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PubMed2000

Adult learning deficits after neonatal exposure to D-methamphetamine: selective effects on spatial navigation and memory.

The effects of neonatal d-methamphetamine (MA) treatment on cued and spatial learning and memory were investigated. MA was administered to neonatal rats on postnatal days 11-20. All groups received four subcutaneous injections per day. Group MA40-4 received 40 mg. kg(-1). d(-1) of MA in four divided doses (10 mg/kg per injection). Group MA40-2 received 40 mg. kg(-1). d(-1) of MA in two divided (20 mg/kg/injection) and saline for the other two injections per day. Controls received saline for four injections per day. As adults, both MA groups showed no differences in swimming ability in a straight swimming channel. The MA40-4 group showed no differences in cued learning, but was impaired in hidden platform learning in the Morris water maze on acquisition. They also showed reduced memory performance on probe trials. Similar trends were seen on reversal learning and reversal probe trials. Reduced platform-size learning trials caused spatial learning impairments to re-emerge in the MA40-4 group. The MA40-2 group showed no differences in straight channel swimming, but was slower at finding the visible platform during cued learning. They were also impaired during acquisition and memory trials in the Morris hidden platform maze. They showed a similar trend on reversal learning and memory trials, but were not different during reduced platform-size learning trials. When the MA40-2 group's performance on hidden platform learning and memory trials was adjusted for cued trial performance, the spatial learning deficits remained. Deficits of spatial learning and memory are a selective effect of neonatal methamphetamine treatment irrespective of other learning and performance variables.

Aging↗
PubMed2000

Dorsal hippocampal function in unreinforced spatial learning.

This study examined learning about the spatial environment by rats during a single 10 min period of exploration on an eight-arm radial maze. Because no specific behaviors were learned during this procedure, the existence of learned spatial information was inferred from its retarding effect on subsequent conditioned cue preference (CCP) learning on the same maze. Previous experiments have shown that this form of spatial learning, measured in this way, requires an intact fimbriafornix and functional N-methyl-D-aspartate receptors. However, in the present experiments, large neurotoxic lesions of the dorsal hippocampus that impaired win-shift learning failed to eliminate the retarding effect of exploration on CCP learning. This result was obtained in three independent replications. These findings fail to confirm the hypothesis that the hippocampus is involved in spatial learning when that learning occurs in the absence of reinforcers and does not produce any specific learned behaviors. Previous work showed that this form of "pure" spatial learning requires an intact fimbria-fornix for acquisition but not for expression; the present findings suggest that the hippocampus is not required for either of these processes. The fimbria-fornix may interact with other temporal lobe structures in mediating this form of learning. The function of the hippocampus may be limited in some way to situations that involve reinforcers and/or situations in which specific behaviors are learned.

Animals↗
PubMed1993

Modification of the responses of hippocampal neurons in the monkey during the learning of a conditional spatial response task.

In order to analyze the function of the hippocampus in learning, the activity of single neurons was recorded while monkeys learned a task of the type known to be impaired by damage to the hippocampus. In the conditional response task, the monkey had to learn to make one response when one stimulus was shown, and a different response when a different stimulus was shown. It had previously been shown that there are neurons in the hippocampal formation that respond in this task, to, for example, a combination of a particular visual stimulus that had been associated in previous learning with a particular behavioral response. In the present study, it was found that during such conditional response learning, the activity of 22% of the neurons in the hippocampus and parahippocampal gyrus with activity specifically related to the task altered their responses so that their activity, which was initially equal to the two new stimuli, became progressively differential to the two stimuli when the monkey learned to make different responses to the two stimuli. These changes occurred for different neurons just before, at, or just after the time when the monkey learned the correct response to make to the stimuli. In addition to these neurons, which had differential responses that were sustained for as long as the recordings continued, another population of neurons (45% of those with activity specifically related to the task) developed differential activity to the two new stimuli, yet showed such differential responses transiently for only a small number of trials at about the time when the monkey learned. These findings are consistent with the hypothesis that some synapses on hippocampal neurons modify during this type of learning so that some neurons come to respond to particular stimulus-response associations that are being learned. Further, the finding that many hippocampal neurons started to reflect the new learning, but then stopped responding differentially (the transient neurons), is consistent with the hypothesis that the hippocampal neurons with large sustained changes in their activity inhibited the transient neurons, which then underwent reverse learning, thus providing a competitive mechanism by which not all neurons are allocated to any one learned association or event.

