched sample of 28 boy community control participants (M = 10.7, SD =2.4) and 19 girl community control participants (M = 9.2, SD =2.3). Each participant received a psychological assessment including intellectual and academic achievement as well as structural magnetic resonance imaging of his or her brain. Our results indicate that boys with VCFS may be more cognitively affected than girls. In addition, and although cross-sectional in nature, our results document a negative association between age and cognitive functioning in girls with VCFS but not in boys. Sex differences in frontal lobe volume are generally seen in the general population between boys and girls (boys > girls) and across all three samples, this trend emerged. Relative to boys with VCFS, girls with VCFS may be less cognitively affected, although age is negatively associated with cognitive functioning in girls with VCFS but not boys, suggesting that girls with VCFS may fail to maintain this cognitive advantage over boys.

Gender-moderated dorsolateral prefrontal reductions in 22q11.2 Deletion Syndrome: implications for risk for schizophrenia.

To investigate the impact of the microdeletion on morphology of the prefrontal cortex in 22q11.2 Deletion Syndrome (22q11.2 DS), high-resolution, anatomic magnetic resonance imaging was performed on 19 children and adolescents with 22q11.2 DS (11 females, 8 males) and 18 unaffected controls (10 females, 8 males). Tissue volumes of the dorsolateral, dorsomedial, orbitolateral, and orbitomedial prefrontal cortex were measured. Tasks of executive function and working memory were administered to investigate the association between anatomy and function. Whole brain volume and frontal lobe tissue volume were preserved in girls but reduced in boys with 22q11.2 DS relative to age-matched controls. Dorsolateral prefrontal cortex (DLPFC) volumes were reduced in participants with 22q11.2 DS, although the gender-by-diagnosis effect found for frontal lobe was not as robust for DLPFC. DLPFC volumes were associated with performance on tasks of planning and emotional facial recognition. Longitudinal studies are needed to clarify whether gender differences in frontal lobe and DLPFC persist with development, and whether the volumes of the DLPFC are associated with eventual deterioration in adaptive/psychosocial function that may presage the onset of schizophrenia, for which individuals with 22q11.2 DS are at a disproportionately high risk.

Neural correlates and network connectivity underlying narrative production and comprehension: a combined fMRI and PET study.

The neural correlates of narrative production and comprehension remain poorly understood. Here, using positron emission tomography (PET), functional magnetic resonance imaging (fMRI), contrast and functional network connectivity analyses we comprehensively characterize the neural mechanisms underlying these complex behaviors. Eighteen healthy subjects told and listened to fictional stories during scanning. In addition to traditional language areas (e.g., left inferior frontal and posterior middle temporal gyri), both narrative production and comprehension engaged regions associated with mentalizing and situation model construction (e.g., dorsomedial prefrontal cortex, precuneus and inferior parietal lobules) as well as neocortical premotor areas, such as the pre-supplementary motor area and left dorsal premotor cortex. Narrative comprehension alone showed marked bilaterality, activating right hemisphere homologs of perisylvian language areas. Narrative production remained predominantly left lateralized, uniquely activating executive and motor-related regions essential to language formulation and articulation. Connectivity analyses revealed strong associations between language areas and the superior and middle temporal gyri during both tasks. However, only during storytelling were these same language-related regions connected to cortical and subcortical motor regions. In contrast, during story comprehension alone, they were strongly linked to regions supporting mentalizing. Thus, when employed in a more complex, ecologically-valid context, language production and comprehension show both overlapping and idiosyncratic patterns of activation and functional connectivity. Importantly, in each case the language system is integrated with regions that support other cognitive and sensorimotor domains.

Associations between performance on the Rey-Osterrieth Complex Figure and regional brain volumes in children with and without velocardiofacial syndrome.

Ninety-two children with velocardiofacial syndrome (VCFS), a genetic disorder caused by a microdeletion of chromosome 22q11.2 and an age, race, and gender-ratio comparable sample of 59 control participants were included in the project. Participants received an MRI as well as a comprehensive neuropsychological battery; the primary outcome measure in the current report is the Rey-Osterrieth Complex Figure (ROCF). Children with VCFS performed less well on the ROCF and have lower whole brain volume compared to controls. After controlling for whole brain volume differences, children with VCFS have bilaterally less parietal lobe gray and white matter yet more frontal lobe white matter. Brain-behavior relationships include: (a) for both groups, parietal volumes (both gray and white matter) predicted ROCF Copy Organization performance and frontal volumes (both gray and white matter) predicted ROCF Copy Accuracy performance; (b) for controls, frontal white matter also predicted ROCF Copy Organization performance; (c) ROCF Recall Organization performance was best predicted by frontal gray matter volume only in our controls; ROCF Recall Accuracy performance was best predicted by frontal gray matter volume in both groups; and (d) in children with VCFS, performance on the ROCF-Copy Structural Elements Accuracy scale was predicted by right hemisphere white matter volume. Our hypotheses were also retested using IQ-matched and whole brain volume-matched subsamples. Identical results were obtained in these analyses. Assumptions about the organization of and the localization of the brain structures that subserve specific cognitive functions in the typically developing brain may not apply in the abnormally developing brain.

A gender-moderated effect of a functional COMT polymorphism on prefrontal brain morphology and function in velo-cardio-facial syndrome (22q11.2 deletion syndrome).

Caused by a microdeletion at the q11.2 locus of chromosome 22, velo-cardio-facial syndrome (also known as VCFS, 22q11 deletion syndrome, DiGeorge sequence, and conotruncal anomalies face syndrome) is associated with a distinctive physical, neurocognitive, and psychiatric phenotype. Increasing interest has centered on identifying the candidate genes within the deleted region that may contribute to this phenotype. One attractive candidate gene is catechol-O-methyltransferase (COMT) because it encodes for a protein that degrades dopamine. Variability in COMT activity is related to a Val158Met polymorphism that has been implicated in prefrontal lobe cognitive and neuropsychiatric function. We examined the effect of this polymorphism on prefrontal anatomy and frontally-mediated neuropsychological function in 58 children with VCFS, 26 who were hemizygous for the Met allele and 32 for the Val allele. We found an allele by gender interaction effect on the volumes of the dorsal prefrontal and orbital prefrontal cortices. We did not find significant allele or gender by allele effects on neuropsychological tasks, although girls with the Met allele tended to perform better on the Wisconsin card sorting task. These data suggest that this functional COMT polymorphism may play a gender-moderated role in determining the neuroanatomic phenotype of individuals with VCFS. Longitudinal evaluation of these children is essential in order to identify potential clinical implications of this allele by gender interaction.