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Cognitive skill learning postulates strategy generation and implementation when people learn to perform new tasks. Here we followed self-reported strategy use and objective performance in a working memory (WM) updating task to reveal strategy development that should take place when faced with this novel task. In two pre-registered online experiments with healthy adults, we examined short-term strategy acquisition in a ca 20-30-minute adaptive n-back WM task with 15 task blocks by collecting participants' strategy reports after each block. Experiment 1 showed that (a) about half of the participants reported using a strategy already during the very first task block, (b) changes in selected strategy were most common during the initial task blocks, and (c) more elaborated strategy descriptions predicted better task performance. Experiment 2 mostly replicated these findings, and it additionally showed that compared to open-ended questions, the use of repeated list-based strategy queries influenced subsequent strategy use and task performance, and also indicated higher rates of strategy implementation and strategy change during the task. Strategy use was also a significant predictor of n-back performance, albeit some of the variance it explained was shared with verbal productivity that was measured with a picture description task. The present results concur with the cognitive skill learning perspective and highlight the dynamics of carrying out a demanding cognitive task., (Copyright © 2020. Published by Elsevier B.V.)

The brain mechanisms of working memory (WM) training in humans remain unclear. Here we examined how WM updating training modulates a cascade of event-related potentials (ERPs) elicited at different processing stages. We hypothesized that WM updating training results to decreases in the early responses reflecting stimulus selection and response preparation, and increases the late slow responses reflecting maintenance of to-be-remembered materials. Healthy adults were randomized to a WM updating group that trained an adaptive dual n-back task (n = 20), and an active control group that played a computer game (n = 20). Both groups performed three 25-min training sessions per week for five weeks. Pretest-posttest comparisons showed that the training group significantly improved their performance as compared to the active controls, but this was limited to the trained task. In line with our hypothesis, P2-N2-P3 complex showed changes from pre- to posttest. In the training group this was observed as decreased load-effect while in the control group there was an opposite pattern at some latencies. Slow waves elicited during the maintenance were decreased in the easy task and increased in the difficult task. Taken together, our findings suggest that the early and late ERPs are differentially affected by training. When task demands are high, training may lead to an improved ability to actively maintain several stimuli in memory, and when they are low, training results in more efficient processing and automatization., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The mechanisms underlying working memory training remain unclear, but one possibility is that the typically limited transfer effects of this training reflect adoption of successful task-specific strategies. Our pre-registered randomized controlled trial (N = 116) studied the early effects of externally given vs. internally generated strategies in an updating task (n-back) over a 5-day period with a single 30-minute training session. Three groups were employed: n-back training with strategy instruction (n = 40), n-back training without strategy instruction (n = 37), and passive controls (n = 39). We found that both external and internal strategy use was associated with significantly higher posttest performance on the trained n-back task, and that training with n-back strategy instruction yielded positive transfer on untrained n-back tasks, resembling the transfer pattern typically seen after the ordinary uninstructed 4-6-week working memory training. In the uninstructed participants, the level of detail and type of internally generated n-back strategies at posttest was significantly related to their posttest n-back performance. Our results support the view that adoption of task-specific strategies plays an important role in working memory training outcomes, and that strategy-based effects are apparent right at the start of training.

Previous work demonstrates that working-memory (WM) updating training results in improved performance on a letter-memory criterion task, transfers to an untrained n-back task, and increases striatal dopamine (DA) activity during the criterion task. Here, we sought to replicate and extend these findings by also examining neurochemical correlates of transfer. Four positron emission tomography (PET) scans using the radioligand raclopride were performed. Two of these assessed DAD2 binding (letter memory; n-back) before 5 weeks of updating training, and the same two scans were performed post training. Key findings were (a) pronounced training-related behavioral gains in the letter-memory criterion task, (b) altered striatal DAD2 binding potential after training during letter-memory performance, suggesting training-induced increases in DA release, and (c) increased striatal DA activity also during the n-back transfer task after the intervention, but no concomitant behavioral transfer. The fact that the training-related DA alterations during the transfer task were not accompanied by behavioral transfer suggests that increased DA release may be a necessary, but not sufficient, condition for behavioral transfer to occur.

