抄録
The purpose of this paper was to examine the fact that extinction of ICSS (intracranial self-stimulation) is abnormally rapid and to test the drive-decay theory proposed by Deutsch.
Exp. 1) Five groups of five white rats each with posterior hypothalamic electrodes were permitted to self-induce electric stimulation, 500, 1000, 2000, 4000, 8000 times, respectively in the Skinner box. Immediately after a series of self-stimulation, they were given extinction trials in which they received no electrical stimulus even if the lever was pressed.
All subjects stopped responding as rapidly as previous studies have reported, but they only continued to press the lever in proportion to the number of reinforced stimuli within one minute after extinction started.
Exp. 2) The procedure was almost the same as that of Exp. 1 except for the extinction trials. All subjects spent 24 hours in their home cages from the last reinforced stimuli until they received extinction trials.
Results indicated that the number of reinforced stimuli only had a significant effect upon extinction resistance within one minute after extinction trials started. It was also shown that responses for hypothalamic stimulation disappeared more rapidly in extinction which was given 24 hours later than in immediate extinction.
In both experiments, spontaneous recovery took place in the extinction process of ICSS.
Thus the drive-decay theory of extinction of ICSS was only partially demonstrated.