Action Potentials↗
PubMed1996

Inactivation of hippocampus or caudate nucleus with lidocaine differentially affects expression of place and response learning.

Involvement of the hippocampus and caudate nucleus in place and response learning was examined by functionally inactivating these brain regions bilaterally with infusions of lidocaine. Rats were trained to approach a consistently baited arm in a cross-maze from the same start box (four trials/day/14 total days). On Days 8 and 16 a single probe trial was given, in which rats were placed in the start box opposite that used in training and allowed to approach a maze arm. Three minutes prior to the probe trial, rats received bilateral injections of either saline or a 2% lidocaine solution (in order to produce neural inactivation) into either the dorsal hippocampus or dorsolateral caudate nucleus. On the probe trials, rats which entered the baited maze arm (i.e., approached the place where food was located during training) were designated place learners, and rats which entered the unbaited maze arm (i.e., made the same turning response as during training) were designated response learners. Saline-treated rats displayed place learning on the Day 8 probe trial and response learning on the Day 16 probe trial, indicating that with extended training there is a shift in learning mechanisms controlling behavior. Rats given lidocaine injections into the hippocampus showed no preference for place or response learning on the Day 8 probe trial, but displayed response learning on the Day 16 probe trial, indicating a blockade of place learning following inactivation of the hippocampus. Rats given lidocaine injections into the caudate nucleus displayed place learning on both the Day 8 and the Day 16 probe trials, indicating a blockade of response learning following inactivation of the caudate nucleus. The findings indicate: (1) the hippocampus and caudate nucleus selectively mediate expression of place and response learning, respectively (2), in a visually cued extramaze environment, hippocampal-dependent place learning is acquired faster than caudate-dependent response learning, and (3) when animals shift to caudate-dependent response learning with extended training, the hippocampal-based place representation remains intact.

Anesthetics↗
PubMed1993

Effects of intracranial infusions of chlordiazepoxide on spatial learning in the Morris water maze. II. Neuropharmacological specificity.

In the preceding paper it was found that infusions of chlordiazepoxide (CDP) into the medial septal region, but not several other regions possessing a high density of benzodiazepine receptors, impaired spatial learning, but not cue learning or swim speed, in the Morris water maze. The present investigation sought to further characterize the neuropharmacological profile of this effect. Initially, it was reconfirmed that systemically administered CDP impaired spatial learning, but not cue learning or swim speed, in the water maze. Additionally, it was found that systemically administered scopolamine, a muscarinic antagonist, impaired both spatial and cue learning, but not swim speed, confirming the detrimental effects of cholinergic hypofunction on maze learning. In new rats, a dose-response assessment revealed that 60 and 30 nmol, but not 10 nmol, CDP infused into the medial septum impaired spatial learning, but not cue learning or swim speed. On the following day, rats from each dose group, now undrugged, acquired a reversed platform location at control levels, suggesting that the previously observed impairment was not due to a neurotoxic effect. Additionally, it was found that systemically administered flumazenil (10 mg/kg) blocked the spatial learning deficit produced by the 60 nmol dose of CDP infused into the medial septum. However, intraseptal infusions of flumazenil (10, 20, or 30 nmol) failed to attenuate the spatial learning deficit produced by systemically administered CDP. Finally, systemically administered tetrahydroaminoacridine (1 or 3 mg/kg), an acetylcholinesterase inhibitor, failed to attenuate the spatial learning deficit produced by intraseptal CDP (60 nmol). Together these results implicate benzodiazepine receptors in the medial septum in the amnesic actions of CDP but suggest that additional sites also mediate this action. The present results fail to support the idea that the spatial learning deficit produced by intraseptal infusions of CDP is due to a suppression of septo-hippocampal cholinergic activity and it is proposed that CDP impairs spatial learning by exacerbating hippocampal inhibition by inhibiting septo-hippocampal GABAergic projection neurons.

Animals↗
PubMed2006

Evaluation of the errorless learning technique in children with traumatic brain injury.

