RECORDING FROM SINGLE NEURONS IN THE BRAIN FOR LONG PERIODS OF TIME HAS BEEN A CENTRAL GOAL OF BOTH BASIC NEUROSCIENCE AND TRANSLATIONAL NEUROLOGY IN ORDER TO UNDERSTAND BRAIN PROCESSES SUCH AS LEARNING CITEPLACEHOLDER1ID. RECENT ADVANCES IN MATERIALS ENGINEERING, DIGITAL SIGNAL ACQUISITION, AND ANALYSIS ALGORITHMS HAVE BROUGHT US CLOSER TO ACHIEVING THIS GOAL, AND THE POSSIBILITY HAS GATHERED MUCH PUBLIC ATTENTION CITEPLACEHOLDER2ID. HOWEVER, IT REMAINS A CHALLENGE TO RECORD FROM THE SAME UNITS FOR WEEKS TO MONTHS. HERE, WE RECORD MANY HIGH-QUALITY JUXTACELLULAR TETRODE NEURONAL SIGNALS RELIABLY OVER LONG PERIODS OF TIME IN BOTH DEEP AND SUPERFICIAL AREAS OF THE BRAIN. WE ACHIEVE THIS BY COMBINING ELECTROCHEMICAL ROUGHENING AND CARBON NANOTUBE COATING OF A FLEXIBLE PLATINUM/IRIDIUM SUBSTRATE. THE MATERIAL PROPERTIES OF THIS COATING WERE CHARACTERIZED, AND PACKAGING AND INSERTION TECHNIQUES WERE OPTIMIZED TO MINIMIZE TIP MOVEMENT WITH BRAIN PULSATION. THIS "MAGDEBURGER" PROBE ENABLES RECORDINGS WITH LONG-TERM SIGNAL STABILITY AND HIGH SIGNAL-TO-NOISE RATIO AT A REASONABLE COST IN BOTH RODENT AND PRIMATE BRAINS. ROBUST TRACKING OF IDENTIFIED NEURONS OVER LONGER TIME PERIODS, IN MULTIPLE INDEPENDENTLY TARGETED AREAS OF THE BRAIN, WILL ALLOW FUNDAMENTAL ADVANCES IN THE STUDY OF COGNITIVE LEARNING, AGING, AND PATHOGENESIS, AND OPENS NEW POSSIBILITIES FOR BRAIN INTERFACES IN HUMANS.