Spatial delayed matching-to-sample performance by rats: Learning, memory, and proactive interference.

Nine Sprague-Dawley rats were trained in a 3-alternative delayed matching-to-sample task in which the samples were rewarded forced choices of 1 arm of a 3-arm starburst maze, and retention was indicated by returning to that arm following a delay or retention interval. If the S made an error on its 1st free choice of a trial, the chosen arm was blocked off, and the S was allowed a 2nd choice between the remaining 2 arms. Ss quickly acquired this task. Exp II showed that choice accuracy was lower with 1-min retention intervals than with immediate tests. In Exp III, there was evidence for 2 separable proactive interference effects. The degree to which prior events influenced responding decreased as the intertrial interval increased. Choice accuracy improved with increasing intertrial interval and declined with increasing retention interval durations. Additionally, choice accuracy was higher when the sample from the previous trial matched the sample from the current trial and lower when they did not match. These results suggest that encoding information about visited spatial locations is a gradual process rather than an all-or-none process in rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Forgetting of visual discriminations by pigeons.

Three experiments examined the forgetting of visual discriminations by 48 Silver King pigeons. The problems consisted of feature discriminations, with dot displays as the discriminative stimuli, and involved a successive go/no-go pecking response. In all 3 experiments, Ss trained to refrain from pecking an S– display resumed pecking at this display after retention intervals. It is argued that these data represent the 1st direct demonstration of forgetting of a discrimination by pigeons. Exp I also showed that the amount of forgetting progressively increased, in a negatively accelerated fashion, over intervals of 1, 10, and 20 days. Also, more S– responses occurred during relearning a reverse discrimination than after relearning a nonreverse discrimination. In Exp II, acquisition was retarded and more forgetting occurred for discriminations that involved more highly similar stimuli. In Exp III, a change in contextual cues between acquisition and retention testing enhanced forgetting when the contextual cues present during original acquisition were conspicuous; when these cues were relatively inconspicuous, a change in context had no effect on forgetting. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial memory in pigeons on a four-arm radial maze.

Examined spatial memory in 6, 8-arm maze experienced pigeons, using a 4-arm radial maze. The maze arms were spaced at 90° intervals, extending radially from a central choice area. Ss were forced into 3 arms, then permitted 2 choices to enter the remaining arm. Five Ss chose accurately (90% correct) with delays of 5 min or less, their choices depended on extramaze cues, and the food in the target arm provided no essential cues. After an incorrect 1st choice, Ss' 2nd choices were more accurate than chance. Data suggest that, while spatial memory has many similar characteristics in rats and pigeons, pigeon spatial memory appears less durable. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquired distinctiveness is controlled by stimulus relevance not correlation with reward.

In 2 experiments, the relationship between the role of a stimulus in signaling trial outcome and the attention paid to it was investigated. In Exp 1, an intradimensional–extradimensional shift effect was shown in pigeons using autoshaping. In Exp 2, pigeons were trained with a biconditional discrimination, using stimulus compounds varying on 3 dimensions (color, orientation, and position), 2 of which were relevant to the solution of the discrimination, and 1 of which was irrelevant. Acquisition of a subsequent biconditional discrimination was more rapid if the same stimulus dimensions were relevant to the solution of both discriminations than if a previously irrelevant discrimination became relevant. These results indicate that the amount of attention paid to a stimulus is determined by its relevance to the solution of a discrimination, and not by its correlation with reward. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing models of delayed sequence discrimination in pigeons: The advance key procedure.

In 2-event delayed sequence discrimination (DSD) training, one arrangement (temporal order) of 2 sample stimuli is the positive sequence and the remaining are the negative sequences for keypecking during a subsequent test stimulus. Three models of the DSD task were tested in 2 experiments with 8 White Carneaux pigeons. In Exp I Ss were allowed to terminate a trial by pecking the "advance key" during the sample stimuli or to let the test stimulus progress to the next trial. In the absence of a peck to the advance key, the trial continued to the completion of the test stimulus. In Exp II, Ss were forced to choose actively between advancing to the next trial and continuing through the current trial. Choice between the advance and continue keys was required with the occurrence of each of the successive sample stimuli and the test stimulus. Although the addition of forced choice resulted in more uniform effects, Ss were able to identify negative sample sequences with the occurrence of the 1st negative sample event in both experiments. Results support the prospective memory model but not the retrospective and hybrid models of temporal sequence recognition in the 2-event DSD task. (French abstract) (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus control of information processing in rat short-term memory.

