Learning and retention of a shock avoidance task were studied in the absence of proprioceptive or other topographic feedback. Rats with a deafferented hind limb were trained using the instrumental shock avoidance and retention paradigm of Horridge. Rats received shock whenever they lowered an electrode attached to a deafferented hind foot into an electrolyte bath; yoked-control rats received the shocks to a deafferented hind food along with the experimental animals. Experimental animals consistently held their feet above the electrolyte (p<0.01). During the early minutes of the second phase (a testing situation, in which the experimental and control animals were both shocked for leg lowering) the experimentals received fewer shocks than the controls (p<0.001); the controls eventually withheld their feet (p<0.001). These results indicate that rats with deafferented hind limbs provide a simple system for the study of learning and retention in the absence of proprioceptive or other topographic feedback.
Bibliographical noteFunding Information:
Rats with one hind leg deafferented were trained using the Horridge paradigm. Horridge found that headless insects could learn to hold a leg up to avoid shock \[7\].T here were two major advantages of the Horridge paradigm. First, it included a yoked control. Second, it used instrumental avoidance conditioning which is usually considered a very efficient form of learning \[2\]. The Horridge paradigm is composed of two parts. In the first or learning situation, the control and the experimental animals receive shocks dependent on the leg position of the experimental animal. The second stage is the testing situation; the control and the experimental animals each receive shocks dependent on ~This research was partially supported by General Research Support funds (UCI 71-27, H-71-56 and 72-11) of the California College of Medicine and by a National Science Foundation Summer Research Fellowship (NSF GV-10031 (4/31/73)) given to Steven C. McLoon.
- Horridge paradigm
- Learning and retention
- Shock avoidance task