Fast Mapping of Novel Word Forms Traced Neurophysiologically

Human capacity to quickly learn new words, critical for our ability to communicate using language, is well-known from behavioral studies and observations, but its neural underpinnings remain unclear. In this study, we have used event-related potentials to record brain activity to novel spoken word forms as they are being learnt by the human nervous system through passive auditory exposure. We found that the brain response dynamics change dramatically within the short (20 min) exposure session: as the subjects become familiarized with the novel word forms, the early (∼100 ms) fronto-central activity they elicit increases in magnitude and becomes similar to that of known real words. At the same time, acoustically similar real words used as control stimuli show a relatively stable response throughout the recording session; these differences between the stimulus groups are confirmed using both factorial and linear regression analyses. Furthermore, acoustically matched novel non-speech stimuli do not demonstrate similar response increase, suggesting neural specificity of this rapid learning phenomenon to linguistic stimuli. Left-lateralized perisylvian cortical networks appear to be underlying such fast mapping of novel word forms unto the brain’s mental lexicon

Physical exercise during encoding improves vocabulary learning in young female adults

Acute physical activity has been repeatedly shown to improve various cognitive functions. However, there have been no investigations comparing the effects of exercise during verbal encoding versus exercise prior to encoding on long-term memory performance. In this current psychoneuroendocrinological study we aim to test whether light to moderate ergometric bicycling during vocabulary encoding enhances subsequent recall compared to encoding during physical rest and encoding after being physically active. Furthermore, we examined the kinetics of brain-derived neurotrophic factor (BDNF) in serum which has been previously shown to correlate with learning performance. We also controlled for the BDNF val66met polymorphism. We found better vocabulary test performance for subjects that were physically active during the encoding phase compared to sedentary subjects. Post-hoc tests revealed that this effect was particularly present in initially low performers. BDNF in serum and BDNF genotype failed to account for the current result. Our data indicates that light to moderate simultaneous physical activity during encoding, but not prior to encoding, is beneficial for subsequent recall of new items

Neurology of foreign language aptitude

This state-of-the art paper focuses on the poorly explored issue of foreign language aptitude, attempting to present the latest developments in this field and reconceptualizations of the construct from the perspective of neuroscience. In accordance with this goal, it first discusses general directions in neurolinguistic research on foreign language aptitude, starting with the earliest attempts to define the neurological substrate for talent, sources of difficulties in the neurolinguistic research on foreign language aptitude and modern research methods. This is followed by the discussion of the research on the phonology of foreign language aptitude with emphasis on functional and structural studies as well as their consequences for the knowledge of the concept. The subsequent section presents the studies which focus on lexical and morphosyntactic aspects of foreign language aptitude. The paper ends with a discussion of the limitations of contemporary research, the future directions of such research and selected methodological issues

Word Learning in the Developing Brain : ERP Dynamics of Learning Word-Object Associations

This dissertation investigated electrophysiological measures of individual differences in toddlers’ ability to learn novel object labels and process familiar object words and their referents. The studies measured both visual and auditory event-related potentials (ERPs) in response to pictures of objects and words in a longitudinal sample of 20- to 24-month-olds, an age of dynamic vocabulary development. These ERP measures were related to the children’s productive vocabulary size as well as behavioral measures of word comprehension and object recognition.Study I aimed to test children’s ability to map familiar words to versions of their referents displaying reduced visual information (only overall shape or isolated parts), and whether this ability correlated with vocabulary size. Children with larger vocabularies showed a stronger N400 incongruity effect in response to words paired with correct vs. incorrect shape referents specifically, and the N400 effect in the shape condition also correlated with the children’s ability to overtly identify objects from their overall shape in a behavioral test. These results are discussed in relation to previous research demonstrating the emergence of a shape bias in children’s Word extension, as well as improvements in object shape recognition, during the second year of life.Study II investigated individual differences in novel word-object mapping andchanges with age in this ability. The overall sample showed ERP evidence of novel word learning (an N400 semantic incongruity effect) after five consistent word-object pairings at 24 months but not at 20 months. Children with large vocabularies demonstrated the same linear attenuation of N400 amplitude during novel word repetition as is commonly seen in adults, while children with smaller vocabularies did not show such attenuation until the end of the learning phase.Study III focused on the 20 month data set and explored how visual ERPs weremodulated as object-word pairs were presented repeatedly, and how these measures of visual object processing related to successful fast mapping of the novel words to the objects. A larger attenuation of the Nc component (associated with attention) predicted successful word learning, measured as a larger N400 incongruity effect to the novel words after training. Furthermore, better initial recognition of familiar objects correlated with a stronger N400 effect to the words for those objects. The results present novel evidence for a link between efficient visual processing of objects and word learning ability.Taken together, these findings demonstrate that the rapid vocabulary growth and striking individual differences in productive vocabulary development seen during children’s second year are linked to the dynamics of specific brain mechanisms involved in semantic processing of words and their referents