Male Sprague-Dawley rats were trained initially on a delayed alternation task in which a forced run to 1 arm of a T-maze was followed by a free-choice test run. A correct free-choice response was defined as a turn in the direction opposite that to which S had been forced. Following acquisition, all trials were cued, with a click-rate/illumination-level compound, as to whether a free-choice test would (remember-cued) or would not (forget-cued) occur. In the 1st 2 experiments, forced runs were forget-cued either during (Exp I) or after (Exp II) the forcing, and memory for the direction of the forcing was tested occasionally. In the final 2 experiments, Ss were forced to each run prior to the free-choice test run, and an alternation with respect to the 2nd forcing was defined as correct. On different trials, either the 1st or the 2nd forcing was forget-cued. Each experiment revealed evidence of reduced memory for forget-cued forcings. It is concluded that presentation of a forget cue influences information processing in the rat by affecting processes of either maintenance rehearsal or tagging. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Food searching strategies of rats: Variables affecting the relative strength of stay and shift strategies.

Examined the extent to which the food searching strategies of rats are influenced by training, information about food in an initially visited site, and type of memory required for correct choices. Exp I used a discrete-trial, delayed conditional-discrimination procedure on a T-maze with 32 male Sprague-Dawley rats. Ss entered 1 arm of the maze and were given a choice between that arm (stay strategy) or the other arm (shift strategy). During the initial visit, S either consumed all the food (depletion condition) or only some of it (nondepletion condition). Ss given the shift-depletion task learned most rapidly; those given the stay-depletion task learned most slowly. Depletion increased the rate at which the shift discrimination was learned but decreased the rate at which the stay discrimination was learned. Exp II used a similar procedure with the Maier 3-table maze and 16 male albino rats; the same pattern of results was found. Exp III, conducted with 15 male Sprague-Dawley rats, required each S to learn both a win-stay and a lose-shift contingency and to use associative memory. Early in training, Ss used only a shift strategy but eventually learned the discrimination. Results indicate that the shift-stay balance is influenced by the rat's species-specific predisposition, reinforcement contingencies, amount of food in the initially visited place, and the extent to which recognition memory by itself is sufficient to solve the discrimination. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discrimination of temporal relations by pigeons.

In 4 experiments, pigeons were tested on a duration comparison task involving the successive presentation of two visual stimuli that varied in duration from trial to trial. Following presentation of the durations, 2 choice keys were lit, and reinforcement for choices was based on the temporal relation between durations of the pair. In Exp 1, the range of durations was varied over conditions. Responding changed as an orderly function of the ratio of the 2 durations. There was a decrease in discrimination accuracy as average duration increased over conditions. In Exp 2, Ss were transferred from a task involving spatially differentiated choices to one involving hue-differentiated choices. Performance was similar to that of Exp 1. In Exp 3, Ss were exposed to a single duration range that included many durations from the 4 ranges of Exp 1. Discrimination accuracy was comparable on 3 problem duration categories within this range and declined slightly for problems in the 4th and longest category. Manipulation of absolute reinforcement rate in Exp 4 resulted in no change in discrimination accuracy, suggesting that the decline in accuracy over conditions of Exp 1 could not be attributed to decreases in reinforcement rate that accompanied lengthier durations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequential effects in pigeon delayed matching-to-sample performance.

Five pigeons were tested in a 3-alternative delayed matching-to-sample task in which 2nd choices were permitted following 1st-choice errors. Sequences of responses both within and between trials were examined in 3 experiments. In Exp I, the sample information contained in 1st-choice errors was not sufficient to account for the observed pattern of 2nd choices. This implies that 2nd choices following 1st-choice errors are based on a 2nd examination of the contents of working memory. Proactive interference was found in Exp II in the form of a dependency, beyond that expected on the basis of trial-independent response bias, of 1st-choices from 1 trial on the 1st-choice emitted on the previous trial. Samples from the previous trial did not exert a significant influence on later trials. The magnitude of the intertrial association (Exp III) did not depend on the duration of the intertrial interval. In contrast, longer intertrial intervals and longer sample durations facilitated choice accuracy by strengthening the association between current samples and choices. Results are incompatible with a trace-decay and completion model; they suggest that multiple influences act simultaneously and independently to control delayed matching-to-sample responding. These influences include memory for the choice occurring on the previous trial, memory for the sample, and general effects of trial spacing. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial memory in pigeons on the radial maze.

A series of 7 experiments with 10 pigeons showed, contrary to recent suggestions that pigeons show little or no spatial memory on the radial maze, highly accurate performance by Ss on an 8-arm radial maze. In Exp I, Ss were trained on successive phases that raised the number of alleys to be remembered from 1 to 4. In Exp II, Ss were allowed to search the maze for food with all 8 arms open. Measures of spatial memory showed that Ss performed at a level equivalent to that found with rats in previous research by A. B. Bond et al (see record 1982-25052-001). In Exp III, testing with massed trials revealed proactive interference. Ss were able to form reference memory for subsets of baited and unbaited alleys in Exp VI. In Exp VII, Ss learned about quantities of food associated with 4 different alleys and ordered their alley choices from the largest to the smallest reward. Contrary to the previous findings with rats, Ss in Exp IV showed forgetting over retention intervals of 0–360 sec between forced and free choices. It is concluded that spatial memory in pigeons generally shows the same properties as that in rats. (49 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Early and late acquisition of discriminative neuronal activity during differential conditioning in rabbits: Specificity within the laminae of cingulate cortex and the anteroventral thalamus.

