Single Alternation Schedule Research Articles

Effects of early postnatal gonadal steroids on acquisition and extinction of a single alternation response in discrete-trials lever pressing

The present report studies the effect of sex on the acquisition and extinction of a single alternation schedule of reinforced (R) and nonreinforced (N) trials in a skinner box. In addition to the investigation of the basic sex differences in Experiment 1, the effects of early gonadal steroids treatment and postpubertal gonadectomy of male and female rats were examined in Experiments 2 and 3, respectively. Both acquisition and extinction performances were evaluated by means of latency. In Experiment 1, males showed higher latencies on N trials and extinguished faster than female rats. In Experiment 2, female androgenization and male orchidectomy on day one after birth reversed the direction of the sex differences found in the previous experiment. However, postpubertal gonadectomy (Experiment 3) does not affect the performance of male and female rats.

Partial reinforcement delayed extinction effect after regularly alternating reward training

When extinction is delayed very long, the superior resistance to extinction of the random schedule group relative to the alternating schedule group disappears (partial reinforcement delayed extinction effect, PRDE). Two experiments assessed the effects of reinforcement/nonreinforcement on Trial 1 on the PRDE. Following extended partial reinforcement acquisition training in a runway, rats received extinction training after a short (1-day) or long (23-day) retention interval. The schedules used in Experiment 1 were: a single-alternation (SA) schedule beginning each day with a rewarded (r) trial, for Group r-SA; an SA schedule beginning with a nonrewarded (n) trial, for Group n-SA; and a random (Rd) schedule, for Group Rd. The schedules and group names used in Experiment 2 were r-SA, Rd, and r-Rd. The results were that (1) rats given r-SA schedules yielded considerable resistance under delayed extinction, (2) those given Rd and r-Rd schedules showed a decline in resistance to extinction over a long retention interval, (3) those given the n-SA schedule showed relatively low resistance at both retention intervals, although retention deficit was not greater than in the case of the Rd schedule, and thus, (4) the PRDE was found in both experiments, although only weakly in Experiment 1. The results indicated that a regularly alternating reward pattern was a more important determinant than was type of reward on Trial 1 for the PRDE. The PRDE due to differential retention deficits among schedules is discussed on the basis of dual-process associative sequential mechanisms and cognitive rule-encoding mechanisms.

Hippocampal unit response during temporal single alternation of classical conditioning with rewarding brain stimulation in the rat

To evaluate hippocampal function on working memory, an experiment of rewarding classical conditioning with a temporal single-alternation (SA) paradigm was conducted. White rats that showed positive self-stimulation to the lateral hypothalamus were trained on an SA schedule with 60-sec intervals, in which reinforced trials (R; CS-US) were regularly alternated with non-reinforced trials (N; CS alone). Unit activity from the hippocampus and the animals’ movements were recorded during the pairing of auditory CS and lateral hypothalamic stimulation (US). When the experimental schedule was shifted to SA from pseudoconditioning, the hippocampal unit activity increased in the CS periods on both R and N trials in the absence of behavioral response alternation. During SA training, hippocampal unit activity in the CS period significantly increased on R trials relative to N trials, when a differential behavioral response also appeared. No detectable differences in the hippocampal unit background pre-CS levels were found between R and N trials. The results are discussed in terms of the interaction between working memory and reference memory in the hippocampal function.

Transfer of single- and double-alternation patterning as a function of odor cues

Two squads of rats were initially given single-alternation (SA) training and subsequently shifted to a double-alternation (DA) schedule. Two other squads were initially trained under a DA schedule and shifted to a SA schedule. The results showed that there was no persistence of behavior learned under one schedule to the new schedule. (Performance conformed appropriately and virtually immediately to the new schedule.) These results suggest that contemporary odor conditions may be very salient cues in situations involving transferring behavior from one schedule of reinforcement to another.

The effect of temporal single alternation on learned increases in hippocampal unit activity in classical conditioning of the rabbit nictitating membrane response

Rabbits were trained with a temporal single-alternation schedule in which reinforced (CS-US) trials were regularly alternated with nonreinforced (CS-alone) trials. Thus, CS-US trials were invariably preceded by CS-alone trials and CS-alone trials were invariably preceded by CS-US trials. In agreement with previous research, there was no evidence of behavioral discrimination; that is, conditioned nictitating membrane responses were no larger on CS-US trials than on CS-alone trials. In contrast, hippocampal multiple unit activity showed (1) greater conditioned increases on CS-US trials and (2) lowered pre-CS levels prior to CS-US trials. In a second experiment, CS-alone trials were replaced by “dummy” trials on which no stimuli were presented. There was no difference in pre-“CS” activity between CS-US and “dummy” trials, indicating that the effect shown in the first experiment was not produced by unlearned effects of US presentation. These results support the notion of an important role for the hippocampus in “working” memory.

