The term "conditioning stimulus" has been used by neurophysiologists to refer to stimuli delivered to a nerve or nucleus prior to testing the response of a neuron to other afferent input. The term was used by JC Eccles and others. What is the rationale behind the use of this term rather than let's say just electrical stimulation or stimulus pairing or something else? Has the use of this term ever been defined?
Dear Nikolaos,
I think when a supra-threshold stimulus applied to a nerve/axons that results in an acute response in postsynaptic cells, but also has a lasting (chronic) effect that modifies the response of the postsynaptic cells to a second or third stimulus applied subsequently. Therefore the first stimulus is referred as conditioning stimulus. The rationale is that when you apply repetitive or multiple stimulation with a short delay the postsynaptic responses will be modified/conditioned by the previous stimulations/experiences.
best wishes,
Refik
Thank you Refik, I like your description. I am looking for a reference where the term was first introduced and defined.
Dear Nikolaos, as far as I understand from your question you could not find a clear definition for the term “conditioning stimulus” in neurophysiological experiments. I agree with you that it might be very difficult to find a clear definition, because I think this term was transferred from behavioral experiments in psychology without additional clear definition to electrical stimuli in neurophysiological experiments. Basically Aristotle seemed to be the first who observed the need for repeating sequences of activation in order to link for example mental representations (see “A History of Spike-Timing-Dependent Plasticity” Henry Markram, Wulfram Gerstner, and Per Jesper Sjöström, Front Synaptic Neurosci. 2011; 3: 4. Published online 2011 Aug 29). As far as I know the first scientist who used the term “conditioning” in life sciences was Pavlov, who published his results in 1897. As you know in his experiments human and animal subjects changed the magnitude and timing of their conditioned response, as a result of the dependency between the “conditioned stimulus” and the “unconditioned stimulus”, which both were not electrical stimuli. Later this term was used for stimuli that were electrical in their nature for electrophysiological experiments. In electrophysiological experiments “conditioning” occurs when the “conditioning stimulus” is a stimulus that itself causes a neural response. In a behavioral experiment the conditioning stimulus is a stimulus to which the subject is unresponsive until the association with the unconditioned stimulus is established. So this means that the use of the term “conditioning stimulus” for effects in neurophysiological experiments needs a further and more clear definition. Although Pavlov´s work on classical conditioning is well known, his work on the central nervous system is not so well known. In the last 30 years of his life Pavlov was investigating cortical processes by salivary reflex conditioning, a method he used to develop his theory of higher nervous activity (details see “The neurophysiological aspects of Pavlov's theory of higher nervous activity: in honor of the 150th anniversary of Pavlov's birth” Grimsley DL, Windholz G., J Hist Neurosci. 2000 Aug. 9(2):152-63.). Maybe he has defined the term “conditioning stimulus” also for the use of electrical stimuli in the cns. It might be helpful to further study his work. One problem in former times was that main parts of Pavlov´s scientific work (and other scientists from Germany, France, Spain, etc.) was not available in English language until 1927 when it was translated and authorized by Pavlov (see “A neuroscientist´s guide to classical conditioning, John W. Moore, Editor, Springer, 2002, page 4). Although I have not read this book completely but maybe it helps you to find a definition for the term in neurophysiological experiments. If you should find a definition I really would appreciate if you could send me this information. Many thanks in advance. Best wishes, Dirk
read "conditional probability theory" so that you can understand theoretically and practically about "conditioning stimulus" . you don`t have to bother that much about such a small issue. please post (I mean e-mail to [email protected]) the paper in which you encountered the term "conditioning stimulus". So that I can better answer you.
you can refer
Probability, Random Variables, and Random Processes: Theory and Signal Processing Applications
John J. Shynk
ISBN: 978-0-470-24209-4
794 pages
October 2012
Also you can refer for a more mathematical comprehension
probability, random variables and random signal principles by Peyton Z. Pebbles JR. mc-Graw-Hill Publi, 2001
Mr Hoehl,
Thank you for your thoughtful answer. The term conditioning stimulus may have nothing to do with the term conditioned stimulus in Pavlovian conditioning, although it is worth finding out if Pavlov used it and I am grateful for the lead you gave me. The earliest use of the term in neurophysiology I have been able to establish was by Eccles et al (1957) Synaptic actions, etc. J Physiol 136:527-546. There it is written: "the usual procedure was adopted of applying double stimuli to the muscle nerve (cf. Bradley & Eccles , 1953, etc), the first or conditioning stimulus being varied in strength ...". The term does not appear in the earlier paper (Bradley & Eccles, 1953). There is some similarity with Pavlovian conditioning in that the conditioning stimulus can change the efficacy of the testing stimulus. It is possible that the term was never properly defined, unless Pavlov used it in some similar context.
It is interesting that the term is also used in conditional probability theory. There are obviously more concepts than unique words to express them.
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