Recorded multiple-unit activity of the circulate cortex and the anteroventral (AV) nucleus of the thalamus during discriminative conditioning of an avoidance response (locomotion) in 50 New Zealand White rabbits. Results indicate a greater unit response in cingulate cortex to the positive conditional stimulus (CS+; a tone paired with a footshock UCS) relative to the negative conditional stimulus (CS–; a tone randomly interspersed with the positive stimuli but never paired with the UCS). The majority of neuronal records obtained from the deep laminae of cingulate cortex manifested 1st neuronal discrimination in the session of 1st exposure to conditioning. However, the majority of neuronal records of the superficial laminae showed 1st discrimination at a late stage of training, during the session in which the criterion of behavioral discrimination was met. The late developing discriminative activity of the superficial laminae was coincident with the late developing discriminative activity of the AV thalamus. Once acquired, neuronal discrimination in cortex persisted throughout 600 msec after CS onset, and during 6 sessions of training of overtraining. Analysis of individual neuronal records suggested that the persistence during overtraining resulted from replacement of early fading neuronal discriminations by late neuronal discriminations. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance of goldfish (Carassius auratus) in patterned sequences of rewarded and nonrewarded trials.

Studied the performance of 40 goldfish in 4 experiments with patterned sequences of reward (R) and nonreward (N) for responses to a given stimulus (S3). Trials with 2 other, readily discriminable stimuli, in which response to one was always rewarded and response to the 2nd never rewarded, were interpolated in such a way that the outcome of any S3 trial could not be predicted from the events of the immediately preceding trial. The main purpose was to look for control of response to S3 based on memory of N like that found in previous work with pigeons. In Exps I and II, blocks of R and N trials with S3 were programmed, R trials in the 1st half of each session and N in the last half, or N trials in the 1st half and R in the last half. In Exp III, successive acquisition and extinction of response to S3 was studied, with the N-to-R, and R-to-N transitions either within sessions or between sessions. In Exp IV, the effects of partial and consistent reinforcement on extinction of response to S3 were compared. Results are similar in important respects to those for pigeons, as described by P. A. Couvillon et al (see record 1981-07158-001), but different in their failure to demonstrate control of performance by memory of N. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Meaning and modality: Influences of context, semantic memory organization, and perceptual predictability on picture processing.

Using event-related potentials (ERPs), the authors investigated the influences of sentence context, semantic memory organization, and perceptual predictability on picture processing. Participants read pairs of highly or weakly constraining sentences that ended with (a) the expected item, (b) an unexpected item from the expected semantic category, or (c) an unexpected item from an unexpected category. Pictures were unfamiliar in Exp 1 but preexposed in Exp 2. ERPs to pictures reflected both contextual fit and memory organization, as do ERPs to words in the same contexts (K. D. Federmeier and M. Kutas, see record 1999-15076-002). However, different response patterns were observed to pictures than to words. Some of these arose from perceptual predictability differences, whereas others seem to reflect true modality-based differences in semantic feature activation. Although words and pictures may share semantic memory, the authors' results show that semantic processing is not amodal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of posterior septal lesions on dispositional and representational memory.

[Correction Notice: An erratum for this article was reported in Vol 101(1) of Behavioral Neuroscience (see record 2008-10683-001). A phrase was erroneously deleted from the text. In the seventh paragraph on p. 713, the second sentence should read as follows: Early in training individual differences were great, but by the end of adaptation training, individual differences were quite small and all rats responded at close to asymptotic speeds.] A distinction between 2 classes of memory has been made in terms of the sensory availability of cues at the time of making discriminations that are influenced by past experience. Three tasks objectively defining this distinction were learned in a T-maze by 36 male Long-Evans rats in 3 groups: (a) a delayed non-matching-to-sample (DNMTS) that depended on representational memory; (b) a simple sensory discrimination (SD) that depended on dispositional memory; and (c) a more difficult discrimination that also depended on dispositional memory, called the simultaneous conditional discrimination (SCD). The DNMTS and SD tasks were acquired quickly; the SCD task took many more trials. Posterior septal lesions impaired DNMTS performance but had no effect on retention of tasks that depended on dispositional memory. Results indicate that dispositional and representational memory systems have at least partially distinct anatomical substrates in the brain and that it is the representational and not the conditional aspects of the DNMTS task that are impaired by the septal lesions. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retroactive interference effects of surprising reward omission on serial spatial memory.

