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PubMed2004

Effects of age and awareness on eyeblink conditional discrimination learning.

The present study aimed to assess the effects of aging and awareness on conditional discrimination learning within an eyeblink conditioning procedure by using a consecutive age-groups design (20-35 years, 36-50 years, 51-65 years, 66-80 years). Increasing age was associated with a decline in overall eyeblink conditioned response (CR) frequency and a deficit in conditional discrimination learning in the 2 older groups. Awareness of stimulus contingencies affected discrimination performance but not overall CR rates in younger subjects. Older subjects did not achieve eyeblink conditional discrimination learning, regardless of awareness. Discrimination performance correlated with measures of declarative memory. The pattern of results is discussed with respect to the involvement of hippocampal-cerebellar interactions and awareness in the mediation of age-related conditioning changes.

Adult↗
PubMed1999

Sociality and social learning in two species of corvids: the pinyon jay (Gymnorhinus cyanocephalus) and the Clark's nutcracker (Nucifraga columbiana).

The hypothesis that social learning is an adaptive specialization for social living predicts that social species should learn better socially than they do individually, but that nonsocial species should not exhibit a similar enhancement of performance under social learning conditions. The authors compared individual and social learning abilities in 2 corvid species: the highly social pinyon jay (Gymnorhinus cyanocephalus) and the less social Clark's nutcracker (Nucifraga columbiana). The birds were tested on 2 different tasks under individual and social learning conditions. Half learned a motor task individually and a discrimination task socially; the other half learned the motor task socially and the discrimination task individually. Pinyon jays learned faster socially than they did individually, but nutcrackers performed equally well under both learning conditions. Results support the hypothesis that social learning is an adaptive specialization for social living in pinyon jays.

Analysis of Variance↗
PubMed1988

Conditional discrimination learning in Aplysia californica.

Two experiments examined whether the relation between a conditioned stimulus (CS) and an unconditioned stimulus (US) might be brought under the control of contextual stimuli in the invertebrate Aplysia californica. Subjects received exposure to 2 different contexts. In both experiments, a tactile CS was paired with a shock US in one of those contexts. In the other context, that tactile CS was either nonreinforced (Experiment 1) or explicitly unpaired with the shock US (Experiment 2). Responding to the CS during a subsequent test was greater in the context in which that CS had been paired with the US compared with the context in which it had been nonreinforced or unpaired. These findings are discussed in terms of theories of conditional discrimination learning.

Animals↗
PubMed2005

The effect of semantic representation on toddlers' word retrieval.

PURPOSE: This study tested the hypothesis that depth of semantic representation influences toddlers' word retrieval. METHOD: Nineteen toddlers participated under 3 word learning conditions in this longitudinal study. Gestures cued attention to object shape (SHP) or function (FNC) in the experimental conditions. No semantic cue was provided under a control condition (CTL). Word learning conditions occurred on each of 3 days. On the 4th day, word retrieval was assessed across 3 levels of scaffolding (uncued picture naming, cued picture naming, picture recognition). Evidence of semantic representation was provided at fast and slow mapping intervals. RESULTS: Less scaffolding was necessary for word retrieval (uncued and cued naming) under experimental conditions than under the CTL condition. However, more SHP than FNC condition targets were retrieved for uncued picture naming. This latter difference may be related to the superior fast mapping of targets under the SHP condition. Toddlers stated object functions (slow mapping) comparably in the experimental conditions, but this was superior to CTL condition performance. CONCLUSIONS: Word retrieval is a continuous behavior that is positively influenced by semantic representation. Semantic knowledge of objects can be enriched by shape or function gestures, thereby improving toddlers' object word productions. Shape cues appear to be more effective for this purpose.

Analysis of Variance↗
PubMed1990

Premotor cortex and conditional motor learning in man.

The role of premotor cortex (PMC) in conditional motor learning tasks in man was investigated. Patients with PMC lesions had to learn to associate 6 different visual, tactile or auditory stimuli with 6 different arm movements which were previously rehearsed (Task A). A comparative task involved an association between the same set of sensory stimuli and 6 spatial locations (Task B). Patients with PMC lesions were only impaired when they had to recall a movement from memory on the basis of a sensory cue (Task A), but not for an association involving spatial location (Task B). This indicates that the PMC plays a role in sensory conditional motor learning.

Adult↗
PubMed1991

Knowledge acquisition and information searching strategies in diagnostic decision making.

The effect of three learning procedures on diagnostic information searching strategies was investigated. Undergraduate students acquired an artificial knowledge domain through either a Taxonomic-, Inductive-, or Case-oriented knowledge acquisition procedure. The use of the competing-hypotheses heuristic as a practical strategy to guide decision making in the face of uncertainty, was compared among the three learning conditions and between each condition and a non-learning control group using the method developed by Kern and Doherty (1982) and Wolf et al. (1985). The small instruction intervention had an effect on the diagnostic nature of subjects' information-searching strategies. Subjects in the Inductive-learning condition exhibited a stronger tendency to seek diagnostically worthless information than the other learning conditions. The outcomes are considered relevant to the nature of expertise in decision making, and to the effect of instruction methodologies on the knowledge representations available to diagnostic classification and decision-making processes.

