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PubMed1995

The rise and fall of a radiologic technique.

As young radiologists read the slightly self-satisfied articles celebrating the centennial of radiology, they may conclude that the course of radiology and all its components has been smoothly upward, without hesitations, false starts, or disappointments. Older radiologists know better. The replacement of a less satisfactory technique with a better one is a gain for both patients and physicians, but the replacement process itself can be distressing. Much of what radiology residents learned in the 1950s and 1960s is no longer of any use. Who now employs pneumoencephalography or intravenous cholangiography? Entire books were once written about these procedures [1, 2]. Who can now credit the reliance once placed on positive-contrast maxillary antrography [3]? Few have even heard of eustachian tubography [4]. Radiologists who tried to make a career using those techniques learned to their sorrow that although anatomy is permanent and diseases change only slowly, techniques are often ephemeral. Total body opacification, a technique once of consuming interest to the present writers [5-7], is an illustration of this.

History, 20th Century↗
PubMed2003

Direct versus indirect emotional consequences on the Iowa Gambling Task.

The Iowa Gambling Task has been widely used in the assessment of neurological patients with ventro-mesial frontal lesions. The Iowa Group has claimed that the Gambling Task is too complex for participants to follow using cognition alone, so that participants must rely on emotion-based learning systems (somatic markers). The present study investigates whether similar tasks can be performed without direct somatic markers. In a 'Firefighter' task closely matched to the classic Gambling Task, participants evaluate the performance of others--so that they experience reward and punishment indirectly. In contrast to the gradual improvement in performance seen on the classic Iowa Gambling Task, participants on the Firefighter Task showed no learning effect, mirroring the performance of patients with ventro-mesial frontal lesions, and suggesting that the task is very difficult to perform without direct somatic marker information. The use of this task as empirical measure of 'empathy' are discussed.

Adult↗
PubMed1988

Main effects of current and pimozide on prepared and learned self-stimulation behaviors are on performance not reward.

This work examined four independent variables which influence behavior of self-stimulating rats: site of electrode placement (cingulate cortex versus lateral hypothalamus), type of operant response (lever press versus nose poke), current intensity (50, 100, 150 microA) and pimozide dosage (0.125, 0.250, 0.500 mg/kg). The dependent measures were: total responding, alternation between two identical manipulanda and mean duration per response. Naive rats made more nose pokes than lever presses, suggesting nose pokes are more "prepared." The cingulate cortex was insensitive to current and pimozide manipulations in contrast with hypothalamic sensitivity, tentatively suggesting a cingulate role in release of prepared behaviors, hypothalamic in plasticity of learned ones. Lever pressing, more prevalent with lateral hypothalamic stimulation, was more affected by current and pimozide manipulations than nose poking. More prepared nose pokes might thus be less susceptible to brain stimulation reward manipulations. Intensifying current produced more but shorter responses, increasing pimozide dosage produced fewer and nonsignificantly longer ones, suggesting a primary effect on motor performance not reward. Decrements in performance over nondrug days were tentatively attributed to long-lasting effects of pimozide.

Animals↗
PubMed2003

Using arm configuration to learn the effects of gyroscopes and other devices.

Previous studies have perturbed the association between motor commands and arm movements by applying forces to the arm during two-dimensional movements. These studies have revealed that, when the normal hand path is perturbed, subjects gradually adapt their motor commands to return to this path. The present study used the spin of a gyroscope to create a complex perturbation, as subjects reached to targets presented in three dimensions. Hand path did not change, but the whole-arm geometry ("arm configuration" in four dimensions) was altered. Over a series of several hundred reaches to various targets, subjects gradually returned the arm movement to its normal configuration. Furthermore, during the course of this learning, subjects used a strategy that involved manipulating arm posture. A similar strategy was observed when subjects made reaching movements with a rod attached to the upper arm to change its inertial characteristics. In both cases, the gradual return to the normal arm movement was accomplished without an increase in kinetic energy, suggesting that arm postures and movements (kinematics) and muscular forces (kinetics) may be mutually optimized. In contrast to previous studies, the present results highlight the role of arm configuration (rather than hand path) in learning and control.

Adaptation, Physiological↗
PubMed2004

Range of neurologic disorders in patients with celiac disease.