Reward omission was used to produce retroactive interference in a serial delayed-alternation task. Rats were given forced choices in 3 T mazes presented in succession followed by free choices in which the alternate arm in each maze was rewarded. Nonreward during the delay between forced- and free-choice runs produced a decrement in performance (i.e., retroactive interference) in comparison to reward during the delay. Interference in retention of the first maze in a list occurred when the second maze contained surprising reward or omission (i.e., an outcome contrary to previous training in that maze) in comparison to expected reward or omission. In addition to producing retroactive interference, omission sometimes increased alternation in the maze in which it occurred. These results support a differential rehearsal hypothesis of spatial memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frequency-range discriminations and absolute pitch in black-capped chickadees (Poecile atricapillus), mountain chickadees (Poecile gambeli), and zebra finches (Taeniopygia guttata).

The acoustic frequency ranges in birdsongs provide important absolute pitch cues for the recognition of conspecifics. Black-capped chickadees (Poecile atricapillus), mountain chickadees (Poecile gambeli), and zebra finches (Taeniopygia guttata) were trained to sort tones contiguous in frequency into 8 ranges on the basis of associations between response to the tones in each range and reward. All 3 species acquired accurate frequency-range discriminations, but zebra finches acquired the discrimination in fewer trials and to a higher standard than black-capped or mountain chickadees, which did not differ appreciably in the discrimination. Chickadees' relatively poorer accuracy was traced to poorer discrimination of tones in the higher frequency ranges. During transfer tests, the discrimination generalized to novel tones when the training tones were included, but not when they were omitted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Differential effects of posterior septal lesions on dispositional and representational memory": Correction to Thomas and Gash (1986).

Reports an error in "Differential effects of posterior septal lesions on dispositional and representational memory" by Garth J. Thomas and Don M. Gash (Behavioral Neuroscience, 1986[Oct], Vol 100[5], 712-719). A phrase was erroneously deleted from the text. In the seventh paragraph on p. 713, the second sentence should read as follows: Early in training individual differences were great, but by the end of adaptation training, individual differences were quite small and all rats responded at close to asymptotic speeds. (The following abstract of the original article appeared in record 1987-06585-001.) A distinction between 2 classes of memory has been made in terms of the sensory availability of cues at the time of making discriminations that are influenced by past experience. Three tasks objectively defining this distinction were learned in a T-maze by 36 male Long-Evans rats in 3 groups: (a) a delayed non-matching-to-sample (DNMTS) that depended on representational memory; (b) a simple sensory discrimination (SD) that depended on dispositional memory; and (c) a more difficult discrimination that also depended on dispositional memory, called the simultaneous conditional discrimination (SCD). The DNMTS and SD tasks were acquired quickly; the SCD task took many more trials. Posterior septal lesions impaired DNMTS performance but had no effect on retention of tasks that depended on dispositional memory. Results indicate that dispositional and representational memory systems have at least partially distinct anatomical substrates in the brain and that it is the representational and not the conditional aspects of the DNMTS task that are impaired by the septal lesions. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of chronic alcohol consumption or Diazepam administration on item recognition and temporal ordering in a spatial working memory task in mice

This study was aimed at determining the effects of either Diazepam administration or chronic alcohol consumption (CAC) on spatial memory measured by concurrent discriminations in an eight arm radial maze using mice as subjects. Two different protocols involving a non-matching rule were used to evaluate either temporal order (recurrent items) or item recognition (non-recurrent items). Results showed that both Diazepam administration and CAC produced a memory deficit which was primarily observed in the temporal task, whereas item recognition was spared. These data show that Diazepam and CAC produced similar memory impairments. Thus, our study stressed the potential importance of the GABA/BDZ dysfunction in the production of organic amnesia of alcoholic origin. The overall analysis of the data suggests that both CAC and Diazepam injections would impair forms of memory sustained by automatic or incidental learning.     

A temporal distinctiveness theory of recency and modality effects.

Conducted 4 experiments with 40 undergraduates and 60 Ss drawn from a university community to confirm the qualitative and quantitative predictions of a temporal distinctiveness theory of contextually cued retrieval from memory as applied to recency and modality (auditory vs visual) effects on the recall of a list of word pairs. Results of Exp I demonstrated that increasing the length of the temporal isolation of the last word pair aurally presented increased recall of the item; increase in recall of the last item was smaller or absent for the visual presentation of the pairs. Exp II indicated that as the number of word pairs isolated at the end of the list increased, the size of the modality effect decreased. Temporal distinctiveness between the 1st and 2nd pairs in Exp III revealed auditory superiority in recall of the 1st pair, an effect that was eliminated in Exp IV when isolated interval occurred between the 3rd and 4th presentation of a 6-item word pair list. A mathematical model of the quantitative predictions of the theory is appended. (46 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)