OBJECTIVE: To compare errorless learning with trial-and-error (T&E) learning of declarative facts in children with memory disorders secondary to traumatic brain injury (TBI). DESIGN: Retrospective within-subjects concurrent treatment design. SETTING: Participants' school or home. PARTICIPANTS: Thirty-four children, ages 6 to 18 years, with mild, moderate, or severe postacute TBI who met criteria for memory impairment. INTERVENTION: Conditions consisted of an errorless learning method and a T&E method. Within a session, half the items were taught with the errorless learning method and half with the T&E method. Each child received two 1-hour sessions a week for 7 weeks. MAIN OUTCOME MEASURES: Relative effectiveness of errorless learning and T&E methods for (1) initial learning and (2) retention over time for learned items. RESULTS: There was an advantage for T&E on initial learning. In children with mild, but not moderate or severe TBI, 2-day retention was better with the errorless learning technique; 7-day retention was better with errorless learning in young children with mild TBI. Seventy-seven-day retention revealed an advantage for errorless learning in younger children with severe TBI. CONCLUSIONS: Findings did not support errorless learning as a generalized intervention for learning difficulties after TBI or identify specific age- or injury-severity groups that benefited from this technique.

Adolescent↗
PubMed2006

The striatum and probabilistic implicit sequence learning.

The distinction between implicit (unconscious) and explicit (conscious) learning is controversial. Some argue that explicit learning is dependent on the medial temporal lobes, whereas implicit learning is mediated by the basal ganglia and others propose that all learning is explicit. The purpose of the present study was to investigate the involvement of the basal ganglia in implicit learning by examining learning of a probabilistic sequence of targets, in patients with Parkinson's disease (PD) and controls. Following learning, we assessed participants' awareness of the sequence structure by asking them to generate or withhold sequence consistent responses (process dissociation procedure) and to perform a recognition test in which measures of priming and recognition were obtained concurrently. Although the PD group demonstrated evidence of probabilistic sequence learning in this study, learning was significantly attenuated compared to controls. Residual learning in the PD group was genuinely implicit in nature because (a) PD patients were not able to control the expression of their acquired knowledge, and (b) their knowledge supported subsequent priming of sequence-consistent responses but recognition ratings were at chance. In contrast, following learning controls were capable of above chance recognition indicating that their sequential knowledge was acquired in a more explicit way. The results support the view that (i) the basal ganglia contribute to probabilistic implicit sequence learning (ii) that such learning can occur implicitly without explicit knowledge in PD patients.

Aged↗
PubMed2000

Student nurses' lived experience of preceptorship. Part 1--in relation to learning.

In this first part of a research project a phenomenological approach was applied to understanding student nurses' experience of preceptorship. The lived experience of seventeen student nurses learning within a preceptor-preceptee relationship on hospital wards formed the basis of the study. Tape-recorded interviews were conducted, transcribed and analysed. The phenomenological hermeneutic analysis revealed three themes of meaning central to the lived experience of learning. These were (a) directing learning; (b) learning in practical action and (c) feeling in learning. The themes included six sub-themes with internal variations. The results indicate that learning, as a phenomenon, could be understood as being in different modes of learning, including directing learning, learning in practical actions and feeling in learning. Each theme was also found to be inherent in the others in an ongoing changeable process. The findings were compared with Aristotle's five modes of learning and revealed that the student nurses' learning embraced scientific knowledge, technical skills, practical wisdom and limited intuition. The study may provide nurse educators with some insight into student nurses' learning by being in real-life situations and performing nursing actions within a preceptor-preceptee relationship.

Adult↗
PubMed2001

Could the 5-HT1B receptor inverse agonism affect learning consolidation?

