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PubMed1998

Visual control of the arm, the wrist and the fingers: pathways through the brain.

Sperry and his colleagues had shown that section of the corpus callosum blocks the normally strong interocular transfer of visual learning in chiasma sectioned monkeys. Although interhemispheric transfer of learning was blocked, monkeys could be readily trained to use any combination of eye and hand in a task that required rapid visually guided responses. Sperry suggested that there must be a subcortical pathway linking sensory to motor areas of the brain. We tested monkeys in a task which required them to orient their wrist and fingers correctly in order to remove a morsel of food from a slotted disc. Animals in which we made lesions of the dorsal extrastriate visual areas of the parietal lobe were profoundly impaired in performing this task, but showed no deficit in visual discrimination learning. A monkey with an extensive lesion of the ventral, temporal lobe extrastriate areas showed no deficit in the visuomotor task but was profoundly impaired in visual discrimination learning. Lesions of peri-arcuate cortex, a major cortical target of parietal lobe visual areas, produced only a mild deficit which was motor in character. We suggest that the visuomotor deficit caused by parietal lobe lesions is brought about by depriving the cerebellum of its cortical visual input.

Animals↗
PubMed1987

Zygote viability in gene transfer experiments.

To learn why some zygotes remain viable after gene transfer while others lyse, we injected DNA into fertilized eggs and compared those that lysed within 1 h of injection with others that retained a normal appearance. Using scanning electron microscopy, we found open holes on the surface of lysed eggs, indicating failure of the plasma membrane to reseal after microinjection. No holes were seen in unlysed eggs, but many of them had membrane alterations suggestive of healed punctures. We also examined aspects of the gene transfer procedure that might influence survival such as the size of injection pipettes and their taper relative to zygote diameter, possible toxicity of the injection medium, the timing of injection, and immediate vs. delayed pipette withdrawal. The only factors that significantly affected cell viability were pipette size and taper, and timing of injection in relation to first cleavage. This suggests that zygote viability correlates inversely with the size of the hole produced by the injection pipette and that damage to the membrane is less successfully repaired as the fertilized egg readies itself for division.

Animals↗
PubMed2006

Interactions between encoding and retrieval in the domain of sequence-learning.

In this article, the authors propose to characterize sequence learning in terms of automatic versus non-automatic processing and to apply this contrast independently to knowledge acquisition and retrieval. In several experiments of sequence learning, automaticity of both the acquisition and retrieval of the acquired knowledge was independently assessed. It was found that the sequence learning order can be demonstrated under all combinations of knowledge acquisition and retrieval. In particular, at least in the simple sequences the authors used, this applies in cases in which both the acquisition and the retrieval of knowledge are strictly automatic--that is, when neither is required for the task nor beneficial to deliberate behavior. The proposed framework has implications for the notion of sequence learning and the investigation of learning in general.

Association Learning↗
PubMed2001

Fiberoptic orotracheal intubation on anesthetized patients: do manipulation skills learned on a simple model transfer into the operating room?

BACKGROUND: With increasing pressure to use operating room time efficiently, opportunities for residents to learn fiberoptic orotracheal intubation in the operating room have declined. The purpose of this study was to determine whether fiberoptic orotracheal intubation skills learned outside the operating room on a simple model could be transferred into the clinical setting. METHODS: First-year anesthesiology residents and first- and second-year internal medicine residents were recruited. Subjects were randomized to a didactic-teaching-only group (n = 12) or a model-training group (n = 12). The didactic-teaching group received a detailed lecture from an expert bronchoscopist. The model-training group was guided, by experts, through tasks performed on a simple model designed to refine fiberoptic manipulation skills. After the training session, subjects performed a fiberoptic orotracheal intubation on healthy, consenting, anesthetized, paralyzed female patients undergoing elective surgery with predicted "easy" laryngoscopic intubations. Two blinded anesthesiologists evaluated each subject. RESULTS: After the training session, the model group significantly outperformed the didactic group in the operating room when evaluated with a global rating scale (P < 0.01)and checklist (P0.05). Model-trained subjects completed the fiberoptic orotracheal intubation significantly faster than didactic-trained subjects (P < 0.01). Model-trained subjects were also more successful at achieving tracheal intubation than the didactic group (P < 0.005). CONCLUSION: Fiberoptic orotracheal intubation skills training on a simple model is more effective than conventional didactic instruction for transfer to the clinical setting. Incorporating an extraoperative model into the training of fiberoptic orotracheal intubation may greatly reduce the time and pressures that accompany teaching this skill in the operating room.

