The relationship between the strength of the conditioned stimulus and the size of the resulting conditioned reflex / by P.S. Kupalov and W. Horsley Gantt.

  • Kupalov, P. S. (Petr Stepanovich), 1888-
Date:
[1926?]
Catalogue details

Licence: In copyright

Credit: The relationship between the strength of the conditioned stimulus and the size of the resulting conditioned reflex / by P.S. Kupalov and W. Horsley Gantt. Source: Wellcome Collection.

    5/14 (page 45)
    auditory stimuli: a metronome, an electric bell, or various musical tones, elicit a more speedy and abundant salivary response than do optical or cutaneous stimuli, such as flash-lights, images, scratching, &c. Least potent are thermal stimuli. On this basis laboratory stimuli were divided into strong (auditory) and weak (optical and cutaneous)’. O as -the rli* tfummd i Uil mi ii'iwinn One may assume that in the case of sound stimuli there is a greater amount of external energy transported to the peripheral receptors than in the case of cutaneous or thermal stimuli, and that as a result a nervous impulse of greater intensity is sent into the central nervous system in the former case. That the conditioned reaction depends upon the strength of the acting stimulus receives direct confirmation in the laboratory. Thus, it has been shown (Tichimirov and Zelony [6], [8], [9]), that in the response to a certain tone there is a greater reflex effect when the strength of the tone is increased, the pitch remaining constant, and a correspondingly smaller effect when the tone is weakened. This is true for other stimuli in the same analyser. Kasherinova [2] proved this for tactile and Orbeli [3] for optical stimuli. Zelony found that if a conditioned reflex be formed on a chord of several tones, a single tone of the chord elicits a weaker response than the whole cord. In the case of a chord composed of two tones of unequal strength, of the two tones tried separately the stronger is the more potent as a stimulus. Thus there are a number of observa¬ tions which indicate that the size of the conditioned reflex depends upon the physical strength of the stimulus. There are, however, other observations which suggest a relationship between stimulus and response of greater complexity than that outlined above. In the first place the application of weak stimuli, more particularly tactile and thermal, evokes a state of drowsiness in the animal. It is now possible to assert that the process of “internal inhibition” is the basis of the process of sleep, and, proceeding from this, we may suppose that the nervous elements of the skin and the thermal receptors of the cerebral cortex possess special functional properties. They cannot remain long in a state of excitation and pass quickly over into one of inhibition. Upon what factors this depends is too complex a question for discussion here. On what does the difference in the size of the reflex reaction to stimuli belonging to different analysers depend ? This difference was formerly explained as an expression of individual functional properties of the nervous elements of the different analysers in the cerebral cortex. It might be supposed, for example, that the nervous elements of the