Diverse evidence indicates that, the 5-HT system might play a role in learning and memory, since it occurs in brain areas mediating such processes and 5-HT drugs modulate them. Hence in this work, in order to explore further 5-HT involvement on learning and memory 5-HT1B receptors' role is investigated. Evidence indicates that SB-224289 (a 5-HT1B receptor inverse agonist) post-training injection facilitated learning consolidation in an associative autoshaping learning task, this effect was partially reversed by GR 127935 (a 5-HT1B/1D receptor antagonist), but unaffected by MDL 100907 (a 5-HT2A receptor antagonist) or ketanserin (a 5-HT1D/2A/7 receptor antagonist) at low doses. Moreover, SB-224289 antagonized the learning deficit produced by TFMPP (a 5-HT1A/1B/1D/2A/2C receptor agonist), GR 46611 (a 5-HT1A/1B/1D receptor agonist), mCPP (a 5-HT2A/2C/3/7 receptor agonist/antagonist) or GR 127935 (at low dose). SB-224289 did not alter the 8-OH-DPAT (a 5-HT1A/7 receptor agonist) learning facilitatory effect. SB-224289 eliminated the deficit learning produced by the anticholinergic muscarinic scopolamine or the glutamatergic antagonist dizocilpine. Administration of both, GR 127935 (5mg/kg) plus ketanserin (0.01 mg/kg) did not modify learning consolidation; nevertheless, when ketanserin dose was increased (0.1-1.0mg/kg) and SB-224289 dose was maintained constant, a learning facilitation effect was observed. Notably, SB-224289 at 1.0mg/kg potentiated a subeffective dose of the 5-HT1B/1D receptor agonist/antagonist mixed GR 127935, which facilitated learning consolidation and this effect was abolished by ketanserin at a higher dose. Collectively, the data confirm and extend the earlier findings with GR 127935 and the effects of non-selective 5-HT(1B) receptor agonists. Clearly 5-HT1B agonists induced a learning deficit which can be reversed with SB-224289. Perhaps more importantly, SB-224289 enhances learning consolidation when given alone and can reverse the deficits induced by both cholinergic and glutamatergic antagonist. Hence, 5-HT1B receptor inverse agonists or antagonists could represent drugs for the treatment of learning and memory dysfunctions.

Child↗
PubMed1999

A neural network model with dopamine-like reinforcement signal that learns a spatial delayed response task.

This study investigated how the simulated response of dopamine neurons to reward-related stimuli could be used as reinforcement signal for learning a spatial delayed response task. Spatial delayed response tasks assess the functions of frontal cortex and basal ganglia in short-term memory, movement preparation and expectation of environmental events. In these tasks, a stimulus appears for a short period at a particular location, and after a delay the subject moves to the location indicated. Dopamine neurons are activated by unpredicted rewards and reward-predicting stimuli, are not influenced by fully predicted rewards, and are depressed by omitted rewards. Thus, they appear to report an error in the prediction of reward, which is the crucial reinforcement term in formal learning theories. Theoretical studies on reinforcement learning have shown that signals similar to dopamine responses can be used as effective teaching signals for learning. A neural network model implementing the temporal difference algorithm was trained to perform a simulated spatial delayed response task. The reinforcement signal was modeled according to the basic characteristics of dopamine responses to novel stimuli, primary rewards and reward-predicting stimuli. A Critic component analogous to dopamine neurons computed a temporal error in the prediction of reinforcement and emitted this signal to an Actor component which mediated the behavioral output. The spatial delayed response task was learned via two subtasks introducing spatial choices and temporal delays, in the same manner as monkeys in the laboratory. In all three tasks, the reinforcement signal of the Critic developed in a similar manner to the responses of natural dopamine neurons in comparable learning situations, and the learning curves of the Actor replicated the progress of learning observed in the animals. Several manipulations demonstrated further the efficacy of the particular characteristics of the dopamine-like reinforcement signal. Omission of reward induced a phasic reduction of the reinforcement signal at the time of the reward and led to extinction of learned actions. A reinforcement signal without prediction error resulted in impaired learning because of perseverative errors. Loss of learned behavior was seen with sustained reductions of the reinforcement signal, a situation in general comparable to the loss of dopamine innervation in Parkinsonian patients and experimentally lesioned animals. The striking similarities in teaching signals and learning behavior between the computational and biological results suggest that dopamine-like reward responses may serve as effective teaching signals for learning behavioral tasks that are typical for primate cognitive behavior, such as spatial delayed responding.

Animals↗
PubMedDate not supplied

A neural model of cortico-cerebellar interactions during attentive imitation and predictive learning of sequential handwriting movements.

