Cherenkov-phase-matched nonlinear optical detection and generation of terahertz radiation via GaAs with metal-coating.

Terahertz (THz) wave detection and emission via Cherenkov-phase-matched nonlinear optical effects at 1.55-µm optical wavelength were demonstrated using a GaAs with metal-coating (M-G-M) and bare GaAs as a reference sample in conjunction with a metallic tapered parallel-plate waveguide (TPPWG). The metal-coated GaAs is superior to the bare wafer both as a THz electro-optic detector and as an emitter. Significant improvements in the detection and emission efficiency were obtained by utilizing a metal-coating due to better confinement and lower loss of the THz waves propagating in the M-G-M compared with bare GaAs.

A cross-species socio-emotional behaviour development revealed by a multivariate analysis.

Recent progress in affective neuroscience and social neurobiology has been propelled by neuro-imaging technology and epigenetic approach in neurobiology of animal behaviour. However, quantitative measurements of socio-emotional development remains lacking, though sensory-motor development has been extensively studied in terms of digitised imaging analysis. Here, we developed a method for socio-emotional behaviour measurement that is based on the video recordings under well-defined social context using animal models with variously social sensory interaction during development. The behaviour features digitized from the video recordings were visualised in a multivariate statistic space using principal component analysis. The clustering of the behaviour parameters suggested the existence of species- and stage-specific as well as cross-species behaviour modules. These modules were used to characterise the behaviour of children with or without autism spectrum disorders (ASDs). We found that socio-emotional behaviour is highly dependent on social context and the cross-species behaviour modules may predict neurobiological basis of ASDs.

[Development and neural basis of social behavior].

We have developed a multi variate analysis of social communication behavior which allows for discriminating the emotional state of an agent interacting with other agents (Bouquet method). Domestic chick or common marmoset was reared under socially isolated conditions, later tested for its development of communication behavior with peers by Bouquet, and compared with that of animals reared under grouping conditions. We found the existence of high sensitive period for social interaction, given less experience, developing less affiliated behavior. From chick model, a couple of neuronal difference was observed between two groups, amygdale core central cell size, MRI volumetric measure in mesolimbic area, and gene expression patter including brain type tryptophan hydroxylase in nucleus accumbens. The isolated chick behavior changed better to be socially affiliated by taking SSRI/SNRI or Ubiquinol (the reduced form of CoQ10) together with social interaction experience after the sensitive period. Finally, we could discriminate the behavior of Asperger syndrome children (n = 7) from that of the typically developed siblings (n = 6) during the clinical interview by applying Bouquet method.