Guillotine Door Research Articles

Goal vs. alley punishment after escape training: Massed trials and startbox conditions

Two different starting procedures, drop box vs. guillotine door, were used in giving 36 male rats 20 massed shock-escape trials in a straight runway. On subsequent trials, the animals encountered no shock at all, shock punishment in the middle 2 ft of the 4-ft alley, or shock for.5 sec immediately after entering the goalbox. The guillotine-door procedure produced faster running in extinction, alley punishment facilitated responding, and goal punishment sup- pressed responding. Results were interpreted in terms of stimulus-directive effects, as modified by massing vs. spacing trials.

Pseudoavoidance responses in two-way avoidance learning

In a two-way avoidance learning task, responses sometimes occur during the CS-UCS inter­ val prior to the initial receipt of shock. The number of such pseudoavoidance (P A) responses was found to be related positively to the number of avoidance responses made after the receipt of shock, implying that some of these avoidance responses were artifactual. The use of pro­ cedures that would decrease the occurrence of P A responses would also minimize this possible contamination of the avoidance data. Evidence was presented indicating that the frequency of P A responses was decreased when some amount of exploration of the apparatus, rather than none, was given prior to avoidance training, the shuttle compartments were separated by a small rather than a large guillotine door. a neutral rather than an intense auditory CS was used. and the CS-UCS interval was short (5 sec) rather than long (10 sec). In previous investigations of two-way avoidance learning in this laboratory, it was rare to observe a sub­ ject locomote from one compartment to the other during the CS-UCS interval before the ftrst shock was received. The compartments of the apparatus employed in these studies were separated by a small guillotine door resting on a hurdle, and the procedure involved some exploration of the apparatus prior to avoidance training. When the size of the door and the exploration treatment were altered in a recent study (McAllister, McAllister, Dieter, & James, in press, Experiment 2), a large number of such responses were observed. The purpose of this paper is to present the data from the above study that relate to such pseudoavoidance (P A) responses, as well as to identify in other studies the experimental conditions that have led to such responses. Knowledge of the variables leading to PA responses would enable investigators to choose conditions that minimize their occurrence. This is important because, although a PA response does lead to the nonoccurrence (avoid­ ance) of shock, it clearly is not made as a consequence of learning. Within two-factor theory, an avoidance response is assumed to be an escape-from-fear response. Obviously, a response made during the CS-UCS interval prior to the initial receipt of shock cannot be considered an escape from conditioned fear. Similarly, from a cognitive viewpoint (e.g., Seligman & Johnston, 1973), an avoidance response made prior to the receipt of the ftrst shock cannot be the result of the subject's expect­ ancy that shock will occur if the response is not made.

Effects of differential cue availability in an active avoidance CS for young and adult rats

In Experiment I, groups of 22-and 140+-day rats were trained in acquisition and extinction of 1-way avoidance with a CS that consisted of the opening of a guilotine door 5 sec before US onset or a combination of door-opening plus a tonal signal that remained on until the occurrence of the motor response. Under both CS conditions, avoidance acquistion was similar at each age level. The extinction date indicated comparable performance for the young subjects but differential performance and greater resistance to extinction for the adult subjects. Adults trained with the door-opening CS persisted in responding for an entire series of 100 extinction trials, whereas the adults trained with the compound CS extinguished well within the 100-trial, whereas the adults trained with the compound CS extinguished well within the 100-trial limit. A 2nd experiment included 10 pre-exposures of the simple or compound CS's prior to avoidance training. Although the pups were insensitive to pre-exposure effects, the adults that were pre-exposed and trained with identical CS's showed evidence of pre-exposure effects. Results of both experiments were interpreted as indicative of differential cue saliency between ages.

Caudate nucleus lesions impair spontaneous alternation.