Diagnosis↗
PubMed1997

Effects of aging on conditional associative learning: process analyses and comparison with focal frontal lesions.

Conditional associative learning (CAL), a measure validated in studies of frontal lesions, was used to evaluate the hypothesis that age-related cognitive decline is related to frontal dysfunction. Older adults and focal frontal participants showed impaired CAL performance, but the deficit was greater in the latter group, where it was specific to participants with dorsolateral prefrontal cortical (DLPFC) lesions. The deficits were attributable to strategic rather than basic associative processes. Error scores described ways in which past information failed to guide behavior, and they were related to lesion location. Congruence between older adults and DLPFC participants on a measure of defective inhibition suggests that age-related decline in inhibitory processes is due to DLPFC dysfunction.

Adolescent↗
PubMed2001

Impaired conditional discrimination learning in schizophrenia.

Learning deficits have repeatedly been found in patients with schizophrenia. Eyelid conditional discrimination learning (ECDL) is a test of discriminative aversive conditioning and places minimal demands on motivation. An ECDL task was used to examine residual and paranoid type individuals with schizophrenia and age- and gender-equivalent healthy controls. In the experiment two differently colored light stimuli were randomly presented. Only one of the stimuli (in reinforced trials) was followed by an aversive airpuff to the cornea, as opposed to unreinforced trials where the stimulus was not followed by an aversive airpuff. Conditioned responses develop to both trial types during the course of the experiment. These conditioned responses consist of reflectory eyelid closures already upon light presentation. The patients showed significantly impaired conditional discrimination learning abilities. There was no significant difference between the results in the two schizophrenia subtypes. Patients failed to increase response frequencies on reinforced trials during the course of the experiment, while controls showed appropriate conditional discrimination ability. Thus the results show an impairment of adequate behavior modification in an aversive conditioning task in individuals with schizophrenia. It is concluded that ECDL might be a trait marker for schizophrenia.

Adult↗
PubMed1980

Conditional discrimination learning: a critique and amplification.

Carter and Werner recently reviewed the literature on conditional discrimination learning by pigeons, which consists of studies of matching-to-sample and oddity-from-sample. They also discussed three models of such learning: the "multiple-rule" model (learning of stimulus-specific relations), the "configuration" model, and the "single-rule" model (concept learning). Although their treatment of the multiple-rule model, which seems most applicable to the pigeon data, is generally excellent, their discussion of the other two models is incomplete and sometimes inaccurate. Potential problems of terminology are discussed in the present paper, as are additional lines of research that deserve consideration by those interested in further work in this area. The issue of response versus stimulus selection (configuration versus compound-cue learning) is discussed in connection with the configuration model. Particular attention is given to Carter and Werner's criticism of the application, in studies with other species, of the learning set procedure in testing for single-rule learning. Some of the important related issues are: the bias for improvement on new problems in a series, the adequacy of a multiple-rule model to explain learning set formation, and evidence in favor of the single-rule model, at least in primates. Consideration of these additional contributions to the study of conditional discrimination learning emphasizes the usefulness of this task in the comparative study of cognitive processes.

Animals↗
PubMed2005

Spatial conditional discrimination learning in developing rats.

The present study established an effective procedure for studying spatial conditional discrimination learning in juvenile rats using a T-maze. Wire mesh located on the floor of the maze as well as a second, identical T-maze apparatus served as conditional cues which signaled whether a left or a right response would be rewarded. In Experiment 1, conditional discrimination was evident on Postnatal Day (PND) 30 when mesh+maze or maze-alone were the conditional cues, but not when mesh-alone was the cue. Experiment 2 confirmed that mesh-alone was sufficiently salient to support learning of a simple (nonconditional) discrimination. Its failure to serve as a conditional cue in Experiment 1 does not reflect its general ineffectiveness as a stimulus. Experiment 3 confirmed that the learning shown in Experiment 1 was indeed conditional in nature by comparing performance on conditional versus nonconditional versions of the task. Experiment 4 showed that PND19 and PND23 pups also were capable of performing the task when maze+mesh was the cue; however, the findings indicate that PND19 subjects do not use a conditional strategy to learn this task. The findings suggest postnatal ontogeny of conditional discrimination learning and underscore the importance of conditional cue salience, and of identifying task strategies, in developmental studies of conditional discrimination learning.

Animals↗
PubMed1992

Differential effect of right and left hemispheric lesions on two memory tasks: free recall of items and recall of spatial location.

The effect of lateralized cerebral damage on free recall of items and recall of spatial location, under intentional and incidental learning conditions, was investigated. Eleven right brain-damaged (RBD) patients, 10 left brain-damaged (LBD) patients, 14 young and 11 elderly normal controls, participated in this study. The overall performance of the control groups was better than that of the patient groups. For all groups, free recall was better under intentional than under incidental learning condition. On recall of spatial location the learning condition had a differential effect on the groups. The RBD group performed better than the LBD group under intentional learning condition, while the reverse was found under incidental learning condition. The young-control group showed an advantage over the elderly-control group under intentional but not under incidental learning condition. The results are discussed in regard to different approaches to the distinction between automatic and effortful memory processes and their lateralization in the cerebral hemispheres.

