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At least 55 records · Page 3Linked to original sources
PubMed2003

Lubeluzole and conditioned learning after cerebral ischemia.

Lubeluzole [S-4-(2-benzothiazolylmethylamino)-alpha-((3,4-difluorophenoxy)methyl)-1-piperidineethanol] reduces the severity of cerebral injury in animal models of brain ischemia. Its beneficial effects may include decreased concentration of extracellular glutamate, blockade of sodium and calcium channels, and attenuation of nitric oxide-mediated neuronal death. Previous studies have shown that global cerebral ischemia in rabbits impaired the subsequent acquisition of a trace-conditioned eyeblink reflex. Here, we examined the effect of preischemic treatment with lubeluzole on the acquisition of a trace-conditioned eyeblink response after 6.5 min of global cerebral ischemia. Three groups of rabbits underwent cerebral ischemia: one group underwent ischemia alone (I) and two groups underwent ischemia and also received lubeluzole (L(1), 1.25 mg/kg, and L(2), 2.5 mg/kg). All animals were subsequently trained using classical trace conditioning. Each training session consisted of the presentation of the conditioned stimulus (an 85-dB, 6-kHz auditory tone lasting for 100 ms) followed by a trace interval (a period of 300 ms during which no external stimulus was delivered) followed finally by the delivery of the unconditioned stimulus (a 150-ms puff of air directed at the cornea). We found that animals receiving preischemic administration of 1.25 mg/kg of lubeluzole demonstrated a significantly improved acquisition of the trace-conditioned reflex as compared to animals that did not receive lubeluzole. This finding demonstrates improved long-term neurobehavioral outcome with preischemic administration of 1.25 mg/kg of lubeluzole.

Animals↗
PubMed1992

Field dependence/independence and learning condition: an exploratory study of style vs ability.

Recent reviews have concluded that field-independent individuals typically show learning equal or superior to that of field-dependent individuals. However, many studies supporting these conclusions have not capitalized fully on the stylistic strengths of field-dependent learners. Among 35 field-independent and 42 field-dependent undergraduates, when grade-point average was controlled, no significant differences were found in scores on an examination following an audiotaped lecture. However, field-dependent learners significantly outperformed their field-independent peers on follow-up quizzes when material was presented interactively, using examples that required social sensitivity for full appreciation. These results are discussed as supporting the importance of further study of the stylistic aspects of field dependence/independence and the narrowness of conceptualizations of individual differences when teaching.

Achievement↗
PubMed2005

The relationship between initial errorless learning conditions and subsequent performance.

This experiment explores a suggestion by [Maxwell, J.P., Masters, R.S.W., Kerr, E., Weedon, E. (2001). The implicit benefit of learning without errors. Quarterly Journal of Experimental Psychology A 54, 1049-1068] that an initial bout of implicit motor learning confers beneficial performance characteristics, such as robustness under secondary task loading, despite subsequent explicit learning. Participants acquired a complex motor skill (golf putting) over 400 trials. The environment was constrained early in learning to minimize performance error. It was predicted that in the absence of explicit instruction, reducing error would prevent hypothesis testing strategies and the concomitant accrual of declarative (explicit) knowledge, thereby reducing dependence on working memory resources. The effect of an additional cognitive task on putting performance was used to assess reliance on working memory. Putting performance of participants in the Implicit-Explicit condition was unaffected by the additional cognitive load, whereas the performance of Explicit participants deteriorated. The relationship between error correction and episodic verbal reports suggested that the explicit group were involved in more hypothesis testing behaviours than the Implicit-Explicit group early in learning. It was concluded that a constrained, uninstructed, environment early in learning, results in procedurally based motor output unencumbered by disadvantages associated with working memory control.

Adult↗
PubMedDate not supplied

Rapid associative learning: conditioned bradycardia and its central nervous system substrates.

It has become clear from the study of different response systems during classical conditioning that some responses are acquired quite rapidly and others show a much slower rate of acquisition. The most often studied rapidly acquired responses have been classically conditioned autonomic changes (e.g., heart rate); the slowly acquired responses most often studied are skeletal responses, such as the eyeblink or leg flexion response. Although there are various other differences between rapidly acquired and slowly acquired responses, we have suggested that the most important difference is the possibility that they represent different stages of the learning process. In the present review I describe research in our laboratory that has focused on conditioned bradycardia as a model system of a rapidly acquired associative system and contrast it with the more slowly acquired Pavlovian conditioned eyeblink response. I also describe the generality of conditioned bradycardia and discuss the differential role of subdivisions of the prefrontal cortex as a substrate for mediating this response. Finally, I briefly discuss the other brain areas involved in conditioned bradycardia, and its functional significance as it relates to the learning process.

Animals↗
PubMed2005

Sex, stress, and fear: individual differences in conditioned learning.

It has long been recognized that humans vary in their conditionability, yet the factors that contribute to individual variation in emotional learning remain to be delineated. The goal of the present study was to investigate the relationship among sex, stress hormones, and fear conditioning in humans. Forty-five healthy adults (22 females) underwent differential delay conditioning, using fear-relevant conditioned stimuli and a shock unconditioned stimulus. Salivary cortisol samples were taken at baseline and after acquisition training and a 24-h-delayed retention test. The results showed that acquisition of conditioning significantly correlated with postacquisition cortisol levels in males, but not in females. This sex-specific relationship was found despite similar overall levels of conditioning, unconditioned responding, and cortisol. There was no effect of postacquisition cortisol on consolidation of fear learning in either sex. These findings have implications for the understanding of individual differences in fear acquisition and risk factors for the development of affective disorders.

