Absence of stimulus-driven synchronization effects on sensory perception in autism: Evidence for local underconnectivity?

<p>Abstract</p> <p>Background</p> <p>A number of neurophysiological characteristics demonstrated in autism share the common theme of under-connectivity in the cerebral cortex. One of the prominent theories of the cause of the dysfunctional connectivity in autism is based on distinct anatomical structures that differ between the autistic and the neurotypical cortex. The functional minicolumn has been identified as occupying a much smaller space in the cortex of people with autism as compared to neurotypical controls, and this aberration in architecture has been proposed to lead to under-connectivity at the local or within-macrocolumn level, which in turn leads to dysfunctional connectivity globally across cortical areas in persons with autism. Numerous reports have indicated reduced synchronization of activity on a large scale in the brains of people with autism. We hypothesized that if the larger-scale aberrant dynamics in autism were due – at least in part – to a widespread propagation of the errors introduced at the level of local connectivity between minicolumns, then aberrations in local functional connectivity should also be detectable in autism.</p> <p>Methods</p> <p>Recently, we reported a method for measuring the perceptual changes that are impacted by the presence of synchronized conditioning stimuli on the skin. In this study, the temporal order judgment (TOJ) and temporal discriminative threshold (TDT) of 10 adult autism subjects were assessed both in the absence and presence of synchronized conditioning vibrotactile stimuli.</p> <p>Results</p> <p>Our previous report demonstrated that delivering simultaneous and synchronized vibrotactile stimuli to near-adjacent skin sites decreases a subject's ability to determine temporal order by 3 to 4-fold. However, results presented in this report show that subjects with autism do not demonstrate such decreased capacity in temporal order judgment (TOJ) in the presence of synchronized conditioning stimuli, although these same subjects do have TOJ thresholds well above that of controls.</p> <p>Conclusion</p> <p>It is speculated that the differences in sensory perceptual capacities in the presence of synchronized conditioning stimuli in autism are due to local under-connectivity in cortex at the minicolumnar organizational level, and that the above-average TOJ thresholds in autism could be attributed to structural differences that have been observed in the frontostrial system of this population.</p

Perfluorodecalin-supported system enhances taxane production in hairy root cultures of Taxus x media var. Hicksii carrying a taxadiene synthase transgene

Enhanced taxane production was observed in a hybrid, two liquid phases containing, cultures of Taxus x media var. Hicksii hairy root carrying a taxadiene synthase transgene, supported with liquid perfluorodecalin (PFD) in degassed or aerated form. The hairy root cultures were elicited with methyl jasmonate (MJ, 100 μM) or coronatine (COR, 1 μM), and fed with sucrose and l-phenylalanine. The root growth was not stimulated by PFD addition, irrespective of the day of its application (day 0 and 14). However, in the cultures elicited with MJ and performed in the presence of PFD the final root biomass accumulation was higher than in cultures performed without PFD while the opposite effect was observed in cultures supplemented with COR. The highest paclitaxel content in root biomass was determined at the end of the cultures elicited with MJ and supplemented with PFD-degassed at day 0 or 14, 1,440.8 and 1,432.5 μg g−1 DW, respectively. The highest total (i.e. intracellular + extracellular: both in aqueous and PFD phases) paclitaxel yield in flasks (149.15 μg flask−1) was noted after the application of PFD-degassed at day 14. The other taxane detected was baccatin III, only in the root biomass, with the highest content (76.9 μg g−1 DW) observed under COR treatment. Although COR stimulated paclitaxel production with less efficiency than MJ, it resulted in higher paclitaxel excretion to the liquid phases of culture medium and PFD

Bonding in MgSi and AlMgSi Compounds Relevant to AlMgSi Alloys

The bonding and stability of MgSi and AlMgSi compounds relevant to AlMgSi alloys is investigated with the use of (L)APW+(lo) DFT calculations. We show that the $\beta$ and $\beta''$ phases found in the precipitation sequence are characterised by the presence of covalent bonds between Si-Si nearest neighbour pairs and covalent/ionic bonds between Mg-Si nearest neighbour pairs. We then investigate the stability of two recently discovered precipitate phases, U1 and U2, both containing Al in addition to Mg and Si. We show that both phases are characterised by tightly bound Al-Si networks, made possible by a transfer of charge from the Mg atoms.Comment: 11 pages, 30 figures, submitted to Phys. Rev.

Activity Participation Among Children With Autism Spectrum Disorder

OBJECTIVE. The purpose of this study was to empirically derive dimensions of activity participation among a sample of school-age children with autism spectrum disorder (ASD; n = 713). Additionally, we examined the associations between dimensions of activity participation and child characteristics (i.e., chronological age, autism severity, gender) and family demographics (i.e., maternal education)

To What Extent Do Joint Attention, Imitation, and Object Play Behaviors in Infancy Predict Later Communication and Intellectual Functioning in ASD?

