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Learning of event sequences is based on response-effect learning: further evidence from a serial reaction task.

Four experiments provide converging evidence that serial learning in a serial reaction task is based on response-effect learning, mediated by the learning of the relations between a response and the stimulus that follows it. In Experiment 1, the authors varied the stimulus sequence and the response-stimulus relations while holding the response sequence constant. Learning effects depended on the complexity of the response-stimulus relations but not on the stimulus-stimulus relations. In Experiment 2, transfer of serial learning from 1 stimulus sequence to another was only found when both sequences had identical response-stimulus relations. In Experiment 3, a variation of the stimulus sequence alone had no effect on serial learning, whereas in Experiment 4 learning effects increased when the response-stimulus relations but not the stimulus-stimulus relations were simplified. These findings suggest that serial learning is based on mechanisms of voluntary action control.

Adult↗

Obstacle avoidance during human walking: learning rate and cross-modal transfer.

1. The aim of this study was to investigate the significance of specific afferent information during motor learning. Blindfolded subjects stepped over an obstacle on a treadmill while different stimuli (acoustic (ACU), somatosensory (SOM) and light flash (LED)) signalled the approaching obstacle. The effect of the above stimuli was then evaluated and compared to full vision (VIS) locomotion. In the non-visual conditions feedback information about the performance was provided by an acoustic signal. 2. Using each of the different stimuli for information the level of subject performance was assessed by noting foot clearance and analysing both leg muscle electromyographic activity and movement trajectories during three successive runs. Each of these runs consisted of 100 steps over the obstacle. 3. The best performance at the onset of the first run was achieved during the VIS condition. When the VIS condition (run 1 + 2) was followed by ACU or SOM information or when the ACU condition (run 1 + 2) was followed by LED, little cross-modal transfer (CMT) occurred, i.e. adaptation in run 3 started again at a low level of performance. In contrast, if adaptation started with ACU stimuli followed by SOM stimuli, almost full CMT occurred. The absolute level of performance achieved after the second or third runs was similar in the VIS and non-VIS conditions. 4. In conclusion, the course of motor learning depends on specific afferent information, and feedforward control has a special influence on the performance only at the onset of the experiment but not on the rate of learning. The fact that little CMT occurs from visual to non-visual stimuli and from ACU to LED suggests that visual afferent input is processed in a different way to non-visual stimuli.

Acoustic Stimulation↗

The long-term effects of callosal sectioning. Report of a second case.

Testing a patient 32 years after callosal sectioning revealed defects in transfer of learning and crossed (mixed modality) matching. This points out that defects may persist long after such surgery and that early reports of negative results of callosal section in patients were probably not correct.

Adolescent↗

Organization of intracortical and commissural connections in somatosensory cortical areas I and II in the raccoon.

The organization of intracortical and callosal projecting cell bodies was examined in somatosensory representation areas I (SI) and II (SII) of the raccoon by use of horseradish peroxidase (HRP) or horseradish peroxidase-wheat germ agglutin (HRP-WHA). HRP and HRP-WHA were injected into commissurally and noncommissurally connected subdivisions of SI and SII. Injection sites in SII were identified electrophysiologically. Results were obtained from transverse sections in which the HRP was visualized with the aid of the substrates dihydrochlorobenzidine or tetramethyl benzidine in the presence of hydrogen peroxidase. The principal findings were the following: (1) there are reciprocal connections between SI and SII; (2) in SI the intracortically projecting cell bodies and terminals are located primarily in sulcal cortex; (3) intracortically projecting neurons in SI are located primarily in layers III whereas in SII they are located principally in layers III and V; (4) there are connections between disparate areas within SI; and (5) there are intracortical connections between callosum-connected and acallosal regions in SII. These results are discussed with regard to the results of mapping studies of the SI, the significance of intracortical connections to the formation of sulci in SI, and the possible roles of nonhomotopic connections in the intermanual transfer of learning.

Animals↗

Behavioral characterization of quinolinate-induced lesions of the medial striatum: relevance for Huntington's disease.

