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Dynamic cortical involvement in implicit and explicit motor sequence learning. A PET study.
We examined the dynamic involvement of different brain regions in implicit and explicit motor sequence learning using PET. In a serial reaction time task, subjects pressed each of four buttons with a different finger of the right hand in response to a visually presented number. Test sessions consisted of 10 cycles of the same 10-item sequence. The effects of explicit and implicit learning were assessed separately using a different behavioural parameter for each type of learning: correct recall of the test sequence for explicit learning and improvement of reaction time before the successful recall of any component of the test sequence for implicit learning. Regional cerebral blood flow was measured repeatedly during the task, and a parametric analysis was performed to identify brain regions in which activity was significantly correlated with subjects' performances: i.e. with correct recall of the test sequence or with reaction time. Explicit learning, shown as a positive correlation with the correct recall of the sequence, was associated with increased activity in the posterior parietal cortex, precuneus and premotor cortex bilaterally, also in the supplementary motor area (SMA) predominantly in the left anterior part, left thalamus, and right dorsolateral prefrontal cortex. In contrast, the reaction time showed a different pattern of correlation during different learning phases. During the implicit learning phase, when the subjects were not aware of the sequence, improvement of the reaction time was associated with increased activity in the contralateral primary sensorimotor cortex (SM1). During the explicit learning phase, the reaction time was significantly correlated with activity in a part of the frontoparietal network. During the post-learning phase, when the subjects achieved all components of the sequence explicitly, the reaction time was correlated with the activity in the ipsilateral SM1 and posterior part of the SMA. These results show that different sets of cortical regions are dynamically involved in implicit and explicit motor sequence learning.
Adult↗
The birth of words: ten-month-olds learn words through perceptual salience.
A core task in language acquisition is mapping words onto objects, actions, and events. Two studies investigated how children learn to map novel labels onto novel objects. Study 1 investigated whether 10-month-olds use both perceptual and social cues to learn a word. Study 2, a control study, tested whether infants paired the label with a particular spatial location rather than to an object. Results show that 10-month-olds can learn new labels and do so by relying on the perceptual salience of an object instead of social cues provided by a speaker. This is in direct contrast to the way in which older children (12-, 18-, and 24-month-olds) learn and extend new object names.
Child Development↗
Dual-modality impairment of implicit learning of letter-strings versus color-patterns in patients with schizophrenia.
BACKGROUND: Implicit learning was reported to be intact in schizophrenia using artificial grammar learning. However, emerging evidence indicates that artificial grammar learning is not a unitary process. The authors used dual coding stimuli and schizophrenia clinical symptom dimensions to re-evaluate the effect of schizophrenia on various components of artificial grammar learning. METHODS: Letter string and color pattern artificial grammar learning performances were compared between 63 schizophrenic patients and 27 comparison subjects. Four symptom dimensions derived from a Chinese Positive and Negative Symptom Scale ratings were correlated with patients' artificial grammar implicit learning performances along the two stimulus dimensions. Patients' explicit memory performances were assessed by verbal paired associates and visual reproduction subtests of the Wechsler Memory Scales Revised Version to provide a contrast to their implicit memory function. RESULTS: Schizophrenia severely hindered color pattern artificial grammar learning while the disease affected lexical string artificial grammar learning to a lesser degree after correcting the influences from age, education and the performance of explicit memory function of both verbal and visual modalities. Both learning performances correlated significantly with the severity of patients' schizophrenic clinical symptom dimensions that reflect poor abstract thinking, disorganized thinking, and stereotyped thinking. CONCLUSION: The results of this study suggested that schizophrenia affects various mechanisms of artificial grammar learning differently. Implicit learning, knowledge acquisition in the absence of conscious awareness, is not entirely intact in patients with schizophrenia. Schizophrenia affects implicit learning through an impairment of the ability of making abstractions from rules and at least in part decreasing the capacity for perceptual learning.
Journal Article↗
Nicotine administration enhances conditioned inhibition in rats.
The effect of nicotine on conditioned inhibition was examined using a serial feature negative discrimination task. Nicotine (0.35 mg/kg) or vehicle was administered before each of the 16 training sessions. On some trials in each session, a tone was presented and followed by food reward. On other trials, the tone was preceded by a visual stimulus and not reinforced. Nicotine-treated rats exhibited greater discrimination between the two trial types as evidenced by less frequent responding during non-reinforced trials, and learned the discrimination in fewer sessions than vehicle-treated rats. In contrast, there were no group differences in responding during the reinforced trials.