Adult↗
PubMed1975

Differential transfer in poor and normal readers.

It has been suggested that children who sustain specific reading disability experience difficulty in abstracting and generalizing the invariant components of words containing redundant elements because of basic dysfunction in categorical processing. This hypothesis was assessed by comparing independent samples of poor and normal readers on transfer of training tasks of two different types: a visual-verbal association task which simulated the reading process, and a visual-visual association task unlike reading. It was predicted that poor readers would perform significantly below normal readers on both initial learning and transfer under the visual-verbal association conditions. In contrast, it was expected that the performance of similar groups of poor and normal readers would be comparable under the visual-visual training and transfer conditions. The results supported these predictions, and it was concluded that the generalization problems observed in poor readers in early word learning are, most likely, attributable to transfer difficulties associated with specific disorder in visual-verbal integration, rather than primary or basic disorder in categorization ability.

Achievement↗
PubMed2005

L-dopa impairs learning, but spares generalization, in Parkinson's disease.

In this study we examined the effect of dopaminergic modulation on learning and memory. Parkinson's patients were tested 'on' versus 'off' dopaminergic medication, using a two-phase learning and transfer task. We found that dopaminergic medication was associated with impaired learning of an incrementally acquired concurrent discrimination task, while patients withdrawn from dopaminergic medication performed as well as controls. In addition, we found a dissociation of the effect of medication within a single two-phase task: patients tested 'on' medication were not impaired at the ability to generalize based on learned information. The deficit among medicated patients appeared to be related specifically to the concurrent, incremental, feedback-based nature of the task: such a deficit was not found in a version of the task in which demands for concurrent error-processing learning were reduced. Taken together with a growing body of evidence emphasizing a role for midbrain dopamine in error-correcting, feedback-based learning processes, the present results suggest a framework for understanding previously conflicting results regarding the effect of medication on learning and memory in Parkinson's disease.

Aged↗
PubMed2001

Teaching Bayesian reasoning in less than two hours.

The authors present and test a new method of teaching Bayesian reasoning, something about which previous teaching studies reported little success. Based on G. Gigerenzer and U. Hoffrage's (1995) ecological framework, the authors wrote a computerized tutorial program to train people to construct frequency representations (representation training) rather than to insert probabilities into Bayes's rule (rule training). Bayesian computations are simpler to perform with natural frequencies than with probabilities, and there are evolutionary reasons for assuming that cognitive algorithms have been developed to deal with natural frequencies. In 2 studies, the authors compared representation training with rule training; the criteria were an immediate learning effect, transfer to new problems, and long-term temporal stability. Rule training was as good in transfer as representation training, but representation training had a higher immediate learning effect and greater temporal stability.

Algorithms↗
PubMed2004

Evaluation of a surgical simulator for learning clinical anatomy.

BACKGROUND: New techniques in imaging and surgery have made 3-dimensional anatomical knowledge an increasingly important goal of medical education. This study compared the efficacy of 2 supplemental, self-study methods for learning shoulder joint anatomy to determine which method provides for greater transfer of learning to the clinical setting. METHODS: Two groups of medical students studied shoulder joint anatomy using either a second-generation virtual reality surgical simulator or images from a textbook. They were then asked to identify anatomical structures of the shoulder joint as they appeared in a videotape of a live arthroscopic procedure. RESULTS: The mean identification scores, out of a possible score of 7, were 3.1 +/- 1.3 for the simulator group and 2.9 +/- 1.5 for the textbook group (P = 0.70). Student ratings of the 2 methods on a 5-point Likert scale were significantly different. The simulator group rated the simulator more highly as an effective learning tool than the textbook group rated the textbook (means of 3.2 +/- 0.7 and 2.6 +/- 0.5, respectively, P = 0.02). Furthermore, the simulator group indicated that they were more likely to use the simulator as a learning tool if it were available to them than the textbook group was willing to use the textbook (means of 4.0 +/- 1.2 and 3.0 +/- 0.9, respectively, P = 0.02). CONCLUSION: Our results show that this surgical simulator is at least as effective as textbook images for learning anatomy and could enhance student learning through increased motivation. These findings provide insight into simulator development and strategies for learning anatomy. Possible explanations and future research directions are discussed.