Huntington's disease (HD) in an inherited neurodegenerative disorder in which the striatum undergoes marked atrophic changes. Patients with HD typically have impaired cognitive function, including deficient visuospatial skills, lack of cognitive flexibility and poor recall of memories. The relationship between these cognitive abnormalities and the striatal degeneration of HD is incompletely understood. In order to explore this issue, we studied the behavior of rats with histologically confirmed bilateral quinolinate (QUIN)-induced lesions of the medial striatum. In a series of Morris Water Maze (MWM) experiments and Delayed Alternation (DA) tests, QUIN-lesioned animals exhibited: (i) impaired acquisition of visuospatial skills; (ii) impaired "transfer of learning"; (iii) preseverative behavior; (iv) deficient retrieval or retention of stored memories. The lesioned rats were unimpaired with swimming to a visible platform, while moving spontaneously in behavior boxes, and when performing various specialized tests of motor function. These results indicate that QUIN-induced lesions of the medial striatum can produce impairments of visuospatial skills, cognitive flexibility, and recall. These are the categories of cognitive function that are disturbed in HD. This suggests that the striatal degeneration of HD could be a sufficient explanation for the cognitive abnormalities associated with the illness.

Animals↗

Flow cytometry assay for counting micronucleated erythrocytes: development process.

Development of any new assay proceeds in several phases. When an assay is intended for regular use to support regulatory decision-making, there are significant additional stages in the development process beyond the initial description of the method. In this paper we discuss some of the studies related to the development of a flow cytometric method for counting micronuclei in rodent erythrocytes. Studies related to fixation methods and conditions, standardization of DNA staining, and antibody staining are discussed. These studies, while not part of the formal description of the method, are needed as part of the preparation for the formal validation of the method. In addition, the lessons learned in transferring the method to other laboratories are briefly discussed in relation to defining the final protocol.

Animals↗

Marijuana: effects on storage and retrieval of prose material.

In a two phase design, an attempt was made to differentiate the effect of marijuana on the storage and retrieval of prose material. In the first phase, 40 male subjects were administered a single 500 mg marijuana cigarette containing 2.1%delta9-THC or a placebo cigarette. Fifteen minutes after smoking, they listened to and at the same time read a narrative passage of approximately 200 words in length. Subsequently, an immediate free recall test was given in which subjects were required to write down as much of the story as they could remember. The second phase was conducted 24h later. Marijuana and placebo subjects were randomly subdivided into four groups with half of the subjects participating in the same drug condition as occurred on day one while the others switched drug state. Fifteen minutes after smoking, all subjects recalled the passage presented on day one and then were given 24 questions concerning facts and events in the story which could be answered in a few words. These questions served as retrieval cues. Following this, a new passage was presented in the same manner as occurred on day one. After an immediate free recall test, another cued recall test was administered. Results indicated that marijuana reduced immediate recall under both cued and uncued conditions incomparison to placebo. No relative cued recall advantage was found in the marijuana groups for the old or new story and marijuana produced only a moderate decrement in recall of the old story on day two. However, marijuana given in the second phase significantly reduced memory for items recalled in the initial phase irrespective of drug or cueing condition in phase one, suggesting that retrieval was also affected. Some decrement in recall of the new story did occur as a function of drug state change in group M-P. This effect was related to the serial position of input items. Serial position did not interact with drug state under any other recall condition.

Cannabis↗

[Simulator-based modular human factor training in anesthesiology. Concept and results of the module "Communication and Team Cooperation"].

BACKGROUND: Human factors (HF) play a major role in crisis development and management and simulator training can help to train HF aspects. We developed a modular training concept with psychological intensive briefing. The aim of the study was to see whether learning and transfer in the treatment group (TG) with the module "communication and team-cooperation" differed from that in the control group (CG) without psychological briefing ("anaesthesia crisis resource management type course"). METHODS: A total of 34 residents (TG: n=20, CG: n=14) managed 1 out of 3 scenarios and communication patterns and management were evaluated using video recordings. A questionnaire was answered at the end of the course and 2 months later participants were asked for lessons learnt and behavioral changes. RESULTS: Good communication and medical management showed a significant correlation (r=0.57, p=0.001). The TG showed greater initiative ( p=0.001) and came more often in conflict with the surgeon ( p=0.06). The TG also reported more behavioral changes than the CG 2 months later. The reported benefit of the simulation was training for rare events in the CG, whereas in the TG it was issues of communication and cooperation ( p=0.001). CONCLUSIONS: A training concept with psychological intensive briefing may enhance the transfer of HF aspects more than classical ACRM.

Anesthesia↗

Selective attention and Pavlovian conditioning.