OBJECTIVE: During the past 2 decades, celiac disease (CD) has been recognized as a multisystem autoimmune disorder. A growing body of distinct neurologic conditions such as cerebellar ataxia, epilepsy, myoclonic ataxia, chronic neuropathies, and dementia have been reported, mainly in middle-aged adults. There still are insufficient data on the association of CD with various neurologic disorders in children, adolescents, and young adults, including more common and "soft" neurologic conditions, such as headache, learning disorders, attention-deficit/hyperactivity disorder (ADHD), and tic disorders. The aim of the present study is to look for a broader spectrum of neurologic disorders in CD patients, most of them children or young adults. METHODS: Patients with CD were asked to fill in a questionnaire regarding the presence of neurologic disorders or symptoms. Their medical charts were reviewed, and those who were reported as having neurologic manifestations underwent neurologic examination and brain imaging or electroencephalogram if required. Their neurologic data were compared with that of a control group matched for age and gender. RESULTS: Patients with CD were more prone to develop neurologic disorders (51.4%) in comparison with control subjects (19.9%). These disorders include hypotonia, developmental delay, learning disorders and ADHD, headache, and cerebellar ataxia. Epileptic disorders were only marginally more common in CD. In contrast, no difference was found in the prevalence of tic disorders in both groups. Therapeutic benefit, with gluten-free diet, was demonstrated only in patients with transient infantile hypotonia and migraine headache. CONCLUSION: This study suggests that the variability of neurologic disorders that occur in CD is broader than previously reported and includes "softer" and more common neurologic disorders, such as chronic headache, developmental delay, hypotonia, and learning disorders or ADHD. Future longitudinal prospective studies might better define the full range of these neurologic disorders and their clinical response to a gluten-free diet.

Adolescent↗
PubMed1997

Abrupt learning and retinal size specificity in illusory-contour perception.

BACKGROUND: In behavioral studies of learning, a distinction is commonly made between gradual and abrupt improvements in performance. The learning of perceptual and motor skills is often characterized by gradual, incremental improvement, and is found not to generalize over stimulus manipulations such as changes in the size or location of the retinal image. In contrast, marked improvement in performance can occur suddenly - a phenomenon which has been termed 'insight'. Consequently, the brain mechanisms subserving the two types of learning are commonly thought of as distinct. Here, we examine learning of a perceptual task in which improvement appears to exhibit characteristics of both gradual and abrupt learning. RESULTS: We describe experiments on illusory-contour perception in which the observers underwent an abrupt, dramatic improvement in performance, resembling an incident of insight. At the same time, however, the phenomenon showed a degree of stimulus-specificity that was previously thought to characterize incremental, gradual learning. The improvement was triggered only by specific visual stimuli, whereas other, quite similar, stimuli were found to be ineffective for training; the learning did not generalize to a new retinal image size, and re-training was necessary for different-sized images. CONCLUSIONS: The juxtaposition of abrupt and stimulus-specific learning that we observed suggests that the distinction between the two forms of learning needs to be revised. Rather than postulating two distinct mechanisms, incremental and insightful learning need to be addressed within a single framework. In particular, the findings suggest that learning may involve interactions between multiple levels of representations of the stimulus.

Adolescent↗
PubMed2004

Learning as a task or a virtue: U.S. And Chinese preschoolers explain learning.

The purpose of this study was to examine cultural influences on conceptual orientations of learning in U.S. and Chinese preschoolers. A sample of 188 preschoolers 4-6 years of age provided free-narrative responses to 2 story beginnings about the learning behavior of 2 protagonists, 1 who worked hard and 1 who gave up. Results showed that despite some differences in the younger age groups, children from both cultures valued learning similarly at age 6. However, important cultural differences emerged in children's construals of the learning process. U.S. children showed a heightened awareness of the mind/task attributes of the learner, that is, ability, task attempting, and strategy use. By contrast, Chinese children perceived more the learner's dispositional qualities of diligence, persistence, and concentration. These trends increased as children's age increased. The U.S. findings are interpreted as reflecting the U.S. cultural emphasis on learning as a task, and the Chinese results, as reflecting the Chinese cultural focus on learning as a process of cultivating personal virtue.