Analysis of Variance↗
Procedural learning and neostriatal dysfunction in man.
Patients with early stage Parkinson's disease are shown to be selectively impaired in a cognitive task of procedural learning while remaining intact in recall and recognition tests of declarative memory. In contrast, amnestic patients showed the opposite set of deficits, thus demonstrating a double dissociation. Patients with early Huntington's disease were either comparable to the parkinsonian patients or to amnestics. In the advanced Huntington's group, both procedural learning and declarative memory were impaired. It is argued that cognitive procedural learning depends on the establishment of heuristic strategies through the action of a circuit which involves the neostriatum and the prefrontal cortex.
Adult↗
Neuropsychological deficits in neuroleptic naive patients with first-episode schizophrenia.
BACKGROUND: Medication and chronicity have complicated past attempts to characterize the neuropsychological performance of patients with schizophrenia. There have been inconsistencies regarding the pattern, selectivity, and sources of observed deficits. Our objective was to comprehensively examine neuropsychological function in patients with schizophrenia who had never been exposed to neuroleptic medication, and who were experiencing their first episode (FE) of psychosis. METHODS: Subjects were consecutive recruitments that included 37 patients with FE schizophrenia who were never exposed to neuroleptics. These subjects were compared with 65 unmedicated, previously treated (PT) patients and 131 healthy controls. RESULTS: The patients groups had nearly identical profiles showing generalized impairment, particularly in verbal memory and learning, attention-vigilance, and speeded visual-motor processing and attention. Verbal memory and learning accounted for most of the variance between patients and controls and removing this effect substantially attenuated all other differences. By contrast, both the FE group and PT group continued to show highly significant deficits in verbal memory and learning after controlling for attention, abstraction, and all other functions. Some functions not typically implicated in schizophrenia (spatial cognition, fine motor speed, and visual memory) were more impaired in the PT group than in the FE group. CONCLUSIONS: Verbal memory, as a primary neuropsychological deficit present early in the course of schizophrenia, implicates the left temporal-hippocampal system. Neuropsychological evaluations before treatment permit differentiation of primary deficits from changes secondary to medication or chronicity. This is essential for developing a neurobehavioral perspective on schizophrenia.
Adult↗
Reading strategies and prior knowledge in learning from hypertext.
In two experiments, we identified two main strategies followed by hypertext readers in selecting their reading orders. The first consisted in selecting the text semantically related to the previously read section (coherence strategy), and the second in choosing the most interesting text, delaying reading of less interesting sections (interest strategy). Comprehension data revealed that these strategies affected learning differently as a function of the reader's prior knowledge. For low-knowledge readers, the coherence strategy supported better learning of the content. This effect seems to rely on the improvement of reading order coherence induced by this strategy. By contrast, for intermediate-knowledge readers the coherence and the interest strategies benefited comprehension equally. In both cases, learning was supported through the active processing induced by these strategies. Discussion focuses on resolving inconsistencies in the literature concerning whether or not hypertext supports better comprehension than does traditional linear texts.
Association Learning↗
The use of pigmentation and shading information in recognising the sex and identities of faces.
An investigation of what can be learned about representational processes in face recognition from the independent and combined effects of inverting and negating facial images is reported. In experiment 1, independent effects of inversion and negation were observed in a task of identifying famous faces. In experiments 2 through 4 the question of whether effects of negation were still obtained when effects due to the reversal of pigmentation in negative images were eliminated was examined. By the use of images of the 3-D surfaces of faces measured by laser, and displays as smooth surfaces devoid of pigmentation, only effects of inversion were obtained reliably, suggesting that the effects observed in experiment 1 arose largely through the inversion of pigmentation values in normal images of faces. The results of experiment 5 suggested that the difference was not due to the different task demands of experiments 2-4 compared with those of experiment 1. When normally pigmented face images were used in a task making similar demands to that of experiment 4, independent effects of inversion and negation were again observed. When a task of sex classification was used in experiments 6 and 7, clear effects of negation as well as inversion were observed on latencies, though not accuracies, of responding. The results are interpreted in terms of the information content of pigmentation relative to shape from shading in different face-classification tasks. The results also reinforce other recent evidence demonstrating the importance of image intensity as well as spatial layout of face 'features'.
