Functional ultrasound (fUS) is a relatively new imaging modality to study the brain with a high spatiotemporal resolution and a wide field-of-view. In fUS detailed images of cerebral blood flow and volume are used to derive functional information, as changes in local flow and/or volume may reflect neuronal activation through neurovascular coupling. Most fUS studies so far have been performed in rats. Translating fUS to mice, which is a favorable animal model for neuroscience, pleads for a higher spatial resolution than what has been reported so far. As a consequence the temporal sampling of the blood flow should also be increased in order to adequately capture the wide range in blood velocities, as the Doppler shifts are inversely proportional to the spatial resolution. Here we present our first detailed images of the mouse brain vasculature at high spatiotemporal resolution. In addition we show some early experimental work on tracking brain activity upon local electrical stimulation.

The cardiac interpulse interval (IPI) has recently been proposed tofacilitate key exchange for implantable medical devices (IMDs) using apatient's own heartbeats as a source of trust. While this form of key exchangeholds promise for IMD security, its feasibility is not fully understood due tothe simplified approaches found in related works. For example, previouslyproposed protocols have been designed without considering the limitedrandomness available per IPI, or have overlooked aspects pertinent to arealistic system, such as imperfect heartbeat detection or the energy overheadsimposed on an IMD. In this paper, we propose a new IPI-based key-exchangeprotocol and evaluate its use during medical emergencies. Our protocol employsfuzzy commitment to tolerate the expected disparity between IPIs obtained by anexternal reader and an IMD, as well as a novel way of tackling heartbeatmisdetection through IPI classification. Using our protocol, the expected timefor securely exchanging an 80-bit key with high probability (1-10−6) is roughlyone minute, while consuming only 88 μJ from an IMD.