I t has been reported that rats with caudate nucleus lesions rarely display the exploratory responses or the reactivity to novel environmental stimuli generally observed in intact animals ( 5 ) . TO investigate further the effect of caudate nucleus lesions on exploratory behavior, we tested caudectomized and control rats on spontaneous alternation. Ss were 38 Sprague-Dawley rats. Fifteen rats received bilateral lesions to the caudate nucleus-putamen complex, 8 rats received bilateral lesions to the posterior cortex, and 1 5 rats served as unoperated controls. Surgical technique and histological evaluation have been outlined in an earlier paper ( 3 ) . Prior to the present experiment all Ss had been tested on a series of avoidance tasks ( 3 ) . A minimum of 25 days elapsed between the final avoidance trials and the commencement of alternation testing. In the T maze, described previously ( 4 ) , each S was given two trials daily for three days. A trial commenced when S was placed in the startbox. Three sec. later the guillotine door was raised and S allowed to enter the maze. A four-footed entry into either side of the T completed the trial. S was immediately returned to the startbox for the second trial. If an animal failed to respond within a 3-min. time limit the trial was terminated and that day's results discounted. The unoperated control group alternated significantly above chance (82.9%, x2 = 7.8, df = 1, P < .01, two-tailed); however, both the caudate lesioned group (44.2%) and the cortically lesioned group (72.0%) performed randomly. The caudate lesioned group alternated significantly less than either the unoperated control group (Xa = 13.6, df = 1, P < ,001, two-tailed) or the cortical control group ( X 3 = 3.9, df = 1, P < .O5, two-tailed). The performances of the control groups were not significantly differenr. O f the 1 5 caudate rats, 1 alternated on all three occasions, 6 on two occasions, 4 on one, and 4 not at all. Percentages of failures to leave the startbox within the 3-min. time limit (caudate, 4.5%; cortical control, 3.7%; unoperated control, 4.5%) were not significantly different. This suggests that the differences in alternation were not caused by differences in emotionality as reflected in the freezing response. Whether the spontaneous alternation deficits observed following bilateral lesioning of the caudate nucleus resulted from increased perseverative tendencies ( 2 ) , removal of inhibitory processes ( I ) , or disruption of the neural mechanisms involved in the acquisition and integration of sensory information (4 ) awaits further investigation.

The effects of age and CS complexity on the acquisition of an avoidance response in rats

Two groups of 25 day old and two groups of 95–105 day old rats were used to investigate the effects of age and CS complexity on the acquisition of a one way avoidance response. A group at each age was trained using the opening of a guillotine door as the CS, and a group at each age was trained using the opening of a guillotine door and onset of a buzzer as the CS. Ss trained with the buzzer and opening of the guillotine door CS met the learning criterion in significantly fewer trials than Ss trained using only the opening of the guillotine door as the CS. There was no significant effect of age or interaction of age with CS complexity on trials to criterion.

OLFACTORY DISCRIMINATION LEARNING IN THE VIRGINIA OPOSSUM

As in other marsupials, the brain of the Virginia opossum (Didelphis virginiana) has no corpus callosum connecting the cerebral hemispheres, making it suitable for splitbrain experiments of interhemispheric communication (Herring, Mason, Doolittle, & Scarrett, 1966). In previous split-brain experiments done on rats, cats, and monkeys, the sensory modalities of touch and vision were studied. In the opossum, however, neither of these modalities was suitable due to the bilateral cortical representarion of touch stimuli and the inaccessibility of the optic chiasm which must be sectioned in vision srudies (Lende, 1963). T he sensory modality of olfaction was chosen for study because of the accessibility of the olfactory bulbs and the availability of data on techniques of electrophysiological recording from the olfactory bulbs of opossums (Phillips, 1962). To test the practicality of using olfaction to study interhemispheric communication, in the present study we attempted to teach opossums an olfactory discrimination. Method.-Four adult Virginia opossums, one male and three females, were Ss. They were housed individually in 24-in. x 24-in. X 36-in. stainless steel cages with water continuously available. Ss were given pelleted dog food for 1 hr. each day for 3 days prior to the beginning of maze trials. The apparatus was a cross-maze used as a T-maze in this experiment. The start box and goal boxes were 12 in. X 12 in. x 30 in. (inside dimensions) and the choice point connecting these was 12 in. X 12 in. X 12 in. The maze had black plastic walls, a clear plastic top, and a grid floor. The guillotine doors of the maze were electronically controlled from a monitor in a room adjacent to the maze room. The maze room was 8 ft. x 10 fc. x 8 ft. and was dark during the running of Ss, with the exception of light from photocells located 6 in. from the end of each arm of the maze. A 5-in. X 4-in. X 3-in. glass dish was placed in each goal box near the choice point and a 5-in. X 4-in. glass plate was placed at the end of each goal box away from the choice point. The olfactory stimulus was two drops of oil of wintergreen in one of the dishes and one drop in the corresponding plate. The glassware was washed out and a fresh stimulus applied at the beginning of each day's trials. A trial required placing the glassware with the olfactory stimulus randomly in one or the other goal box and allowing S to run from the start box into one of the goal boxes where a photocell switch was activated closing the guillotine doors. On the glass plate in the goal box containing the olfactory stimulus was the reinforcement, an M&M candy which is palatable and easy to use.

