Unsupervised cross-lingual speaker adaptation for HMM-based speech synthesis using two-pass decision tree construction

This paper demonstrates how unsupervised cross-lingual adaptation of HMM-based speech synthesis models may be performed without explicit knowledge of the adaptation data language. A two-pass decision tree construction technique is deployed for this purpose. Using parallel translated datasets, cross-lingual and intralingual adaptation are compared in a controlled manner. Listener evaluations reveal that the proposed method delivers performance approaching that of unsupervised intralingual adaptation

Tetracycline Inducible Gene Manipulation in Serotonergic Neurons

The serotonergic (5-HT) neuronal system has important and diverse physiological functions throughout development and adulthood. Its dysregulation during development or later in adulthood has been implicated in many neuropsychiatric disorders. Transgenic animal models designed to study the contribution of serotonergic susceptibility genes to a pathological phenotype should ideally allow to study candidate gene overexpression or gene knockout selectively in serotonergic neurons at any desired time during life. For this purpose, conditional expression systems such as the tet-system are preferable. Here, we generated a transactivator (tTA) mouse line (TPH2-tTA) that allows temporal and spatial control of tetracycline (Ptet) controlled transgene expression as well as gene deletion in 5-HT neurons. The tTA cDNA was inserted into a 196 kb PAC containing a genomic mouse Tph2 fragment (177 kb) by homologous recombination in E. coli. For functional analysis of Ptet-controlled transgene expression, TPH2-tTA mice were crossed to a Ptet-regulated lacZ reporter line (Ptet-nLacZ). In adult double-transgenic TPH2-tTA/Ptet-nLacZ mice, TPH2-tTA founder line L62-20 showed strong serotonergic β-galactosidase expression which could be completely suppressed with doxycycline (Dox). Furthermore, Ptet-regulated gene expression could be reversibly activated or inactivated when Dox was either withdrawn or added to the system. For functional analysis of Ptet-controlled, Cre-mediated gene deletion, TPH2-tTA mice (L62-20) were crossed to double transgenic Ptet-Cre/R26R reporter mice to generate TPH2-tTA/Ptet-Cre/R26R mice. Without Dox, 5-HT specific recombination started at E12.5. With permanent Dox administration, Ptet-controlled Cre-mediated recombination was absent. Dox withdrawal either postnatally or during adulthood induced efficient recombination in serotonergic neurons of all raphe nuclei, respectively. In the enteric nervous system, recombination could not be detected. We generated a transgenic mouse tTA line (TPH2-tTA) which allows both inducible and reversible transgene expression and inducible Cre-mediated gene deletion selectively in 5-HT neurons throughout life. This will allow precise delineation of serotonergic gene functions during development and adulthood

Exploring the potential of EEG for real-time interactions in immersive virtual reality

Abstract Brain-computer interfaces (BCIs) can use data from non-invasive electroencephalogram (EEG) to transform different brain signals into binary code, often aiming to gain control utility of an end-effector (e.g mouse cursor). In the past several years, advances in wearable and immersive technologies have made it possible to integrate EEG with virtual reality (VR) headsets. These advances have enabled a new generation of user studies that help researchers improve understanding of various issues in current VR design (e.g. cybersickness and locomotion). The main challenge for integrating EEG-based BCIs into VR environments is to develop communication architectures that deliver robust, reliable and lossless data flows. Furthermore, user comfort and near real-time interactivity create additional challenges. We conducted two experiments in which a consumer-grade EEG headband (Muse2) was utilized to assess the feasibility of an EEG-based BCI in virtual environments. We first conducted a pilot experiment that consisted of a simple task of object re-scaling inside the VR space using focus values generated from the user’s EEG. The subsequent study experiment consisted of two groups (control and experimental) performing two tasks: telekinesis and teleportation. Our user research study shows the viability of EEG for real-time interactions in non-serious applications such as games. We further suggest that a simplified way of calculating the mean EEG values is adequate for this type of use. We, in addition, discuss the findings to help improve the design of user research studies that deploy similar EEGbased BCIs in VR environments