Sodium Amylobarbitone and Responses to Nonreward*

Three experiments are reported testing two alternative hypotheses concerning the behavioural effects of sodium amylobarbitone (SA): (1) that it blocks the after-effect of nonreward; (2) that it blocks conditioned frustration, elicited by stimuli associated with nonreward. In support of (2) Experiment I showed that SA given in acquisition abolished the partial reinforcement extinction effect (PREE) when rats were run at one trial a day in an alley for food reward on a continuous (CRF) or partial (PRF) reinforcement schedule. Experiment II showed that, in the goal section, the effect of the drug on the PREE was due to its presence during acquisition and was not due to state dependency; but the effect of the drug in the start section was consistent with state dependency of the PREE. In Experiment III, in opposition to (1) and again in support of (2), SA given to rats trained to show patterned running for water reward on a single alternation schedule blocked patterning by increasing running speeds on nonreward trials, not by decreasing running speeds on rewarded trials.

Acquisition and extinction effects of partial reinforcement under conditions of thirst motivation

Two experiments investigated the generality of partial reinforcement effects across motivational conditions by examining the effects of partial water reinforcement in thirst motivated rats. In Experiment I, patterned responding was observed for subjects that received a single alternation schedule of reinforced (R) and nonreinforced (N) trials, i.e., they learned to run slower on N trials than on R trials. Subjects that received a nonalternating partial reinforcement schedule (PRF) did not exhibit patterned responding. In Experiment II, subjects that received PRF were more resistant to extinction than subjects that received continuous reinforcement during acquisition. The data from both experiments suggests a high degree of similarity in the effects of partial reinforcement regardless of appetitive motivational condition.

Effects of hippocampal x-irradiation-produced granule-cell agenesis on instrumental runway performance in rats

Rats in which x-irradiation during early postnatal life had interfered with the acquisition of dentate granule cells ran faster than controls during extinction of a runway response acquired under a consistent food reward schedule. A training schedule of randomly rewarded and nonrewarded trials increased running speeds to an equal extent in x-irradiated and control groups during extinction. The second and third experiments showed that unlike a reported total inability of hippocampal lesioned rats to pattern their running responses appropriate to a single alternation schedule of reward and nonreward, x-irradiated rats, while impaired in acquiring response alternation, did pattern and had persistent deficits compared to controls only when the task was made very simple by reducing the number of daily trials to two. The results are discussed in terms of an hypothesized reduction in the aversiveness of nonreward and a consequent reduction in the growth of inhibition in x-irradiated rats.

Pattern Discrimination Based on Intermittent Punishment

2 groups of 10 rats were trained in a runway with consistent reward and intermittent punishment. One group received the shocks according to a single alternation schedule and the second group was trained with an irregular schedule. The animals in the alternating schedule, but not the irregular schedule, learned a pattern discrimination suggesting that punishment produces a unique stimulus aftereffect.

Enhancement of rats’ single-alternation performance by high food deprivation

Rats were trained in a straight alley with a single-alternation schedule of reward and nonreward under either high (11 g/day) or low (20 g/day) food deprivation. Ss under high deprivation were superior in patterning performance to those under low deprivation, the form of this result differing over segments of the alley. In the goal segment, the high-deprivation animali’ ran faster on rewarded trials than the low-deprivation animals, while in the start segment, the high-deprivation animals ran more slowly on nonrewarded trials than the low-deprivation animals. It was suggested that increasing food deprivation increases the reward value of food and the aversiveness of nonreward

Classical appetitive conditioning of the rabbit's (Oryctolagus cuniculus) jaw-movement response with a single-alternation schedule.

Classical appetitive conditioning of the rabbit's (Oryctolagus cuniculus) jaw-movement response with a single-alternation schedule.

Frustration effect after development of patterned responding to single-alternation reinforcement

Using a 20-min ITI, one group received single-alternation partial reinforcement in the first alley of a double-runway apparatus. A second group also ran to a single-alternation schedule in Alley 1, but did not run in Alley 2. Results indicated that single vs double alley running did not affect the rate of development, or the terminal strength, of patterned responding. A substantial decrease in the magnitude of the frustration effect occurred in the second alley as patterning developed in the first.

Classical appetitive conditioning of the rabbit's jaw movement response under partial and continuous reinforcement schedules

Continuous, random 50%, and single alternation (SA) schedules of reinforcement were employed in an investigation of classical appetitive conditioning of the jaw movement response in the rabbit. It was found that: ( a) random 50% and SA reinforcement schedules led to lower levels of acquisition performance than continuous reinforcement; ( b) evidence of response patterning to the SA schedule appeared only within and not across acquisition sessions; and ( c) extinction performance decreased at a faster rate under continuous than under the partial reinforcement schedules. The findings are discussed with regard to Spence's (1960) account of partial reinforcement effects in instrumental reward conditioning, and Capaldi's (1966) sequential hypothesis of partial reinforcement extinction effects.

Reward schedule effects at a relatively long intertrial interval

Employing a minimum 20 min intertrial interval (ITI) and extended acquisition training, it was found that a single alternation schedule of partial reward produced less resistance to extinction than an irregular schedule. These results support the sequential hypothesis and appear incompatible with the frustration hypothesis.

Performance under a single alternation schedule of reinforcement at 24-hour intertrial intervals

Rats were trained on a single-alternation schedule of partial reinforcement for 192 days, one trial per day. There was no evidence of pattern running, i. e., faster running on rewarded as compared to nonrewarded trials, by the end of training. It is concluded that the results of a recent experiment claiming to show pattern running at a 24-hour intertriai interval are due to procedural