Analysis of Variance↗
PubMed1990

Nonspatial conditional learning impaired in patients with unilateral frontal but not unilateral temporal lobe excisions.

The present study examined the effect of unilateral frontal- or temporal-lobe excisions on the acquisition of a conditional task requiring that the subjects respond to each one of six different coloured stimuli by selecting, from a set of six abstract designs, the correct design for each stimulus. Patients with excisions from the left or right frontal cortex were impaired in learning this task, whereas patients with left or right temporal-lobe excisions, with or without radical involvement of the hippocampal region, were not impaired. These findings demonstrate that the major role played by the frontal cortex in the acquisition of conditional responses is a general one and not restricted to situations involving different movements.

Adolescent↗
PubMed1975

Conditioned learning in young rats born of drug-addicted parents and raised on addictive drugs.

Ratlings born of six drug-addicted and a control group of parent rats were raised under the influence of the same drugs administered in drinking water. They were trained in a conditioned avoidance paradigm (CAR) from the 7th week when the drugs were withdrawn except in two subgroups of flurazepam and morphine. The growth rate was not appreciably impaired except for temporary slowness in morphine and alcohol-raised rats; it was faster in phenobarbitone and meprobamate-raised rats. The CAR-acquisition rates of the treatment groups were quite close and parallel to that of the controls except for the morphine, meprobamate, medazepam and the two drug-trained subgroups; whereas, the rats raised on low-dose morphine showed a faster than control acquisition rate. No evidence of state-dependent learning was obtained from this study.

Animals↗
PubMed2004

Unconscious learning. Conditioning to subliminal visual stimuli.

The role of consciousness in Pavlovian conditioning was examined in two experiments in which visually masked neutral words were used as the conditioned stimuli (CS) and an electric shock as the unconditioned stimulus (US). The inter-stimulus interval (ISI) was established individually. A detection threshold was used in Experiment 1 and an identification threshold in Experiment 2. The primary dependent variable was the skin conductance response (SCR). Results showed that the conditioned response (CR) was acquired by 58% of participants who perceived stimuli above the identification threshold, 50% of participants who perceived stimuli below the detection threshold, and 11% of participants who perceived stimuli below the identification threshold, but above the detection threshold. These results suggest that consciousness of the CS-US contingency is not a necessary condition for acquiring a CR of the autonomous nervous system (ANS).

Adolescent↗
PubMed1995

Conditional learning and memory impairments following neurotoxic lesion of the CA1 field of the hippocampus.

Monkeys with bilateral lesions of the CA1 field of the hippocampus produced by the injection of neurotoxin diagonally along the length of the hippocampus were found to have a severe impairment on the retention of a conditional task learnt prior to surgery and on the new acquisition of several types of this task. They were equally impaired on conditional tasks that required a spatial response or an object choice in response to either visual or spatial cues. They were not impaired on simple visual discrimination tasks, simple spatial discrimination tasks or reversal learning of these tasks. This patterns of impairment resembles that seen in the same species with neurotoxic lesions within the vertical limb of the diagonal band of Broca or transection of the fornix. Monkeys with subtotal lesions of the adjacent medial temporal area were not consistently impaired on any of these tasks. The results suggest that hippocampal lesions produce anterograde and retrograde amnesia for information other than reward association.

Animals↗
PubMed2003

Representational blending in human conditional learning: Implications for associative theory.

In two experiments, participants were presented with pictures of different foods (A, B, C, D, X,) and learned which combinations resulted in an allergic reaction in a fictitious patient, Mr X. In Problem 1, when A or B (but not C or D) was combined with food X an allergic reaction occurred, and when C or D (but not A or B) was combined with Y an allergic reaction occurred. In Experiment 1, participants also received Problem 2 in which A, B, C, and D interacted with foods V and W either in the same way as X and Y, respectively, or in a different way. Participants performed more proficiently in the former than in the latter condition. In Experiment 2, after training on Problem 1, participants judged whether or not novel combinations of foods (e.g., AB, CD, AD, CB) would cause an allergic reaction in Mr X. They were no more likely to indicate that AB or CD would cause an allergic reaction than AD or CB, but made their judgements more rapidly and with greater confidence on AB and CD trials than on AD and CB trials. These results (1) indicate that shared representations come to be addressed by the components of similar compounds (e.g., AX and BX) that have predicted the same outcome (an allergic reaction), and (2) are inconsistent with standard, associative theories of learning, but (3) are consistent with findings from nonhuman animals and with a connectionist interpretation of these findings.

Association↗
PubMedDate not supplied

Effects of prenatal triphenyl-tin exposure on the development of behavior and conditioned learning in rat pups.

Neurotoxic effects of the fungicide triphenyl-tin acetate were examined in pups of mothers treated perorally on day 7-15 of gestation. The gait and development of motor coordination did not differ from those of control animals, in spite of the high mortality rate of control pups during the nursing period. Spontaneous locomotor activity of treated pups at the age of 23 and 36 days was increased, however by the age of 90 days activity returned to control levels. Conditioned avoidance was acquired more rapidly, but was also extinguished sooner in animals born from, the nursed by poisoned mothers than in control.

Amphetamine↗