Adult↗
Conditioning method dramatically alters the role of amygdala in taste aversion learning.
Although an important role for the amygdala in taste aversion learning has been suggested by work in a number of laboratories, results have been inconsistent and interpretations varied. The present series of studies reevaluated the role of the amygdala in taste aversion learning by examining the extent to which conditioning methods, testing methods and lesioning methods, influence whether amygdala lesions dramatically affect conditioned taste aversion (CTA) learning. Results indicated that when animals are conditioned with an intraoral (I/O) taste presentation, lesions of amygdala eliminate evidence of conditioning whether animals are tested intraorally or with a two-bottle solution presentation. Dramatic effects of amygdala lesions on CTA learning were seen whether lesions were made electrolytically or using an excitotoxin. In contrast, when animals were conditioned using bottle presentation of the taste, electrolytic lesions attenuated CTAs but did not eliminate them, and excitotoxic lesions had no effect. These results are consistent with the hypothesis that neural structures critical for CTA learning may differ depending on the extent to which the method of conditioned stimulus delivery incorporates a response component.
Amygdala↗
Temperament and personality.
Recent efforts to integrate psychometric and neurobiological data about personality have stimulated diverse interdisciplinary applications. The dissociation of major brain systems linked to procedural and propositional memory and learning has clarified the clinical distinction between two components of personality: temperament and character. Temperament can be defined in terms of individual differences in percept-based habits and skills (i.e. related to procedural memory and learning), which are regulated by the amygdala, hypothalamus, striatum, and other parts of the limbic system. In contrast, character can be defined in terms of individual differences in concept-based goals and values (i.e. related to propositional memory and learning), which are encoded by the hippocampal formation and cerebral neocortex. Recent descriptive, developmental, genetic, and neurobehavioral studies indicate that at least four dimensions of temperament and three dimensions of character can be uniquely described and functionally dissociated.
Animals↗
Spatial learning in male and female Long-Evans rats.
Male and female Long-Evans rats were tested in the Morris water maze at 6 months of age. A place training procedure, in which rats learned the position of a camouflaged platform, was followed by cue training, in which rats escaped to a visible platform. No sex difference was found in place learning ability. Search accuracy on probe trials, when the platform was unavailable, was also equivalent for the male and female groups. These results contrast with previous studies of rodents at younger ages, which have reported a male advantage in spatial learning. It is suggested that the age at which rats are assessed may be an important factor, possibly reflecting a different course in the relatively protracted maturation of the hippocampus in male and female rats. The results of this investigation are also discussed with reference to studies of sex differences for spatial abilities in humans.
Age Factors↗
Prior knowledge and functionally relevant features in concept learning.
Empirical learning models have typically focused on statistical aspects of features (e.g., cue and category validity). In general, these models do not address the contact between people's prior knowledge that lies outside the category and their experiences of the category. A variety of extensions to these models are examined, which combine prior knowledge with empirical learning. Predictions of these models were compared in 4 experiments. These studies contrasted the cue and category validity of features with people's prior knowledge about the relevance of features to the functions of novel artifacts. The findings suggest that the influences of knowledge and experience are more tightly integrated than some models would predict. Furthermore, relatively straightforward ways of incorporating knowledge into an empirical learning algorithm appear insufficient (e.g., use of knowledge to weight features by general relevance or to individually weight features). Other extensions to these models are suggested that focus on the importance of intermediary features, coherence, and conceptual roles.
Adult↗
Differences in classroom teaching preferences between traditional and adult BSN students.
The primary purposes of this study were to identify the best teaching practices for adult baccalaureate (BSN) nursing students and to examine if adult students' teaching preferences differed from those of traditional BSN students. The sample consisted of 206 adult and traditional students in four BSN programs. The adult nursing student sample was further subdivided into two groups: adults with no prior nursing education (adult non-nurses) and adults with prior nursing education (RN's). Using a two-part, self-administered questionnaire, respondents were asked to rate the frequency with which 41 teaching strategies were used in their best and in their worst classroom learning experiences in nursing. In most cases, adult non-nurses' teaching preferences did not vary significantly from the preferences of traditional students. However, adults with no prior nursing education did show a preference for knowledgeable and organized instructors. In contrast RNs' preferred classroom situations wer where time on task was emphasized, cooperative learning was encouraged, and expectations for learning were high. Results indicate that classroom teaching preferences vary as a function of prior experience with the subject matter and are not attributable to age itself. Findings suggest that prior experience with course content is a more important consideration in planning programs than generalized adult experience.