Attitude↗
PubMed2025

Three-dimensional U-Net with transfer learning improves automated whole brain delineation from MRI brain scans of rats, mice, and monkeys.

BACKGROUND: Automated whole-brain delineation (WBD) techniques often struggle to generalize across pre-clinical studies due to variations in animal models, magnetic resonance imaging (MRI) scanners, and tissue contrasts. We developed a 3D U-Net neural network for WBD pre-trained on organophosphate intoxication (OPI) rat brain MRI scans. We used transfer learning (TL) to adapt this OPI-pretrained network to other animal models: rat model of Alzheimer's disease (AD), mouse model of tetramethylenedisulfotetramine (TETS) intoxication, and titi monkey model of social bonding. METHODS: We assessed an OPI-pretrained 3D U-Net across animal models under three conditions: (1) direct application to each dataset; (2) utilizing TL; and (3) training disease-specific U-Net models. For each condition, training dataset size (TDS) was optimized, and output WBDs were compared to manual segmentations for accuracy. RESULTS: The OPI-pretrained 3D U-Net (TDS = 100) achieved the best accuracy [median[min-max]] for the test OPI dataset with a Dice coefficient (DC) = [0.987 [0.977-0.992]] and Hausdorff distance (HD) = [0.86 [0.55-1.27]]mm. TL improved generalization across all models [AD (TDS = 40): DC = 0.987 [0.977-0.992] and HD = 0.72 [0.54-1.00]mm; TETS (TDS = 10): DC = 0.992 [0.984-0.993] and HD = 0.40 [0.31-0.50]mm; Monkey (TDS = 8): DC = 0.977 [0.968-0.979] and HD = 3.03 [2.19-3.91]mm], showing performance comparable to disease-specific networks. CONCLUSIONS: The OPI-pretrained 3D U-Net with TL achieved accuracy comparable to disease-specific networks with reduced training data (TDS ≤ 40 scans) across all models. Future work will focus on developing a multi-region delineation pipeline for pre-clinical MRI brain data, utilizing the proposed WBD as an initial step.

Animals↗
PubMed1995

Parkinson's disease affects automatic and spares intentional verbal learning. A stochastic approach to explicit learning processes.

We studied word list and paired associates learning in patients with idiopathic Parkinson's disease and normal controls by means of a two-stage stochastic model, which allows independent measurements of encoding, storage and retrieval abilities. We preliminarily ascertained that the model components were both sufficient and necessary to account for the overall performance of the subjects, and then compared the learning abilities between the two groups. Parkinson's disease patients were selectively impaired in identifying well-known engrams, for which learning is superfluous, and in automatic retrieval, namely in abilities that do not need attentional effort. By contrast, they were unimpaired in encoding and intentional retrieval, which require a purposeful effort. The automatic-voluntary dissociation of Parkinson's disease patients' motor behaviour is, therefore, paralleled by some features of their memory performance.

Aged↗
PubMed2002

A combined pharmacological and genetic approach to investigate the role of orphanin FQ in learning and memory.

Using a combination of the selective opioid receptor-like1 (ORL1) receptor agonist, Ro 64-6198, and orphanin FQ/nociceptin (OFQ/N) peptide knockout (KO) mice, the influence of OFQ/N on cognition has been studied in the rodent. In wild type, C57BL/6J mice, Ro 64-6198 (0.3-1 mg/kg i.p.) impaired the acquisition of spatial learning in the Morris water maze, although a mild neurological impairment was evident which complicated precise interpretation. In Lister hooded rats, Ro 64-6198 (6 mg/kg i.p.) produced delay dependent impairments in rats performing either a delayed matching or a delayed nonmatching to position task with only a modest (< 20%) effect on omissions - an effect consistent with a short-term memory impairment. Electrophysiological studies demonstrated an inhibitory effect of OFQ/N on LTP recorded from the CA1 region of wild type mice, but not in ORL1 receptor knockout mice. In contrast to the ORL1 agonist, mice deficient in the OFQ/N peptide showed some evidence of improved spatial learning, fear conditioning and passive avoidance retention. However, CA1 LTP was similar between OFQ/N peptide KO mice and wild type controls. Subsequent receptor radioautography studies demonstrated the presence of ORL1 receptors within various regions of the medial temporal lobe system: i.e. CA1, dentate gyrus molecular layer, subiculum, perirhinal cortex. Taken together, these results suggest a bi-directional effect of OFQ/N containing systems on aspects of cognitive behaviour, particularly those elements associated with hippocampal function. This is consistent with a likely modulatory role of OFQ/N on hippocampal and associated cortical circuitry.