Much sensory-motor behavior develops through imitation, as during the learning of handwriting by children. Such complex sequential acts are broken down into distinct motor control synergies, or muscle groups, whose activities overlap in time to generate continuous, curved movements that obey an inverse relation between curvature and speed. How are such complex movements learned through attentive imitation? Novel movements may be made as a series of distinct segments, but a practiced movement can be made smoothly, with a continuous, often bell-shaped, velocity profile. How does learning of complex movements transform reactive imitation into predictive, automatic performance? A neural model is developed which suggests how parietal and motor cortical mechanisms, such as difference vector encoding, interact with adaptively timed, predictive cerebellar learning during movement imitation and predictive performance. To initiate movement, visual attention shifts along the shape to be imitated and generates vector movement using motor cortical cells. During such an imitative movement, cerebellar Purkinje cells with a spectrum of delayed response profiles sample and learn the changing directional information and, in turn, send that learned information back to the cortex and eventually to the muscle synergies involved. If the imitative movement deviates from an attentional focus around a shape to be imitated, the visual system shifts attention, and may make an eye movement, back to the shape, thereby providing corrective directional information to the arm movement system. This imitative movement cycle repeats until the cortico-cerebellar system can accurately drive the movement based on memory alone. A cortical working memory buffer transiently stores the cerebellar output and releases it at a variable rate, allowing speed scaling of learned movements which is limited by the rate of cerebellar memory readout. Movements can be learned at variable speeds if the density of the spectrum of delayed cellular responses in the cerebellum varies with speed. Learning at slower speeds facilitates learning at faster speeds. Size can be varied after learning while keeping the movement duration constant (isochrony). Context-effects arise from the overlap of cerebellar memory outputs. The model is used to simulate key psychophysical and neural data about learning to make curved movements, including a decrease in writing time as learning progresses; generation of unimodal, bell-shaped velocity profiles for each movement synergy; size and speed scaling with preservation of the letter shape and the shapes of the velocity profiles; an inverse relation between curvature and tangential velocity; and a Two-Thirds Power Law relation between angular velocity and curvature.

Attention↗
PubMed2004

Neocognitron capable of incremental learning.

This paper proposes a new neocognitron that accepts incremental learning, without giving a severe damage to old memories or reducing learning speed. The new neocognitron uses a competitive learning, and the learning of all stages of the hierarchical network progresses simultaneously. To increase the learning speed, conventional neocognitrons of recent versions sacrificed the ability of incremental learning, and used a technique of sequential construction of layers, by which the learning of a layer started after the learning of the preceding layers had completely finished. If the learning speed is simply set high for the conventional neocognitron, simultaneous construction of layers produces many garbage cells, which become always silent after having finished the learning. The proposed neocognitron with a new learning method can prevent the generation of such garbage cells even with a high learning speed, allowing incremental learning.

Cognition↗
PubMed2004

Orienting teaching toward the learning process.

Based on developments in educational psychology from the late 1980s, the authors present a model of an approach to teaching. Students' learning processes were analyzed to determine teacher functions. The learning-oriented teaching (LOT) model aims at following and guiding the learning process. The main characteristics of the model are (1) the components of learning: cognition (what to learn), affect (why learn), and metacognition (how to learn); and (2) the amount of guidance students need. If education aims at fostering one's ability to function independently in society, an important general objective should be that one learns how to fully and independently regulate his or her own learning; i.e., the ability to pursue one's professional life independently. This implies a transition from external guidance (from the teacher) through shared guidance (by the student together with the teacher) to internal guidance (by the student alone). This transition pertains not only to the cognitive component of learning (content) but also to the affective component (motives) and the metacognitive component (learning strategies). This model reflects a philosophy of internalization of the teacher's functions in a way that allows optimal independent learning after graduation. The model can be shown as a two-dimensional chart of learning components versus levels of guidance. It is further elaborated from learners' and teachers' perspectives. Examples of curriculum structure and teachers' activities are given to illustrate the model. Implications for curriculum development, course development, individual teaching moments, and educational research are discussed.

Cognition↗
PubMed2007

Medical students' learning of anatomy: memorisation, understanding and visualisation.

