Effects of apparatus adaptation and ethanol upon runway performance

Abstract

Rats given ethanol ran faster on the first 2 days of acquisition but slower on the last 2 days than placebo controls. However, when the 5s' fear of the apparatus was extinguished by prior exploration of the alley, alcohol 5s tended to run slower throughout training. It was concluded that alcohol improves performance in fear producing situations, but impairs performance when fear is reduced. 5s adapted to the apparatus ran faster throughout training than non-adapted 5s.A consistent finding is that Ss given ethanol run faster on early acquisition trials than do placebo controls (Barry, Wagner, & Miller, 1962;Nelson & Wollen, 1965) • Barry et al suggested that this may result from alcohol reducing the Ss I fear of the runway. If so, and if alcohol impairs performance in non-fearful situations, then the superiority of alcohol Ss should disappear if fear were extinguished by prior adaptation to the apparatus. This hypothesis was tested by comparing the performance of placebo and alcohol groups as a function of the presence or absence of free exploration of a runway.A second goal was to examine the effects of alcohol and adaptation upon speeds at the end of training. If fear extinguishes during training, and if alcohol impairs performance in non-fearful situations, placebo Ss should run faster at the end of training than Ss given alcohol. Moreover, adapted Ss should run faster than non-adapted Ss at the beginning of training, but no difference would be expected after sufficient training was given to extinguish the apparatus fear of nonadapted Ss. MethodThe Ss were 40 experimentally naive, male, hooded rats which ranged from 104 to 121 days of age on the first day of acquisition. Throughout the experiment, the Ss were maintained on a 23-hr. food and water deprivation schedule which permitted 1 hr. of ad lib consumption daily. The apparatus consisted of a 12-in. start box, a 36-in. runway, and a 12-in. goal box. The inside dimensions for each section were 3.5 in. wide by 4.7 in. high. The entire apparatus wa.s painted flat black except for a transparent plastic lid. The start and goal boxes were each separated from the alley by a manually-operated, black, guillotine door. An additional motor-operated, transparent door was located adjacent to the black manual start door but on the runway side.On the 7th through 14th day of deprivation, each S was handled for 2 to 3 min. and received 10 Noyes 97 mg reward pellets immediately prior to his daily Psychon. Sci .• 1966. Vol. 6 (7) feeding. On the 12th and 13th days of deprivation, Ss which were to be adapted to the apparatus were placed in the alley in groups of two or three and were allowed 1 hr. of free exploration each day with all doors raised and the clock starting and stopping as photobeams were intercepted. On the 14th day, each adapted S was placed alone in the apparatus for 15 min.Training began on the 15th day of deprivation and continued for 10 days. Each day began (about 1.5 hr. before the S's usual feeding time) with the administration of an alcohol (A) or a place...