In vivo Recording Quality of Mechanically Decoupled Floating Versus Skull-Fixed Silicon-Based Neural Probes

Throughout the past decade, silicon-based neural probes have become a driving force in neural engineering. Such probes comprise sophisticated, integrated CMOS electronics which provide a large number of recording sites along slender probe shanks. Using such neural probes in a chronic setting often requires them to be mechanically anchored with respect to the skull. However, any relative motion between brain and implant causes recording instabilities and tissue responses such as glial scarring, thereby shielding recordable neurons from the recording sites integrated on the probe and thus decreasing the signal quality. In the current work, we present a comparison of results obtained using mechanically fixed and floating silicon neural probes chronically implanted into the cortex of a non-human primate. We demonstrate that the neural signal quality estimated by the quality of the spiking and local field potential (LFP) recordings over time is initially superior for the floating probe compared to the fixed device. Nonetheless, the skull-fixed probe also allowed long-term recording of multi-unit activity (MUA) and low frequency signals over several months, especially once pulsations of the brain were properly controlled

Interconnect for Out-of-plane MEMS

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Active sound reduction system and method

The present invention refers to an active sound reduction system and method for attenuation of sound emitted by a primary sound source, especially for attenuation of snoring sounds emitted by a human being. This system comprises a primary sound source, at least one speaker as a secondary sound source for producing an attenuating sound to be superposed with the sound emitted by said primary sound source, a reference microphone for receiving sound from said primary sound source, and at least one error microphone being allocated to each speaker to form a speaker/microphone pair. The at least one error microphone is provided as a directional microphone pointing at its allocated speaker to receive residual sound resulting from the superposition of the sounds from the primary sound source and the corresponding speaker.; The error microphone and speaker of at least one speaker/microphone pair and the primary sound source are arranged substantially collinear. A control unit is provided to receive an output reference signal of the reference microphone representing the sound received by the reference microphone and an output error signal of the at least one error microphone representing the sound received by the at least one error microphone and to calculate a control signal for the speaker from the output reference signal and the output error signal

LIMPACT:A Hydraulically Powered Self-Aligning Upper Limb Exoskeleton

The LIMPACT is an exoskeleton developed to be used in identifying the reflex properties of the arm in stroke survivors. Information on joint reflexes helps in designing optimal patient specific therapy programs. The LIMPACT is dynamically transparent by combining a lightweight skeleton with high power to weight ratio actuators. The LIMPACT is supported by a passive weight balancing mechanism to compensate for the weight of the exoskeleton and the human arm. Various self-aligning mechanisms allow the human joint axes to align with the axes of the exoskeleton which ensure safety and short don/doff times. The torque-controlled motors have a maximum torque bandwidth of 97 Hz which is required for fast torque perturbations and smooth zero impedance control. The LIMPACT's weight is reduced five times as gravitational forces are lowered using a model-based gravity compensation algorithm. The impedance controller ensures tracking of a cycloidal joint angle reference. A cycloid with an amplitude of 1.3 rd and a maximum velocity of 6.5 rd/s has a maximum tracking error of only 7%. The LIMPACT fulfills the requirements to be used in future diagnostics measurements for stroke patients

Approaches for drug delivery with intracortical probes

Abstract Intracortical microprobes allow the precise monitoring of electrical and chemical signaling and are widely used in neuroscience. Microelectromechanical system (MEMS) technologies have greatly enhanced the integration of multifunctional probes by facilitating the combination of multiple recording electrodes and drug delivery channels in a single probe. Depending on the neuroscientific application, various assembly strategies are required in addition to the microprobe fabrication itself. This paper summarizes recent advances in the fabrication and assembly of micromachined silicon probes for drug delivery achieved within the EU-funded research project NeuroProbes. The described fabrication process combines a two-wafer silicon bonding process with deep reactive ion etching, wafer grinding, and thin film patterning and offers a maximum in design flexibility. By applying this process, three general comb-like microprobe designs featuring up to four 8-mm-long shafts, cross sections from 150×200 to 250×250 µm², and different electrode and fluidic channel configurations are realized. Furthermore, we discuss the development and application of different probe assemblies for acute, semichronic, and chronic applications, including comb and array assemblies, floating microprobe arrays, as well as the complete drug delivery system NeuroMedicator for small animal research.status: publishe