Depth of Encoding Through Observed Gestures in Foreign Language Word Learning

Word learning is basic to foreign language acquisition, however time consuming and not always successful. Empirical studies have shown that traditional (visual) word learning can be enhanced by gestures. The gesture benefit has been attributed to depth of encoding. Gestures can lead to depth of encoding because they trigger semantic processing and sensorimotor enrichment of the novel word. However, the neural underpinning of depth of encoding is still unclear. Here, we combined an fMRI and a behavioral study to investigate word encoding online. In the scanner, participants encoded 30 novel words of an artificial language created for experimental purposes and their translation into the subjects\u2019 native language. Participants encoded the words three times: visually, audiovisually, and by additionally observing semantically related gestures performed by an actress. Hemodynamic activity during word encoding revealed the recruitment of cortical areas involved in stimulus processing. In this study, depth of encoding can be spelt out in terms of sensorimotor brain networks that grow larger the more sensory modalities are linked to the novel word. Word retention outside the scanner documented a positive effect of gestures in a free recall test in the short term

Age related differences in feedback-based associative learning

Laine and Salmelin (2010) described language as dynamic, constantly changing as new words, expressions, and meanings appear and fade away. As a result, all speakers of a language, regardless of years of language use, must be able to update their lexicons to reflect these changes. Recently, there has been a growing literature exploring processes involved in new word learning across the lifespan suggesting that there are age-related differences on behavioral (Simon & Gluck, 2013) and neurofunctional (Cornelissen et al., 2003) levels. The present investigation explored these changes across decades of life, which, to the researcher’s knowledge, had not yet been done. In a picture-word verification task, the participants learned eight pairings of novel pictures and nonsense words using feedback provided throughout the task. Results revealed significant changes relating several dynamics of the study, including mastery decision time (DT), cumulative accuracy (ACC), and cumulative DT. In addition, the number of consecutive correct answers, as well as the total number of trials completed, revealed meaningful changes across the lifespan. With the following data, researchers were able to determine that there was a difference in decision time and accuracy in feedback-based associative learning across the lifespan. These data may influence programs designed to facilitate healthy cognitive aging in older adults, which would likely have an impact on overall quality of life. It might also benefit researchers developing future treatments of anomia to lessen signs of aphasia in those with the disorder

Electrophysiological and haemodynamic biomarkers of rapid acquisition of novel wordforms

Humans are unique in developing large lexicons; to achieve this, they are able to learn new words rapidly. However, the neural bases of this rapid learning, which may be an expression of a more general mechanism rooted in plasticity at cellular and synaptic levels, are not yet understood. Here, we highlight a selection of recent EEG and fMRI studies that attempted to trace word-learning in the human brain non-invasively. They show a rapid development of cortical memory traces for novel wordforms over a short session of auditory exposure to these items. Moreover, they demonstrate that this effect appears to be independent of attention, reflecting the largely automatic nature of word acquisition. At the same time, it seems to be limited to stimuli with native phonology, likely benefiting from pre-existing perception-articulation links in the brain, and thus suggesting different neural strategies for learning words in native and non-native languages. We also show a complex interplay between overnight consolidation, amount of exposure to novel vocabulary and attention to speech input, all of which influence learning outcomes. In sum, the available evidence suggests that the brain may effectively form new cortical circuits online, as it gets exposed to novel linguistic elements in the sensory input. A number of brain areas, most notably in the hippocampus and neocortex, appear to take part in word acquisition. Critically, the currently available data not only demonstrate a hippocampal role in rapid encoding followed by slow-rate consolidation of cortical memory traces, but also suggest immediate neocortical involvement in the word memory trace formation

Imaging short- and long-term training success in chronic aphasia

<p>Abstract</p> <p>Background</p> <p>To date, functional imaging studies of treatment-induced recovery from chronic aphasia only assessed short-term treatment effects after intensive language training. In the present study, we show with functional magnetic resonance imaging (fMRI), that different brain regions may be involved in immediate versus long-term success of intensive language training in chronic post-stroke aphasia patients.</p> <p>Results</p> <p>Eight patients were trained daily for three hours over a period of two weeks in naming of concrete objects. Prior to, immediately after, and eight months after training, patients overtly named trained and untrained objects during event-related fMRI. On average the patients improved from zero (at baseline) to 64.4% correct naming responses immediately after training, and treatment success remained highly stable at follow-up. Regression analyses showed that the degree of short-term treatment success was predicted by increased activity (compared to the pretraining scan) bilaterally in the hippocampal formation, the right precuneus and cingulate gyrus, and bilaterally in the fusiform gyri. A different picture emerged for long-term training success, which was best predicted by activity increases in the right-sided Wernicke's homologue and to a lesser degree in perilesional temporal areas.</p> <p>Conclusion</p> <p>The results show for the first time that treatment-induced language recovery in the chronic stage after stroke is a dynamic process. Initially, brain regions involved in memory encoding, attention, and multimodal integration mediated treatment success. In contrast, long-term treatment success was predicted mainly by activity increases in the so-called 'classical' language regions. The results suggest that besides perilesional and homologue language-associated regions, functional integrity of domain-unspecific memory structures may be a prerequisite for successful (intensive) language interventions.</p