Septal lesions enhance shock avoidance behavior in the rat

King reported that rats with septal lesions showed quicker learning of a conditioned avoidance response than did control subjects. Our study extends these findings to Long-Evans hooded rats and a training procedure using a fixed intertrial interval of 1 min, a guillotine door separating the two compartments of the avoidance apparatus and a light instead of a buzzer as the CS. Also, subjects were trained 70 days after the septal lesions had been made. Because eight of the fifteen rats with septal lesions did not demonstrate the hyperemotionality syndrome at the time of behavioral testing but performed the conditioned avoidance response significantly better than the controls, it is concluded that the septal syndrome as here measured is not a necessary condition for the improved learning. These results can be accounted for if one assumes that septal lesions weaken fear-elicited, unconditioned responses, which usually compete with the instrumental avoidance response.

Influence of Conditions at the Time of Reinforcement upon the Strength of a Secondary Reinforcement Effect

Animals were trained to run through a guillotine door into an adjacent compartment for water reinforcement. They were then given access to the compartment as a consequence of bar-pressing, but no water. At the time of testing for bar-pressing various changes were made in the type of response required. For other groups of animals variations were made in the relative sizes of the two compartments during both training and testing. It was found that “getting into the starting box” was as reinforcing as “getting out of the starting box,” that learning in the testing situation did not occur unless previous water reinforcement had been given in one of the compartments, and that changes in the type of response required at the time of testing did not diminish the learning effect.

Secondary Reinforcement in New Learning-Situations

The principle of secondary reinforcoment is based upon two empirical generalizations: first, that resistance to extinction is increased by stimuli which have been previously associated with primary reinforcement; and, secondly, that such stimuli may serve as reinforcing agents in a new learning-situation. The validity of the Erst generalization has recently been challenged by the Ending that stimuli associated with non-reinforcement may, under certain conditions, produce greater resistance to extinction than do stimuli associated with reinforcement.l 'rhe present study presents an analogous challenge to the second generalization. A learning-situation is described in which stimuli associated with non-reinforcement were more effective in producing and maintaining a learned response than stimuli associated with primary reinforcement. Sgbjects. Twenty male albino rats of the Wistar strain were tested in this study. They ranged in age from 120-160 days during the period in which the data were collected. ApparatS. The apparatus used was an elevated T-maze with detachable arms. Removal of either arm formed an elevated L-shaped runway. The threc sections (approach-stem and two arms) were painted mid-gray and were 18 in. high, 2 in. wide, and 24 in. long. Two separate goal-boxes, 13 X 13 X 8 in., were also used. Except for the front panels, the exteriors of these boxes were identical. Their sides and backs were painted gray to match the runway, and their tops were covered with sheets of opal glass. One of the boxes had a white interior, a white front panel, and a floor covered with hardware-cloth. In addition, the white box had a guillotine door (also white) in the front panel. The other box had a black interior, a black front panel, and a smooth floor. Throughout all portions of the experiment, the goal-boxes were so situated at the end of the maze that the entrance always faced away from the starting point. The black and white panels were, therefore, not visible at the turning point. trdining. In the training stage, the Ss were given 20 spaced trials (15-min. minimal

A Multipurpose Discrimination Apparatus for General Laboratory Use

The Multipurpose Discrimination Apparatus (MDA) is essentially a modification of the Wisconsin General Test Apparatus (WGTA) designed primarily for use with human adults and children. With only slight additional changes it should be suitable for work with primate Ss as well. The MDA is more compact and portable than the WGTA, is easier to use, and probably less expensive to construct. The apparatus has been in use at LSU in the experimental laboratory course during which time it has proved practical and versatile for student and professional investigations. From the schematic drawing in Fig. 1 it may be seen that the stimulus tray of the WGTA has been converted into a drawer arrangement with a sliding cover thereby entirely eliminating the use of one guillotine door. With the