Animals↗
PubMed2004

[To promote the change of health education orientation and to incorporate the Spanish universities to the task].

The problem health education faces in Spanish schools is the inconsistency between objectives and means. Therefore, it is common to find health education initiatives limited by not only lack of institutional support and training of professionals, but also by its adherence to a theory-based learning. This article analyses the need for a practical alternative, which would involve researchers/teachers and students in thinking and building the best health practices for them and their community. Parent-like behaviour, based on information and/or persuasion, looks to protect adolescent health and well-being until they are able to take on responsibility of their own, despite the fact that adolescents' search for knowledge influences their own perceptions of what is best for individual and community health. In order to tackle this challenge faced by health educators, in contrast to the theory-based teaching model, it is necessary to implicate the people into the learning process. An in depth study on the definition of health education paradigms (informative, persuasive and political-ecological) (García et al., 2001) has been developed, and which Jensen (1997) divides into two types: moral (informative) and democratic (ecological). As part of this process to transform health education into a participatory practice, and given its social impact, there is also a need to implement health education at higher educational levels and not only in primary and secondary school as occurs in Spain. Turning universities into 'health promoting agencies' (Dooris, 2001) would imply coordinating education with personal, professional and community action, and would be supported and driven by organisational change at university level and would require the participation of all involved when defining the course of action. As a consequence, the people involved in health education learning processes at university level would improve not only their quality of life, but they would also build capacity to influence the different sectors of society they are in contact with (Toyne and Ali-Khan, 1998.).

Health Education↗
PubMed2005

Robust self-localisation and navigation based on hippocampal place cells.

A computational model of the hippocampal function in spatial learning is presented. A spatial representation is incrementally acquired during exploration. Visual and self-motion information is fed into a network of rate-coded neurons. A consistent and stable place code emerges by unsupervised Hebbian learning between place- and head direction cells. Based on this representation, goal-oriented navigation is learnt by applying a reward-based learning mechanism between the hippocampus and nucleus accumbens. The model, validated on a real and simulated robot, successfully localises itself by recalibrating its path integrator using visual input. A navigation map is learnt after about 20 trials, comparable to rats in the water maze. In contrast to previous works, this system processes realistic visual input. No compass is needed for localisation and the reward-based learning mechanism extends discrete navigation models to continuous space. The model reproduces experimental findings and suggests several neurophysiological and behavioural predictions in the rat.

Animals↗
PubMed2004

Verbal memory errors and symptoms in schizophrenia.

OBJECTIVE: To extend and test hypotheses linking positive and negative symptoms to selective aspects of verbal memory in schizophrenia. BACKGROUND: Verbal memory includes the ability to discriminate and prevent the intrusion of irrelevant information into recall and recognition. This ability has been proposed as a cognitive process that differentially mediates positive and negative symptoms. METHOD: Four error discrimination and 1 general recall memory index from the California Verbal Learning Test as well as general ability (IQ) and sex were used as predictors of symptom ratings in 55 schizophrenia patients within a regression framework. RESULTS: Intrusion errors during free recall contributed significantly to the prediction equation for negative symptoms (Brief Psychiatric Rating Scale). In contrast, positive symptoms and general psychopathology were not predicted by any of the discrimination indices. However, general recall memory (California Verbal Learning Test total words trials 1-5) contributed significantly to the prediction of general psychopathology and marginally to the prediction of negative symptoms. CONCLUSIONS: Impaired recall memory predicts levels of nonspecific psychopathology in schizophrenia. Negative symptoms associate with low intrusion error rates, but there is no evidence of an association between elevated errors and positive symptoms.

Adult↗
PubMed2006

Treatment-induced prevention of learning deficits in newborn mice with brain lesions.