The present results show that the common practice of using self-indexing conditioned stimuli (CSs) in research on Pavlovian conditioning is a major source of experimental bias. The typical stimulus used is either a light flash or a sound pulse in a light/sound-shielded chamber. Under these conditions the onset characteristics of the CS signal totally predominate over the durational characteristic, i.e. the pattern information. Thus a visual pattern presented as a CS in a dark chamber is confounded with a brightness change from darkness to light. In the first experiment, animals were conditioned with a brightness CS using a self-indexing signal paradigm. When tested for specificity of the conditioning, they showed complete transfer of learning to either a visual pattern or even an auditory CS. These findings indicated that the traditional conditioning paradigm is biased towards non-specific sensory learning. The second experiment showed that specific sensory conditioning is critically dependent on selective attention mechanisms. When the onset characteristics of the CS signal were de-emphasized by the use of equal energy background illumination in the intertribal interval (ITI) during conditioning, the animals were not able to feature extract either the onset or the durational component of the CS signal from the ITI background despite prolonged training. It was only by starting with conditioning that was initially anchored to the CS onset characteristics that a perceptual fade-in procedure would bias attention to feature extract the durational characteristics of the CS. Thus conditioning occurred only when the rabbit's attention was directed to detection of the gratings display without any associated changes in visual albedo. Perhaps the most important finding of the present experiments is that the use of self-indexing CS signals in Pavlovian conditioning inevitably introduces non-specific sensory processing involving multiple sensory input pathways in the conditioning. This inherent uncertainty of the sensory input pathways presents a problem for clarifying the role of sensory pathways in the neural mechanisms of NM conditioning. In addition, the use of self-indexing CSs inevitably leads to an underestimation of the role of forebrain mechanisms in Pavlovian conditioning.

Acoustic Stimulation↗

Teaching communication and stress management skills to junior physicians dealing with cancer patients: a Belgian Interuniversity Curriculum.

BACKGROUND: Ineffective physicians' communication skills have detrimental consequences for patients and their relatives, such as insufficient detection of psychological disturbances, dissatisfaction with care, poor compliance, and increased risks of litigation for malpractice. These ineffective communication skills also contribute to everyday stress, lack of job satisfaction, and burnout among physicians. Literature shows that communication skills training programs may significantly improve physicians' key communication skills, contributing to improvements in patients' satisfaction with care and physicians' professional satisfaction. This paper describes a Belgian Interuniversity Curriculum (BIC) theoretical roots, principles, and techniques developed for junior physicians specializing in various disciplines dealing with cancer patients. CURRICULUM DESCRIPTION: The 40-h training focuses on two domains: stress management skills and communication skills with cancer patients and their relatives. The teaching method is learner-centered and includes a cognitive, behavioral, and affective approach. The cognitive approach aims to improve physicians' knowledge and skills on the two domains cited. The behavioral approach offers learners the opportunity to practice these appropriate skills through practical exercises and role plays. The affective approach allows participants to express attitudes and feelings that communicating about difficult issues evoke. Such an intensive course seems to be necessary to facilitate the transfer of learned skills in clinical practice. CONCLUSIONS: The BIC is the first attempt to bring together a stress management training course and a communication training course that could lead not only to communication skills improvements but also to burnout prevention.

Adaptation, Psychological↗

Behavioural factors influencing the use of flight simulators for training.

The case for using flight simulators as a training aid is propounded, and the drawbacks of training entirely in flight are listed. Transfer of learning from the simulated to real-life situation is discussed with relevant examples. A diagram illustrating the relative cost of using different types of simulator is given, and recent research is discussed. Finally, the attitude and influence of the organisation to simulator, trainee and instructor is described.

Journal Article↗

Role of neocortex in binaural hearing in the cat. II. The 'precedence effect' in sound localization.

The 'precedence effect' in sound localization refers to the situation in which two speakers, separated in space, emit identical sounds but one speaker leads by a few milliseconds. Normal observers perceive all the sound as originating from the leading speaker. In the present experiment cats were tested before and after unilateral ablation of auditory cortex on how well they could transfer a learned sound loclization response from situations involving unpaired sound sources to those with paired sources. Cats were tested with tone pairs separated by 5 msec and with clicks separated by delays of 3, 5, 7, 9, 12 and 16 msec. Preoperatively, the cats averaged 98% correct at a delay of 3 msec and 58% correct at 16 msec. Before surgery the probability of an error was independent of which speaker was leading; after surgery cats made significantly more errors when the leading speaker was located opposite the side of the lesion. Considerable individual variability was found with the 3 and 5 msec delay tests; some cats showed no evidence of a cortical deficit while others exhibited initial severe deficits which disappeared with training. At delays of 7-16 msec all cats showed severe directional deficits which were still present after 9 months of retraining. Results are interpreted as supporting the hypothesis that unilateral lesions disrupt binaural loudness rather than temporal relations.

Animals↗