Adolescent↗
An electrophysiological study of errorless learning.
Errorless learning, i.e. learning under conditions that prevent the generation of false memory candidates, has been shown to lead to enhanced memory performance during retrieval compared to errorful, trial-and-error, learning. These two learning methods were implemented in a word-stem completion format and contrasted in young healthy subjects with stimulus-locked and response-locked event-related brain potentials (ERPs) being recorded during memory retrieval. Retrieval accuracy was enhanced for items studied under errorless conditions. Stimulus-locked ERPs showed a modulation of a right frontal effect that differed in amplitude and topography for items learned under errorful and errorless conditions. This effect is interpreted as reflecting post-retrieval processes. In the response-locked ERPs, a typical error-related negativity (ERN) was observed that was most prominent for false alarm trials in the errorless condition, of medium amplitude for hits and false alarms in the errorful condition, smaller for hits in the errorless condition and virtually absent for items correctly or incorrectly classified as new. We propose that the amplitude modulation of the ERN is related to the activity of an internal monitoring device checking the veridicality of a retrieved memory trace.
Adult↗
[Role of the implicit theories of intelligence in learning situations].
Most studies have tried to explain the school difficulties by analysing the intellectual factors that lead to school failure. However in addition to the instrumental capacities, authors also recognize the role played by other factors such as motivation. More specifically, the theory of achievement motivation aims to determine motivational factors involved in achievement situations when the students have to demonstrate their competencies. This paradigm attributes a central place to beliefs in order to explain children's behavior in academic situations. According to Dweck, it seems that beliefs about the nature of intelligence have a very powerful impact on behavior. These implicit theories of intelligence create a meaning system or conceptual framework that influences the individual interpretation of school situations. Thus, an entity theory of intelligence is the belief that intelligence is a fixed trait, a personal quality that cannot be changed. Students who subscribe to this theory believe that although people can learn new things, their underlying intelligence remains the same. In contrast, an incremental theory of intelligence is the belief that intelligence is a malleable quality that can increase through efforts. The identification of these two theories allows us to understand the cognition and behavior of individuals in achievement situations. Many studies carried out in the academic area show that students who hold an entity theory of intelligence (ie they consider intelligence like a stable quality) have a strong tendency to attribute their failures to a fixed trait. They are more likely to blame their intelligence for ne-gative outcomes and to attribute failures to their bad intellectual ability. In contrast, students who hold an incremental theory of intelligence (ie they consider intelligence as a malleable quality) are more likely to understand the same ne-gative outcomes in terms of specific factors: they attribute them to a lack of effort. This differential emphasis on traits versus specific mediators in turn fosters different reactions to negative events. Several studies have shown that entity theorists of intelligence are more likely than incremental theorists to react helplessly in the face of failure. They are not only more likely to make negative judgments about their intelligence from the failures, but also more likely to show negative affect and behaviors. This helpless response pattern is cha-racterized by a lack of persistence, and performance decrements. In contrast, incremental theorists, who focus more on behavioral factors (eg effort, problem-solving strategies) as causes of negative achievement outcomes, tend to act on these mediators. They try harder and develop better strategies and continue to work. Some authors have tendency to consider implicit theories of intelligence as a disposition or a stable dimension. But in the last few years, several studies showed that people's theories are not fixed traits; they are beliefs that may be influenced. These studies also suggested that students use the two types of beliefs and that the context determines the choice between the two types of theories. According to these authors, the psychological state of the student depends on dispositional factors but also on situational factors. Thus, several studies have tried to demonstrate that it is possible to modify experimentally implicit theories of intelligence and subsequent cognitions and behaviors by modifying situational factors. Several studies have demonstrated that it was possible to induce students to adopt one of the two theories of intelligence by presenting them a scientific article that compelling argued for either an entity or an incremental view of intelligence. The results showed that participants who had received the entity theory induction exhibited more evidence of a helpless reaction to failure. These studies show that some of the judgments and reactions associated with implicit theories can be experimentally induced by manipulating participant theories. However in the context of school difficulties, only few works have been conducted. We think that the model of the motivation of achievement would