Neuroanatomical correlates of emotion-processing in children with unilateral brain lesion: A preliminary study of limbic system organization.

In this study, MRI and DTI were employed to examine subcortical volume and microstructural properties (FA, MD) of the limbic network, and their relationships with affect discrimination in 13 FL (6 right FL, M = 10.17 years; 7 left FL; M = 10.09) and 13 typically-developing children (TD; M = 10.16). Subcortical volume of the amygdala, hippocampus and thalamus and FA and MD of the fornix and anterior thalamic radiation (ATR) were examined. Results revealed no group differences across emotion-perception tasks or amygdalar volume. However, contrasting neuroanatomical patterns were observed in right versus left FL youth. Right FL participants showed increased left hippocampal and thalamic volume relative to left FL participants; whereas, the latter group showed increased right thalamic volume. DTI findings also indicated right FL children show greater MD of right fornix than other groups, whereas, left FL youth showed greater MD of left fornix. Right FL youth also showed lower FA of right fornix than left FL children, whereby the latter showed greater FA of left fornix and ATR. Differential associations between DTI indices and auditory/visual emotion-perception were observed across FL groups. Findings indicate diverging brain-behavioral relationships for emotion-perception among right and left FL children.

Anxiety and autonomic response to social-affective stimuli in individuals with Williams syndrome.

BACKGROUND: Williams syndrome (WS) is a genetic condition characterized by an unusual "hypersocial" personality juxtaposed by high anxiety. Recent evidence suggests that autonomic reactivity to affective face stimuli is disorganised in WS, which may contribute to emotion dysregulation and/or social disinhibition. METHODS: Electrodermal activity (EDA) and mean interbeat interval (IBI) of 25 participants with WS (19 - 57 years old) and 16 typically developing (TD; 17-43 years old) adults were measured during a passive presentation of affective face and voice stimuli. The Beck Anxiety Inventory was administered to examine associations between autonomic reactivity to social-affective stimuli and anxiety symptomatology. RESULTS: The WS group was characterized by higher overall anxiety symptomatology, and poorer anger recognition in social visual and aural stimuli relative to the TD group. No between-group differences emerged in autonomic response patterns. Notably, for participants with WS, increased anxiety was uniquely associated with diminished arousal to angry faces and voices. In contrast, for the TD group, no associations emerged between anxiety and physiological responsivity to social-emotional stimuli. CONCLUSIONS: The anxiety associated with WS appears to be intimately related to reduced autonomic arousal to angry social stimuli, which may also be linked to the characteristic social disinhibition.

Social functioning and autonomic nervous system sensitivity across vocal and musical emotion in Williams syndrome and autism spectrum disorder.

Both Williams syndrome (WS) and autism spectrum disorders (ASD) are associated with unusual auditory phenotypes with respect to processing vocal and musical stimuli, which may be shaped by the atypical social profiles that characterize the syndromes. Autonomic nervous system (ANS) reactivity to vocal and musical emotional stimuli was examined in 12 children with WS, 17 children with ASD, and 20 typically developing (TD) children, and related to their level of social functioning. The results of this small-scale study showed that after controlling for between-group differences in cognitive ability, all groups showed similar emotion identification performance across conditions. Additionally, in ASD, lower autonomic reactivity to human voice, and in TD, to musical emotion, was related to more normal social functioning. Compared to TD, both clinical groups showed increased arousal to vocalizations. A further result highlighted uniquely increased arousal to music in WS, contrasted with a decrease in arousal in ASD and TD. The ASD and WS groups exhibited arousal patterns suggestive of diminished habituation to the auditory stimuli. The results are discussed in the context of the clinical presentation of WS and ASD.

Perception of emotion in musical performance in adolescents with autism spectrum disorders.

Individuals with autism spectrum disorders (ASD) are impaired in understanding the emotional undertones of speech, many of which are communicated through prosody. Musical performance also employs a form of prosody to communicate emotion, and the goal of this study was to examine the ability of adolescents with ASD to understand musical emotion. We designed an experiment in which each musical stimulus served as its own control while we varied the emotional expressivity by manipulating timing and amplitude variation. We asked children and adolescents with ASD and matched controls as well as individuals with Williams syndrome (WS) to rate how emotional these excerpts sounded. Results show that children and adolescents with ASD are impaired relative to matched controls and individuals with WS at judging the difference in emotionality among the expressivity levels. Implications for theories of emotion in autism are discussed in light of these findings.

Cross-modal influences of affect across social and non-social domains in individuals with Williams syndrome.

