Pubmed du 14/08/09

Pubmed du jour

2009-08-14 12:03:50

1. Allen R, Hill E, Heaton P. {{The subjective experience of music in autism spectrum disorder}}. {Ann N Y Acad Sci};2009 (Jul);1169:326-331.

Semi-structured interviews were conducted with 12 high-functioning adults on the autism spectrum in order to examine the nature of their personal experiences of music. The analysis showed that most participants exploit music for a wide range of purposes in the cognitive, emotional and social domains, but the autism spectrum disorder (ASD) group’s descriptions of mood states reflected a greater reliance on internally focused (arousal) rather than externally focused (emotive) language, when compared with studies of typically developing individuals.

2. Boso M, Comelli M, Vecchi T, Barale F, Politi P. {{Exploring musical taste in severely autistic subjects: preliminary data}}. {Ann N Y Acad Sci};2009 (Jul);1169:332-335.

As a consequence of frequent limbic alterations, autistic persons could judge pleasant and unpleasant music in an unusual manner. We explored this possibility by using consonant and dissonant music (test 2) and excluded the eventuality that they could prefer other auditory stimuli by comparing familiar music to environmental sounds (test 1). In both tests, severe autistics and controls were asked to listen under two conditions (familiar music versus environmental sounds; pleasant versus unpleasant music) in a counterbalanced order while the time spent during each condition was measured. Both groups significantly preferred the musical task and the pleasant music condition. No difference between groups was detected. Results demonstrate that severely autistic subjects share with healthy people the same musical preferences.

3. Heaton P, Allen R. {{« With concord of sweet sounds… »: new perspectives on the diversity of musical experience in autism and other neurodevelopmental conditions}}. {Ann N Y Acad Sci};2009 (Jul);1169:318-325.

Questions about music’s evolution and functions have long excited interest among scholars. More recent theoretical accounts have stressed the importance of music’s social origins and functions. Autism and Williams syndrome, neurodevelopmental disorders supposedly characterized by contrasting social and musical phenotypes, have been invoked as evidence for these. However, empirical data on social skills and deficits in autism and Williams syndrome do not support the notion of contrasting social phenotypes: research findings suggest that the social deficits characteristic of both disorders may increase rather than reduce the importance of music. Current data do not allow for a direct comparison of musical phenotypes in autism and Williams syndrome, although it is noted that deficits in music cognition have been observed in Williams syndrome, but not in autism. In considering broader questions about musical understanding in neurodevelopmental disorders, we conclude that intellectual impairment is likely to result in qualitative differences between handicapped and typical listeners, but this does not appear to limit the extent to which individuals can derive benefits from the experience of listening to music.

4. Ladas T, Chan SA, Ogier M, Smith C, Katz DM. {{Enhanced dense core granule function and adrenal hypersecretion in a mouse model of Rett syndrome}}. {Eur J Neurosci};2009 (Aug 7)

Abstract Rett syndrome (RTT) is a progressive developmental disorder resulting from loss-of-function mutations in the gene encoding methyl-CpG-binding protein 2 (MeCP2), a transcription regulatory protein. The RTT phenotype is complex and includes severe cardiorespiratory abnormalities, dysautonomia and behavioral symptoms of elevated stress. These findings have been attributed to an apparent hyperactivity of the sympathetic nervous system due to defects in brainstem development; however, the possibility that the peripheral sympathoadrenal axis itself is abnormal has not been explored. The present study demonstrates that the adrenal medulla and sympathetic ganglia of Mecp2 null mice exhibit markedly reduced catecholamine content compared with wild-type controls. Despite this, null animals exhibit significantly higher plasma epinephrine levels, suggesting enhanced secretory granule function in adrenal chromaffin cells. Indeed, we find that Mecp2 null chromaffin cells exhibit a cell autonomous hypersecretory phenotype characterized by significant increases in the speed and size of individual secretory granule fusion events in response to electrical stimulation. These findings appear to indicate accelerated formation and enhanced dilation of the secretory granule fusion pore, resulting in elevated catecholamine release. Our data therefore highlight abnormal catecholamine function in the sympathoadrenal axis as a potential source of autonomic dysfunction in RTT. These findings may help to explain the apparent ‘overactivity’ of the sympathetic nervous system reported in patients with RTT.

5. New JJ, Schultz RT, Wolf J, Niehaus JL, Klin A, German TC, Scholl BJ. {{The scope of social attention deficits in autism: Prioritized orienting to people and animals in static natural scenes}}. {Neuropsychologia};2009 (Aug 14)

A central feature of autism spectrum disorder (ASD) is an impairment in ‘social attention’ – the prioritized processing of socially-relevant information, e.g. the eyes and face. Socially relevant stimuli are also preferentially attended in a broader categorical sense, however: observers orient preferentially to people and animals (compared to inanimate objects) in complex natural scenes. To measure the scope of social attention deficits in autism, observers viewed alternating versions of a natural scene on each trial, and had to ‘spot the difference’ between them – where the difference involved either an animate or inanimate object. Change detection performance was measured as an index of attentional prioritization. Individuals with ASD showed the same prioritized social attention for animate categories as did control participants. This could not be explained by lower-level visual factors, since the effects disappeared when using blurred or inverted images. These results suggest that social attention – and its impairment in autism – may not be a unitary phenomenon: impairments in visual processing of specific social cues may occur despite intact categorical prioritization of social agents.

6. Schnetz-Boutaud NC, Anderson BM, Brown KD, Wright HH, Abramson RK, Cuccaro ML, Gilbert JR, Pericak-Vance MA, Haines JL. {{Examination of tetrahydrobiopterin pathway genes in autism}}. {Genes Brain Behav};2009 (Jul 14)

Autism is a complex disorder with a high degree of heritability and significant phenotypic and genotypic heterogeneity. Although candidate gene studies and genome-wide screens have failed to identify major causal loci associated with autism, numerous studies have proposed association with several variations in genes in the dopaminergic and serotonergic pathways. Because tetrahydrobiopterin (BH4) is the essential cofactor in the synthesis of these two neurotransmitters, we genotyped 25 SNPs in nine genes of the BH4 pathway in a total of 403 families. Significant nominal association was detected in the gene for 6-pyruvoyl-tetrahydropterin synthase, PTS (chromosome 11), with P = 0.009; this result was not restricted to an affected male-only subset. Multilocus interaction was detected in the BH4 pathway alone, but not across the serotonin, dopamine and BH4 pathways.

7. Senju A, Southgate V, White S, Frith U. {{Mindblind eyes: an absence of spontaneous theory of mind in Asperger syndrome}}. {Science};2009 (Aug 14);325(5942):883-885.

Adults with Asperger syndrome can understand mental states such as desires and beliefs (mentalizing) when explicitly prompted to do so, despite having impairments in social communication. We directly tested the hypothesis that such individuals nevertheless fail to mentalize spontaneously. To this end, we used an eye-tracking task that has revealed the spontaneous ability to mentalize in typically developing infants. We showed that, like infants, neurotypical adults’ (n = 17 participants) eye movements anticipated an actor’s behavior on the basis of her false belief. This was not the case for individuals with Asperger syndrome (n = 19). Thus, these individuals do not attribute mental states spontaneously, but they may be able to do so in explicit tasks through compensatory learning.

8. Wu SH, Camarena V. {{MeCP2 function in the basolateral amygdala in Rett syndrome}}.{ J Neurosci};2009 (Aug 12);29(32):9941-9942.