allow us to better understand maladjusted behaviors that engender failure and scholastic exclusion. In one study, reseachers have demonstrated that children with mental disorders are less likely than other children to hold an incremental theory of their intellectual abilities. Other studies have demonstrated that entity theorists interpret their bad results according to their global intelligence level by negatively judging their global abilities ("I think I am stupid"). It is interesting to note that these students make the same attributions as depressive students. These results reveal the need to determine systems of beliefs within populations with anxiety or depressive symptoms in order to characterise their motivational profiles. Indeed, we think that these symptoms contribute to modify implicit theories of intelligence and the nature of the subsequent scholastic achievement. Finally, we think that it is inte-resting to demonstrate the positive motivational effects of the experimental induction of the incremental theory. A series of studies showed that children's theories of intelligence expe-rimentally induced will influence their tendency to persevere in the face of failure. Like normally developing children, children with mental disorders were more likely to prefer challenging activities and report high levels of interest-enjoyment when the task was presented as one which is improvable. It suggests that although children with difficulties are pessimistic about improving their intellectual capacities, if a new task is introduced in a way that highlights the possibility of self-improvement (incremental theory), then they will pursue the challenge in an adaptive manner (strong perseverance, enjoy, and important interest). These results are very inte-resting. Indeed, highlighting an incremental theory had a po-sitive motivational effect on behavior in achievement situations. In addition, all these results also may open up several interesting perspectives for the treatment of learning disabi-lities. The results should lead to plan programmes of cognitive therapy in order to modify beliefs that underlie maladjusted achievement behaviors of children and adolescents in scholastic failure.
Achievement↗
Strain differences in activity and emotionality do not account for differences in learning and memory performance between C57BL/6 and DBA/2 mice.
This study examined emotionality, activity, learning and memory, as well as the influence of emotionality and activity on learning and memory performance in C57BL/6 and DBA/2 mice using a mouse-test battery. DBA/2 mice performed more poorly than C57BL/6 mice in complex learning tasks such as the water maze and object recognition tasks. In contrast, C57BL/ 6 mice showed attenuated habituation tonovelty in the open field apparatus and poorer performance in the step-down passive avoidance task. The C57BL/6 mice were less exploratory and more anxious than the DBA/ 2 mice. The anxiety score (open arm entries in the elevated plus maze) was significantly correlated with all measures of learning and memory in the object recognition task, and some measures in the passive avoidance and water maze tasks. Analysis of covariance (with open arm entries as a covariate) revealed that some measures on trial 1 of the object recognition task, but not the memory scores on trial 2,were confounded by anxiety. No confounding factors of anxiety were found in the water maze or passive avoidance tasks. Similar results were obtained with the activity scores (line crossing and rearing in the open field). In conclusion, strain differences in activity and anxiety did not account for strain differences in learning and memory performance of C57BL/6 and DBA/2 mice. Nonetheless, the importance of using complete behavioural test batteries should be stressed to ensure that strain differences in learning and memory tasks are not confounded by non-cognitive factors.
Animals↗
Scale-invariant superiority of foveal vision in perceptual categorization.
The recognition of objects is exceedingly difficult in indirect view. This complication cannot be explained in terms of retino-cortical magnification, as size scaling fails to establish position invariance both for character recognition [Strasburger, H. & Rentschler, I. (1996) Eur. J. Neurosci., 8 1787-1791] and pattern classification [Jüttner, M. & Rentschler, I. (1996) Vision Res., 36, 1007-1021]. Thus we compared, for two tasks of discrimination learning and category learning with respect to a common set of grey-level patterns, how humans perform in foveal and extrafoveal vision. Observers learnt to discriminate (size-scaled) images equally well in foveal and extrafoveal view, whereas they displayed profound deficiencies in extrafoveal category learning for the same patterns. From the behavioural learning data, internal representations of the learning signals were reconstructed by means of computer simulations. For foveal view, these representations were found to be veridical to their physical counterparts for both learning tasks. For extrafoveal view, they were severely distorted for category learning but not for discrimination learning. A variance reduction of the pattern classes by a factor of 100 reduced the dissociation between extrafoveal categorization and discrimination but did not remove it. These observations suggest a scale-invariant superiority of foveal vision for learning object categories. This implies a high degree of space variance of visual cognition which is vastly underestimated by classical measures of visual performance, e.g. acuity, visual field and contrast sensitivity.
Adult↗