INTRODUCTION: There is much subjective discussion, but few empirical data that explore how students approach the learning of anatomy. AIMS: Students' perceptions of successful approaches to learning anatomy were correlated with their own approaches to learning, quality of learning and grades. METHODS: First-year medical students (n = 97) studying anatomy at an Australian university completed an online survey including a version of the Study Process Questionnaire (SPQ) that measures approaches to learning. The quality of students' written assessment was rated using the Structure of Observed Learning Outcomes (SOLO) taxonomy. Final examination data were used for correlation with approaches and quality of learning. RESULTS: Students perceived successful learning of anatomy as hard work, involving various combinations of memorisation, understanding and visualisation. Students' surface approach (SA) scores (mean 30 +/- 3.4) and deep approach (DA) scores (mean 31 +/- 4.2) reflected the use of both memorisation and understanding as key learning strategies in anatomy. There were significant correlations between SOLO ratings and DA scores (r = 0.24, P < 0.01), between SA scores and final grades (r = - 0.30, P < 0.01) and between SOLO ratings and final grades (r = 0.61, P < 0.01) in the subject. CONCLUSIONS: Approaches to learning correlate positively with the quality of learning. Successful learning of anatomy requires a balance between memorisation with understanding and visualisation. Interrelationships between these three strategies for learning anatomy in medicine and other disciplines require further investigation.

Anatomy↗
PubMed2002

Postal survey of approaches to learning among Ontario physicians: implications for continuing medical education.

OBJECTIVES: To understand the approaches to learning of practising physicians in their workplace and to assess the relation of these approaches to their motivation for, preferred methods of, and perceived barriers to continuing medical education. DESIGN: Postal survey of 800 Ontario physicians. PARTICIPANTS: 373 physicians who responded. MAIN OUTCOME MEASURES: Correlations of approaches to learning and perceptions of workplace climate with methods, motives, and barriers to continuing medical education. RESULTS: Perceived heavy workload was significantly associated with the surface disorganised (r=0.463, P<0.01) and surface rational approach (r=0.135, P<0.05) to learning. The deep approach to learning was significantly correlated with a perception of choice-independence and a supportive-receptive climate at work (r=0.341 and 0.237, P<0.01). Physicians who adopt a deep approach to learning seem to be internally motivated to learn, whereas external motivation is associated with surface approaches to learning. Heavy workload and a surface disorganised approach to learning were correlated with every listed barrier to continuing medical education. The deep approach to learning was associated with independent learning activities and no barriers. CONCLUSIONS: Perception of the workplace climate affects physicians' approaches to learning at work and their motivation for and perceived barriers to continuing medical education. Younger, rural, family physicians may be most vulnerable to feeling overworked and adopting less effective approaches to learning. Further work is required to determine if changing the workplace environment will help physicians learn more effectively.

Attitude of Health Personnel↗
PubMed1998

Neuronal activity in medial frontal cortex during learning of sequential procedures.

To study the role of medial frontal cortex in learning and memory of sequential procedures, we examined neuronal activity of the presupplementary motor area (pre-SMA) and supplementary motor area (SMA) while monkeys (n = 2) performed a sequential button press task, "2 x 5 task." In this paradigm, 2 of 16 (4 x 4 matrix) light-emitting diode buttons (called "set") were illuminated simultaneously and the monkey had to press them in a predetermined order. A total of five sets (called "hyperset") was presented in a fixed order for completion of a trial. We examined the neuronal activity of each cell using two kinds of hypersets: new hypersets that the monkey experienced for the first time for which he had to find the correct orders of button presses by trial-and-error and learned hypersets that the monkey had learned with extensive practice (n = 16 and 10 for each monkey). To investigate whether cells in medial frontal cortex are involved in the acquisition of new sequences or execution of well-learned procedures, we examined three to five new hypersets and three to five learned hypersets for each cell. Among 345 task-related cells, we found 78 cells that were more active during performance of new hypersets than learned hypersets (new-preferring cells) and 18 cells that were more active for learned hypersets (learned-preferring cells). Among new-preferring cells, 33 cells showed a learning-dependent decrease of cell activity: their activity was highest at the beginning of learning and decreased as the animal acquired the correct response for each set with increasing reliability. In contrast, 11 learned-preferring cells showed a learning-dependent increase of neuronal activity. We found a difference in the anatomic distribution of new-preferring cells. The proportion of new-preferring cells was greater in the rostral part of the medial frontal cortex, corresponding to the pre-SMA, than the posterior part, the SMA. There was some trend that learned-preferring cells were more abundant in the SMA. These results suggest that the pre-SMA, rather than SMA, is more involved in the acquisition of new sequential procedures.