Perinatal brain injuries often result in irreversible learning disabilities, which manifest in early childhood. The molecular and cellular mechanisms of these injuries and potential pharmacological treatments are emerging, chiefly from studies in newborn rodents. In newborn mice, experimentally induced lesions can be dramatically reduced by appropriate neuroprotective treatments. However, the early effectiveness of these treatments in preserving cognition remained unknown. Here, we addressed this issue by using intracerebral ibotenate to induce excitotoxic brain lesions in 5-day-old mice (postnatal day 5). On postnatal days 6-7, we tested spontaneous preference for maternal odors, as an index of odor memory, and conditioned preference for an artificial odor previously paired with stroking, as an index of associative learning. Brain-lesioned newborn mice showed normal general status and preference for maternal odors. In contrast, odor conditioning was severely impaired. A previous study showed that fructose 1,6-biphosphate acted as a neuroprotective agent which significantly reduced neocortical lesion size. In the present study, treating the newborn mice with fructose 1,6-biphosphate 15 min before the ibotenate injection reduced neocortical lesion size and restored conditioning. This demonstrates, for the first time, that neuroprotective treatment can protect some features of early cognition.

Animals↗
PubMed2000

The beta-amyloid precursor protein and its derivatives: from biology to learning and memory processes.

Intensive investigation towards the understanding of the biology and physiological functions of the beta-amyloid precursor protein (APP) have been supported since it is known that a 39-43 amino acid fragment of APP, called the beta-amyloid protein (Abeta), accumulates in the brain parenchyma to form the typical lesions associated with Alzheimer's disease (AD). It emerges from extensive data that APP and its derivatives show a wide range of contrasting physiological properties and therefore might be involved in distinct physiological functions. Abeta has been shown to disrupt neuronal activity and to demonstrate neurotoxic properties in a wide range of experimental procedures. In contrast, both in vitro and in vivo studies suggest that APP and/or its secreted forms are important factors involved in the viability, growth and morphological and functional plasticity of nerve cells. Furthermore, several recent studies suggest that APP and its derivatives have an important role in learning and memory processes. Memory impairments can be induced in animals by intracerebral treatment with Abeta. Altered expression of the APP gene in aged animals or in genetically-modified animals also leads to memory deficits. By contrast, secreted forms of APP have recently been shown to facilitate learning and memory processes in mice. These interesting findings open novel perspectives to understand the involvement of APP in the development of cognitive deficits associated with AD. In this review, we summarize the current data concerning the biology and the behavioral effects of APP and its derivatives which may be relevant to the roles of these proteins in memory and in AD pathology.

Alzheimer Disease↗
PubMed2003

Facilitating effective radiation safety workshops: adult learning theories.

One of the primary responsibilities of radiation safety officers and staff is to maintain a continuing learning environment for their businesses and institutions. In the current business climate, there continues to be a trend for shorter and shorter training classes for regulatory-required radiation safety training. The "workshop" has often been utilized to assist in providing information, required training, awareness issues, as well as a forum for question and answer periods in a shorter (e.g., 1-4 h) format. In an effort to facilitate more effective workshops, a literature review of basic adult learning theories and research was performed. This review identified four adult learning inquiry areas that encompass various assumptions, theories, processes, and practical approaches as well as research areas. Each of these areas of inquiry is discussed, compared, contrasted, and summarized. From this evaluation, key principles related to educating adults in a workshop environment are identified. This collection of concepts can be considered and practically applied when developing radiation safety learning workshops.

Adult↗
PubMed2002

Goal orientation and ability: interactive effects on self-efficacy, performance, and knowledge.

This study examined the direct relationship of goal orientation--and the interaction of goal orientation and cognitive ability--with self-efficacy, performance, and knowledge in a learning context. The authors argue that whether a particular type of goal orientation is adaptive or not adaptive depends on individuals' cognitive ability. Consistent with previous research, learning orientation was positively related to self-efficacy, performance, and knowledge, whereas performance orientation was negatively related to performance only. The interactions between goal orientation and ability also supported several hypotheses. As expected, learning orientation was generally adaptive for high-ability individuals but had no effect for low-ability individuals. In contrast, the effects of performance orientation were contingent on both individuals' level of cognitive ability and the outcome examined.

Adaptation, Psychological↗