For a short time, when the University of Vienna closed he studied in Constantin von Monakow's Institute of Brain Anatomy, where Hayek spent much of his time staining brain cells. Hayek's time in Monakow's lab and his deep interest in the work of Ernst Mach inspired his first intellectual project, eventually published as "The Sensory Order" (1952). It located connective learning at the physical and neurological levels, rejecting the "sense data" associationism of the empiricists and logical positivists. Hayek presented his work to the private seminar he had created with Herbert Furth called the Geistkreis.