The extent to which early social communication behaviors predict later communication and intellectual outcomes was investigated via retrospective video analysis. Joint attention, imitation, and complex object play behaviors were coded from edited home videos featuring scenes of 29 children with ASD at 9–12 and/or 15–18 months. A quantitative interval recording of behavior and a qualitative rating of the developmental level were applied. Social communication behaviors increased between 9–12 and 15–18 months. Their mean level during infancy, but not the rate of change, predicted both Vineland Communication scores and intellectual functioning at 3–7 years. The two methods of measurement yielded similar results. Thus, early social communicative behaviors may play pivotal roles in the development of subsequent communication and intellectual functioning

Perceptual metrics of individuals with autism provide evidence for disinhibition

Adults with autism exhibit inhibitory deficits that are often manifested in behavioral modifications, such as repetitive behaviors, and/or sensory hyper-responsiveness. If such behaviors are the result of a generalized deficiency in inhibitory neurotransmission, then it stands to reason that deficits involving localized cortical-cortical interactions – such as in sensory discrimination tasks – could be detected and quantified. This study exemplifies a newly developed method for quantifying sensory testing metrics. Our novel sensory discrimination tests may provide (a) an effective means for biobehavioral assessment of deficits specific to autism and (b) an efficient and sensitive measure of change following treatment. The sensory discriminative capacity of 10 subjects with autism and 10 controls was compared both before and after short duration adapting stimuli. Specifically, vibrotactile amplitude discriminative capacity was obtained both in the presence and absence of 1 sec adapting stimuli that were delivered 1 sec prior to the comparison stimuli. Although adaptation had a pronounced effect on the amplitude discriminative capacity of the control subjects, little or no impact was observed on the sensory discriminative capacity of the subjects with autism. This lack of impact of the adapting stimuli on the responses of the subjects with autism was interpreted to be consistent with the reduced GABAergic mediated inhibition described in previous reports. One significant aspect of this study is that the methods could prove to be a useful and efficient way to detect specific neural deficits and monitor the efficacy of pharmacological or behavioral treatments in autism

Aqueous-Base-Developable Benzocyclobutene (BCB)-Based Material -An Emerging Dielectric Material for Microelectronics

A self-priming and photosensitive aqueous-base-developable benzocyclobutene (BCB)-based dielectric material curable in air is described. The polymer is made from divinylsiloxane benzocyclobutene and BCB-acrylic acid. Patterned films have high resolution, and via openings are scum-free without a descum operation. Whether cured in nitrogen or in air, the formulation produces a film with optical, electrical, thermal, and mechanical properties desired for many microelectronic applications, such as packaging applications and a planarization layer or insulation layer in display applications

Contribution to the understanding of tribological properties of graphite intercalation compounds with metal chloride

Intrinsic tribological properties of lamellar compounds are usually attributed to the presence of van der Waals gaps in their structure through which interlayer interactions are weak. The controlled variation of the distances and interactions between graphene layers by intercalation of electrophilic species in graphite is used in order to explore more deeply the friction reduction properties of low-dimensional compounds. Three graphite intercalation compounds with antimony pentachloride, iron trichloride and aluminium trichloride are studied. Their tribological properties are correlated to their structural parameters, and the interlayer interactions are deduced from ab initio bands structure calculations

Psychometric Validation of the Sensory Experiences Questionnaire

We evaluated the psychometric properties of the Sensory Experiences Questionnaire (Version 1; Baranek, David, Poe, Stone, & Watson 2006), a brief caregiver questionnaire for young children with autismand developmental delays used to identify sensory processing patterns in the context of daily activities

Perceptual and Neural Response to Affective Tactile Texture Stimulation in Adults with Autism Spectrum Disorders

Autism spectrum disorders (ASD) are associated with differences in sensory sensitivity and affective response to sensory stimuli, the neural basis of which is still largely unknown. We used psychophysics and functional magnetic resonance imaging (fMRI) to investigate responses to somatosensory stimulation with three textured surfaces that spanned a range of roughness and pleasantness in a sample of adults with ASD and a control group. While psychophysical ratings of roughness and pleasantness were largely similar across the two groups, the ASD group gave pleasant and unpleasant textures more extreme average ratings than did controls. In addition, their ratings for a neutral texture were more variable than controls, indicating they are less consistent in evaluating a stimulus that is affectively ambiguous. Changes in brain blood oxygenation level-dependent (BOLD) signal in response to stimulation with these textures differed substantially between the groups, with the ASD group exhibiting diminished responses compared to the control group, particularly for pleasant and neutral textures. For the most unpleasant texture, the ASD group exhibited greater BOLD response than controls in affective somatosensory processing areas such as the posterior cingulate cortex and the insula. The amplitude of response in the insula in response to the unpleasant texture was positively correlated with social impairment as measured by the Autism Diagnostic Interview-Revised (ADI-R). These results suggest that people with ASD tend to show diminished response to pleasant and neutral stimuli, and exaggerated limbic responses to unpleasant stimuli, which may contribute to diminished social reward associated with touch, perpetuating social withdrawal, and aberrant social development