BROWeb: An interactive collaborative auditory environment on the world wide web

Presented at 3rd International Conference on Auditory Display (ICAD), Palo Alto, California, November 4-6, 1996.We describe an infrastructure for a real-time shared auditory environment on the World Wide Web (WWW). The system consists of the BROWeb "star-shaped" Web server and the StarClient Java class and interface. The BROWeb server is designed to facilitate implementation of Java applets wherein users see and hear each other's activity. Developed as an interactive music system for public performance, BROWeb is robust enough to support hundreds of users in a demanding application. We also discuss design issues regarding the actual experiences that a Java applet overlying this infrastructure can deliver. We created, for instance, a privileged user–a "director"–who can make decisions affecting the overall system's performance and also the data streams from other users. As for the sound source of the actual experience, we present two alternatives that we have tested: local sounds that download when the experience begins and streamed audio (RealAudio, Xing, or other network broadcasting tool)

Introduction: Evolution of Brain-Computer Interfaces

International audienceBrain-Computer Interfaces (BCIs) are systems that translate a measure of a user‘s brain activity into messages or commands for an interactive application. A typical example of a BCI is a system that enables a user to move a ball on a computer screen towards the left or towards the right, by imagining left or right hand movement respectively. The very term BCI was coined in the 70’s, and since then, interest and research efforts in BCIs grew tremendously, with possibly hundreds of laboratories around the world studying this topic. This has resulted in a very large number of paradigms, methods, concepts and applications of such technology. This handbook thus aims at providing an overview and tutorials of the multiple and rich facets of BCIs.As an introduction to this vast endeavor, we would like to present a short and brief history of BCIs, in order to explain where they come from. Since we are no historians of science, such historical introduction is likely to be incomplete and biased, according to our background, views and (conscious or not) preferences. Nonetheless, we hope this will enable the readers to get a quick overview of the development in BCIs these last 30 or 40 years, and will motivate them to learn more about BCI concepts, which this handbook should make easier

Cellular correlates of sensory processing in the mammalian audio-vestibular brainstem

Efferent projections to the vestibular inner ear organs have remained elusive. To shed light on their physiological role, a first investigation of the vestibular efferent (VE) neurons in the brainstem was undertaken by using a transgenic mouse which expresses a fluorescent marker in the VE neurons. The intrinsic electrical properties of VE neurons were compared to those of the lateral olivocochlear (LOC) brainstem neurons, which innervate the cochlea. The study demonstrated that, due to more complex expression of potassium-based conductances, VE neurons display a more bimodal firing pattern than LOC neurons, which indicates that their role may be more widespread and control both motion and gravity sensors (Paper I). This thesis next investigated the cellular properties of the superior paraolivary nucleus (SPON) neurons in normal (Paper II and III) and congenitally deaf (Paper IV) mice. This evolutionary conserved mammalian brainstem structure has been implicated in the processing of speech cues by extracting the temporal signal in coarse sound amplitude fluctuations or brief sound segments, by responding abruptly to the offset of a tone stimulus or by entrainment to slow amplitude modulations of the same tone. Patch-clamp recordings in brain slices revealed that all SPON neurons exhibit postinhibitory rebound spiking, generated by the subthreshold-activated h current and low voltage-activated calcium current of the T-type. Pharmacological blockade of these currents in vivo abolished the sound-induced offset response and sensitivity to amplitude modulated tones, providing evidence that rebound spiking is the mechanism for offset-spiking in SPON (Paper II). In addition to a powerful inhibitory input, SPON was also confirmed to receive a single excitatory input from the octopus cells (Paper III) – held to be the most temporally precise neurons in the brain, responding with extremely high precision to complex sounds. A selective, strong projection from the octopus cells can also explain why SPON responds to the onset of sounds and is compatible with the idea that there are specialized brain circuits that encode the slow temporal rhythm contained in natural sounds, such as speech. The robustness of these brain circuits was demonstrated in SPON of congenitally deaf mice. Despite the absence of input activity, the deaf SPON neurons developed normal capacity for well-timed rebound spiking. This remarkable rescue of the SPON cellular function may have been possible due to up-regulation of the neuroprotective factor neuritin, prolonging the developmental time window (Paper IV). In summary, this thesis demonstrates, on a cellular level, how combinations of different voltage-gated ion channels that are activated by excitation or inhibition or both, can create distinct firing patterns in sensory neurons that encode selective features of the incoming afferent signal. This code will either project back to control the sensory receptors or feed into higher order brain areas where it contributes to the hierarchical processing that enable us to perceive and comprehend a sensatio