The Williams syndrome (WS) cognitive profile is characterized by relative strengths in face processing, an attentional bias towards social stimuli, and an increased affinity and emotional reactivity to music. An audio-visual integration study examined the effects of auditory emotion on visual (social/non-social) affect identification in individuals with WS and typically developing (TD) and developmentally delayed (DD) controls. The social bias in WS was hypothesized to manifest as an increased ability to process social than non-social affect, and a reduced auditory influence in social contexts. The control groups were hypothesized to perform similarly across conditions. The results showed that while participants with WS exhibited indistinguishable performance to TD controls in identifying facial affect, DD controls performed significantly more poorly. The TD group outperformed the WS and DD groups in identifying non-social affect. The results suggest that emotionally evocative music facilitated the ability of participants with WS to process emotional facial expressions. These surprisingly strong facial-processing skills in individuals with WS may have been due to the effects of combining social and music stimuli and to a reduction in anxiety due to the music in particular. Several directions for future research are suggested.

Atypical hemispheric asymmetry in the perception of negative human vocalizations in individuals with Williams syndrome.

Williams syndrome is a neurological condition associated with high levels of auditory reactivity and emotional expression combined with impaired perception of prosody. Yet, little is currently known about the neural organization of affective auditory processing in individuals with this disorder. The current study examines auditory emotion processing in individuals with Williams syndrome. Hemispheric organization for positive and negative human non-linguistic sound processing was compared in participants with and without the disorder using a dichotic listening paradigm. While controls exhibited an expected right cerebral hemisphere advantage for processing negative sounds, those with Williams syndrome showed the opposite pattern. No differences between the groups emerged for the positive stimuli. The results suggest aberrant processing of negative auditory information in Williams syndrome.

Neural organization of linguistic short-term memory is sensory modality-dependent: evidence from signed and spoken language.

Despite decades of research, there is still disagreement regarding the nature of the information that is maintained in linguistic short-term memory (STM). Some authors argue for abstract phonological codes, whereas others argue for more general sensory traces. We assess these possibilities by investigating linguistic STM in two distinct sensory-motor modalities, spoken and signed language. Hearing bilingual participants (native in English and American Sign Language) performed equivalent STM tasks in both languages during functional magnetic resonance imaging. Distinct, sensory-specific activations were seen during the maintenance phase of the task for spoken versus signed language. These regions have been previously shown to respond to nonlinguistic sensory stimulation, suggesting that linguistic STM tasks recruit sensory-specific networks. However, maintenance-phase activations common to the two languages were also observed, implying some form of common process. We conclude that linguistic STM involves sensory-dependent neural networks, but suggest that sensory-independent neural networks may also exist.

Reduced parietal and visual cortical activation during global processing in Williams syndrome.

Several lines of investigation suggest that individuals with Williams syndrome (WS), a neurodevelopmental disorder of well-characterized genetic etiology, have selective impairments in integrating local image elements into global configurations. We compared global processing abilities in 10 clinically and genetically diagnosed participants with WS (eight females, two males; mean age 31y 10mo [SD 9y 7mo], range 15y 5mo-48y 4mo) with a typically developed (TD) age- and sex-matched comparison group (seven females, one male; mean age 35y 2mo [SD 10y 10mo], range 24y-54y 7mo) using functional magnetic resonance imaging (fMRI). Behavioral data showed participants with WS to be significantly less accurate (p<0.042) together with a non-significant trend to be slower than the TD comparison group while performing the global processing task. fMRI data showed participants with WS to possess reduced activation in the visual and parietal cortices. Participants with WS also showed relatively normal activation in the ventral occipitotemporal cortex, but elevated activation in several posterior thalamic nuclei. These preliminary results largely confirm previous research findings and neural models implicating neurodevelopmental abnormalities in extended subcortical and cortical visual systems in WS, most notably dorsal-stream pathways.

To modulate or not to modulate: differing results in uniquely shaped Williams syndrome brains.

Voxel based morphometry (VBM) studies of Williams syndrome (WS) have demonstrated remarkably consistent findings of reduced posterior parietal gray matter compared to typical controls. Other WS VBM findings have been inconsistent, however. In particular, different findings have been reported for hypothalamus and orbitofrontal gray matter regions. We examined a sample of 8 WS and 9 control adults and show that the hypothalamus and orbitofrontal cortex results depend on whether the images undergo Jacobian modulation. Deformation based morphometry (DBM) analysis demonstrated that major brain shape differences between the groups accounted for the Jacobian modulated gray matter findings. These results indicate that cautious interpretations of modulated gray matter findings are warranted when there are gross shape and size differences between experimental groups. This study demonstrates the importance of methodological choices towards understanding a disorder like WS, but also highlights the consistency of parietal lobe, orbitofrontal, and midbrain findings for this disorder across methodologies, participants, and research groups.