Abstract: Multifunctional microelectronics fiber probes can be chronically implanted in tissue of awake-behaving animals for understanding brain-viscera communication. These fiber probes can be made using thermal drawing to make hundreds of meters of flexible fiber that incorporates features such as light sources, electrodes, thermal sensors, and microfluidic channels in a multilayered configuration. The fiber mechanics can be tuned for two distinct device layouts: (1) higher-modulus, flexible brain fibers for implantation into deep-brain; and (2) soft, compliant gut fibers for implantation into the small intestine. Brain fibers can modulate the deep-brain mesolimbic reward pathway. Gut fibers can perform peripheral optogenetic stimulation of vagal afferents from the intestine to stimulate brain reward neurons.

Abstract: A surgical metal detection apparatus. The apparatus comprises an elongate, tubular cannula and a removable element, which may be a trocar, releasably engaged within the cannula. A metal detection coil is positioned within the removable element or, in some embodiments, within the cannula. The metal detection coil is connected to a metal detection circuit which is adapted to detect the presence of a metallic element proximate to the end of the removable element or cannula. When a metallic element has been detected, the removable element may be removed from the cannula to permit the passage of a removal tool, such as a screwdriver, through the cannula without removing or changing the position of the cannula.