The term “glass-cylinder seeking drive” (GCSD) was coined by Joseph Knoll, in 1969, in his monograph entitled The Theory of Active Reflexes. The glass-cylinder is a 30 cm high, 16 cm (bottom) to 12 cm (top) wide cylinder-shaped open box, with a metal plate on the bottom and a side opening, through which a rat of  up to 350 to 400 g body weight can enter (Knoll 1956; Knoll and Knoll 1958). The GCSD is based on a conditioned motor (avoidance) reflex in which rats are conditioned to jump to the upper rim of a glass cylinder to an auditory (sound of a bell) conditional stimulus (CS) to “escape” burning heat (60 degree Celsius), the unconditional stimulus (US) delivered via the metal plate at the bottom of the cylinder. Rats acquired the GCSD, jump to the upper rim of the cylinder as soon as placed into the cylinder, even without the sound of a bell (CS) by developing a second order visual conditional (chain) reflex to the glass cylinder itself. The GCSD is so strong, that even if there is a receptive female and/or food at the bottom of the cylinder, rats ushered into the cylinder jump to the ceiling of the cylinder. In some rats, the GCSD qualifies for an ”in-extinguishable active reflex” that is retained for lifetime (Knoll 2014). Knoll (1969, 2005) perceives GCSD as a specific acquired drive, an unnatural urge that overrides innate drives, such as hunger or sexual drives. GCSD was initially employed in a series of behavioral pharmacological studies conducted with centrally acting drugs by Knoll (1968) in the late 1950s and 1960s. After the demonstration by Berta Knoll, in 1961, that GCSD cannot be acquired in the mouse the study of GCSD became central to Knoll’s research in the evolution of homo sapiens. The findings of this research and the conceptualization of these findings were presented by Knoll (2005) in his monograph, The Brain and Its Self (Knoll 2014).

Knoll J. Experimental studies on the higher nervous activity of animals. V. The functional mechanism of the active conditioned reflex. Acta Physiologica Hungarica 1956; 10:89-100.

Knoll J. The Theory of Active Reflexes. An Analysis of Some Fundamental Mechanisms of Higher Nervous Activity. Budapest/New York:  Publishing House of the Hungarian Academy of Sciences. Hafner Publishing Company; 1969, pp. 54-63.

Knoll B.  Certain aspects of the formation of temporary connections in comparative experiments on mice and rats. Acta Physiologica Hungarica 1961; 20:265-275

Knoll B (1968) Comparative physiological and pharmacological analysis of the higher nervous function of mice and rats (in Hungarian). Thesis. Budapest: Hungarian Academy of Sciences; 1968

Knoll J (2005) The Brain and Its Self. A Neurochemical Concept of the Innate and Acquired Drives. Springer/Berlin, Heidelberg, New York; 2005. (inhn. Books, January 23, 2014).

Knoll J. Active reflex. inhn.org. Dictionary, March 27, 2014. 

Knoll J, Knoll B. Methode zur Untersuchung der spezifisch depressiven Wirkung von

“Tranquilizern” auf das Zentralnervensystem I. Arzneimittel-Forschung 1958; 8: 330-333.

Joseph Knoll

April 10, 2014