Adult↗
PubMed2005

Eye movements are functional during face learning.

In a free viewing learning condition, participants were allowed to move their eyes naturally as they learned a set of new faces. In a restricted viewing learning condition, participants remained fixated in a single central location as they learned the new faces. Recognition of the learned faces was then tested following the two learning conditions. Eye movements were recorded during the free viewing learning condition, as well as during recognition. The recognition results showed a clear deficit following the restricted viewing condition, compared with the free viewing condition, demonstrating that eye movements play a functional role during human face learning. Furthermore, the features selected for fixation during recognition were similar following free viewing and restricted viewing learning, suggesting that the eye movements generated during recognition are not simply a recapitulation of those produced during learning.

Eye Movements↗
PubMed2004

Egocentric conditional associative learning: effects of restricted lesions to the hippocampo-mammillo-thalamic pathway.

Rats with lesions of the hippocampus, the mammillary region, the anterior thalamic nuclei, and normal control animals were trained on a conditional associative learning task in which they had to learn to make one of two motor responses (i.e., turn left or right), depending on which one of two visual cues was presented. Damage to the hippocampus severely impaired performance of this task. By contrast, rats with lesions of the mammillary region or the anterior thalamic nuclei were able to acquire the task at a rate comparable to that of the normal animals. These findings demonstrate that hippocampal lesions impair the ability to form arbitrary associations between visual cues and kinesthetic responses (body turns) and, furthermore, suggest that the hippocampus does not rely on input from its major subcortical targets for learning such visual-kinesthetic associations.

Animals↗
PubMed1981

Adult age differences in memory for sex of voice.

Young and older adults (elderly in Experiment 1 and middle-aged in Experiment 2) received successive sentence recall tasks for which one-half of the sentences were read in a male voice and one-half in a female voice. With regard to the sex of voice component, the first task was administered under incidental learning conditions and the second under intentional learning conditions. With regard to sentence content, both tasks were administered under intentional learning conditions. The results indicated that encoding voice information is a cognitively effortful, age sensitive process. For older adults, both elderly and middle-aged, enhanced voice encoding under the intentional condition, relative to the incidental condition, was accompanied by a significant decrement in sentence recall. For young adults, the trade off effect was not large enough to reach statistical significance. The age difference apparently reflects the diminished processing capacity of older adults relative to young adults, with the decrease in capacity having its onset by middle age.

Adolescent↗
PubMed1993

Lateral hyperstriatal lesions disrupt simultaneous but not successive conditional discrimination learning of pigeons (Columba livia).

In 2 experiments we explored the effects of lateral versus medial laminar lesions of the hyperstriatum in pigeons (Columba livia); medical lesions were largely confined to the hyperstriatum accessorium, and lateral lesions to the hyperstriatum dorsale and hyperstriatum ventrale. In Experiment 1, lateral, but not medial, lesions disrupted acquisition of a simultaneous conditional discrimination; both medial and lateral lesions disrupted reversal of the discrimination. The reversal deficits of the medial and lateral groups were quantitatively similar, and both groups showed exaggerated positional responding. In Experiment 2, neither medial nor lateral lesions disrupted acquisition of a successive conditional discrimination. We conclude that lateral hyperstriatal damage does not obtain a general disruption of conditional learning; we speculate that the lateral hyperstriatum may play a critical role in configural learning.

Animals↗
PubMed1985

Conditioning and learning in relation to disease.

Of the two generally recognized processes through which learning occurs--imprinting and conditioning--only the latter with its two paradigms, classical and operant, has both practical and heuristic implications for disease. From the classical conditioning experiments of Pavlov's laboratory over 100 years ago to the later work in operant conditioning by Skinner and others in the past four decades has evolved much of the basis of modern learning theory and its applications to disease in the form of behavior therapy. Variants of behavior therapy have been employed in the treatment of wide variety of medical and psychiatric illnesses. Recent developments in the study of brain function and biochemistry have led to renewed interest in the conditioning paradigm and its value as tool in these areas of research.

Animals↗
PubMed2001

Neurobiology of Pavlovian fear conditioning.

Learning the relationships between aversive events and the environmental stimuli that predict such events is essential to the survival of organisms throughout the animal kingdom. Pavlovian fear conditioning is an exemplar of this form of learning that is exhibited by both rats and humans. Recent years have seen an incredible surge in interest in the neurobiology of fear conditioning. Neural circuits underlying fear conditioning have been mapped, synaptic plasticity in these circuits has been identified, and biochemical and genetic manipulations are beginning to unravel the molecular machinery responsible for the storage of fear memories. These advances represent an important step in understanding the neural substrates of a rapidly acquired and adaptive form of associative learning and memory in mammals.

Amygdala↗