Anatomy↗
PubMed2004

Acquisition and generalization of visuomotor transformations by nonhuman primates.

The kinematics of straight reaching movements can be specified vectorially by the direction of the movement and its extent. To explore the representation in the brain of these two properties, psychophysical studies have examined learning of visuomotor transformations of either rotation or gain and their generalization. However, the neuronal substrates of such complex learning are only beginning to be addressed. As an initial step in ensuring the validity of such investigations, it must be shown that monkeys indeed learn and generalize visuomotor transformations in the same manner as humans. Here, we analyze trajectories and velocities of movements as monkeys adapt to either rotational or gain transformations. We used rotations with different signs and magnitudes, and gains with different signs, and analyzed transfer of learning to untrained movements. The results show that monkeys can adapt to both types of transformation with a time course that resembles human learning. Analysis of the aftereffects reveals that rotation is learned locally and generalizes poorly to untrained directions, whereas gain is learned more globally and can be transferred to other amplitudes. The results lend additional support to the hypothesis that reaching movements are learned locally but can be easily rescaled to other magnitudes by scaling the peak velocity. The findings also indicate that reaching movements in monkeys are planned and executed very similarly to those in humans. This validates the underlying presumption that neuronal recordings in primates can help elucidate the mechanisms of motor learning in particular and motor planning in general.

Animals↗
PubMed2003

Effect of two different videotaped instructional models on motor and verbal behaviors of adults' lifting: a pilot study.

This study examined two different videotaped instructional models on subsequent motor and verbal behaviors of adults (N=9) learning how to lift properly. The correct model group viewed a narrated videotape of a skilled individual demonstrating lifting; the learning model group viewed a videotape of an unskilled individual being taught lifting by an instructor, and the controls received no intervention. Adults lifted from floor to waist a plastic crate during 15 acquisition and 3 retention trials and lowered the crate from waist to floor during 3 transfer trials. Learning and correct model motor performances were similar yet higher than those of controls during acquisition and transfer trials. Verbal reports indicated learning, and correct models generated more extensive and associated mechanical concepts than controls yet rarely monitored such concepts during performance. A single presentation of videotapes of proper lifting using either correct or learning models is effective in enhancing motor performance and proper lifting knowledge.

Adolescent↗
PubMed1979

The role of binocular neurons in the cat striate cortex in combining information from the two eyes.

Cats were raised under conditions of daily alternating monocular exposure, so that each eye received normal input, but the animals were never allowed to use both eyes simultaneously. With single cell recording techniques it could be shown that this led to a severe disturbance of the normal binocularity of cortical neurons. The cats were trained by operant techniques in a two-choice box to discriminate with each eye non-retinotopic stimulus pairs. To test the ability to combine binocular signals it was tested whether the learned discrimination would transfer to red/green colored stimuli which were viewed dichoptically through appropriately colored contract lenses. The arrangement was such that the positive stimulus could be distinguished from the negative stimuli only when the signals from both eyes were combined and used simultaneously. All cats showed immediate transfer, from the monocularly learned discrimination task to the dichoptic paradigm. This indicates that the presence of a normal population of binocular cortical cells in area 17 is not a prerequisite for the ability to use binocular cues for the solution of a pattern discrimination task.

Animals↗
PubMed1984

A lack of interocular transfer of spatial conditional discrimination in pigeons.

Pigeons were monocularly trained to peck one of two keys according to the color of the keys. In one task two keys were horizontally mounted on the front panel of the experimental chamber, and in the other task two keys were mounted vertically. Pigeons did not show interocular transfer of either task. The failure of the transfer was discussed in terms of role of visuomotor integration in interocular transfer of learning.

Animals↗