Animals↗
PubMed2004

Perceptual learning through optimization of attentional weighting: human versus optimal Bayesian learner.

Human performance in visual detection, discrimination, identification, and search tasks typically improves with practice. Psychophysical studies suggest that perceptual learning is mediated by an enhancement in the coding of the signal, and physiological studies suggest that it might be related to the plasticity in the weighting or selection of sensory units coding task relevant information (learning through attention optimization). We propose an experimental paradigm (optimal perceptual learning paradigm) to systematically study the dynamics of perceptual learning in humans by allowing comparisons to that of an optimal Bayesian algorithm and a number of suboptimal learning models. We measured improvement in human localization (eight-alternative forced-choice with feedback) performance of a target randomly sampled from four elongated Gaussian targets with different orientations and polarities and kept as a target for a block of four trials. The results suggest that the human perceptual learning can occur within a lapse of four trials (<1 min) but that human learning is slower and incomplete with respect to the optimal algorithm (23.3% reduction in human efficiency from the 1st-to-4th learning trials). The greatest improvement in human performance, occurring from the 1st-to-2nd learning trial, was also present in the optimal observer, and, thus reflects a property inherent to the visual task and not a property particular to the human perceptual learning mechanism. One notable source of human inefficiency is that, unlike the ideal observer, human learning relies more heavily on previous decisions than on the provided feedback, resulting in no human learning on trials following a previous incorrect localization decision. Finally, the proposed theory and paradigm provide a flexible framework for future studies to evaluate the optimality of human learning of other visual cues and/or sensory modalities.

Adult↗
PubMed1999

An open, nonrandomized clinical comparative study evaluating the effect of epilepsy on learning.

Children with epilepsy, as a group, have a greater risk for developing learning problems as comorbid disorders. It is unknown which factors contribute to the development of such learning problems; therefore, our current knowledge does not allow the prediction of educational delay in an individual child with epilepsy. This study aimed at excluding as many factors as possible that could interfere with the analysis of the impact of epilepsy on learning. From patients referred to us in 1997 (N = 123), children were included with mild global learning impairment, defined as educational delay between 6 months and 1 year and no other apparent reason for learning impairment except for epilepsy (ie, excluding children with dyslexia, attention-deficit hyperactivity disorder, or mental handicap). A total of 44 patients fulfilled this criterion: 31 also had epilepsy (experimental group); the remaining 13 patients with similar mild learning impairment but without epilepsy were used as controls. In the experimental group two subgroups were distinguished on the basis of onset of learning impairment: in group A (n = 17) the learning problems are not unexpected as they were preceded by mild developmental delay; in group B (n = 14) the problems are unexpected and had a sudden onset. The two experimental groups differed from the control group on a number of variables, such as gender and the incidence of perinatal complications. More differences have been found between the two experimental groups: group B is selected from a larger group: all children with mild global learning impairment with sudden onset. In this group considerably more children with epilepsy have been found compared to the children with developmental delay; moreover the epilepsy is more often characterized in these children as "unexpected," that is, there was no previous established diagnosis of epilepsy, the symptoms were mostly unclear and behavioral in make-up (attentional lapses, etc); the electroencephalogram plays a much greater role in the diagnosis in this group, especially in demonstrating seizures; finally, the children in this group more frequently have neuropsychologic impairment. Children with epilepsy can have mild global learning difficulties, especially in the period after the onset of seizures. This group can be divided in a group with "trait-dependent learning difficulties," that is learning difficulties based on developmental delay, and a group with "state-dependent learning difficulties." The focus in our study was on this latter group, consisting of children with sudden and unexpected decline of results in school. The crucial finding in this group is the relatively frequent demonstration of difficult-to-detect seizures, demonstrating that an uncontrolled epilepsy can cause a decline in school results even when the seizures are of short duration and have subtle symptoms.

Attention Deficit Disorder with Hyperactivity↗