Morphology is an important part of language processing but little is known about how adult second language learners acquire morphological rules. Using a word-picture associative learning task, we have previously shown that a brief exposure to novel words with embedded morphological structure (suffix for natural gender) is enough for language learners to acquire the hidden morphological rule. Here we used this paradigm to study the brain signatures of early morphological learning in a novel language in adults. Behavioural measures indicated successful lexical (word stem) and morphological (gender suffix) learning. A day after the learning phase, event-related brain potentials registered during a recognition memory task revealed enhanced N400 and P600 components for stem and suffix violations, respectively. An additional effect observed with combined suffix and stem violations was an enhancement of an early N2 component, most probably related to conflict-detection processes. Successful morphological learning was also evident in the ERP responses to the subsequent rule-generalization task with new stems, where violation of the morphological rule was associated with an early (250-400ms) and late positivity (750-900ms). Overall, these findings tend to converge with lexical and morphosyntactic violation effects observed in L1 processing, suggesting that even after a short exposure, adult language learners can acquire both novel words and novel morphological rules., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In a randomized controlled trial, we investigated the pattern of near transfer effects of working memory (WM) training with an adaptive auditory-visuospatial dual n-back training task in healthy young adults. The results revealed significant task-specific transfer to an untrained single n-back task, and more general near transfer to a WM updating composite score plus a nearly significant effect on a composite score measuring interference control in WM. No transfer effects were seen on Active or Passive WM composites. The results are discussed in the light of cognitive versus strategy-related overlap between training and transfer tasks.

Recent research suggests that some people with aphasia preserve some ability to learn novel words and to retain them in the long-term. However, this novel word learning ability has been studied only in the context of single word-picture pairings. We examined the ability of people with chronic aphasia to learn novel words using a paradigm that presents new word forms together with a limited set of different possible visual referents and requires the identification of the correct word-object associations on the basis of online feedback. We also studied the relationship between word learning ability and aphasia severity, word processing abilities, and verbal short-term memory (STM). We further examined the influence of gross lesion location on new word learning. The word learning task was first validated with a group of forty-five young adults. Fourteen participants with chronic aphasia were administered the task and underwent tests of immediate and long-term recognition memory at 1 week. Their performance was compared to that of a group of fourteen matched controls using growth curve analysis. The learning curve and recognition performance of the aphasia group was significantly below the matched control group, although above-chance recognition performance and case-by-case analyses indicated that some participants with aphasia had learned the correct word-referent mappings. Verbal STM but not word processing abilities predicted word learning ability after controlling for aphasia severity. Importantly, participants with lesions in the left frontal cortex performed significantly worse than participants with lesions that spared the left frontal region both during word learning and on the recognition tests. Our findings indicate that some people with aphasia can preserve the ability to learn a small novel lexicon in an ambiguous word-referent context. This learning and recognition memory ability was associated with verbal STM capacity, aphasia severity and the integrity of the left inferior frontal region., Competing Interests: The authors declare no competing financial interests., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Ten participants learned a miniature language (Anigram), which they later employed to verbally describe a pictured event. Using magnetoencephalography, the cortical dynamics of sentence production in Anigram was compared with that in the native tongue from the preparation phase up to the production of the final word. At the preparation phase, a cartoon image with two animals prompted the participants to plan either the corresponding simple sentence (e.g., "the bear hits the lion") or a grammar-free list of the two nouns ("the bear, the lion"). For the newly learned language, this stage induced stronger left angular and adjacent inferior parietal activations than for the native language, likely reflecting a higher load on lexical retrieval and STM storage. The preparation phase was followed by a cloze task where the participants were prompted to produce the last word of the sentence or word sequence. Production of the sentence-final word required retrieval of rule-based inflectional morphology and was accompanied by increased activation of the left middle superior temporal cortex that did not differ between the two languages. Activation of the right temporal cortex during the cloze task suggested that this area plays a role in integrating word meanings into the sentence frame. The present results indicate that, after just a few days of exposure, the newly learned language harnesses the neural resources for multiword production much the same way as the native tongue and that the left and right temporal cortices seem to have functionally different roles in this processing.

In literates, reading is a fundamental channel for acquiring new vocabulary both in the mother tongue and in foreign languages. By using an artificial language learning task, we examined the acquisition of novel written words and their embedded regularities (an orthographic surface feature and a syllabic feature) in three groups of university students with different exposures (Group 1 saw 2 words once, Group 2 saw 20 words once, Group 3 saw 20 words three times). Recognition memory results for Groups 2 and 3 indicated that adults can learn novel written words even with just a single exposure, albeit repeated exposure improved target detection. A generalization task revealed that even the minimal exposure in Group 1 was enough for acquisition of the two embedded regularities. More exemplars and repeated exposure provided more robust effects for the syllable regularity. Finally, post-test interview showed that repeated exposure was needed to become aware of the regularities. The present results show that adults learn novel written words and their inherent regularities in a fast and effective fashion.

Updating of working memory has been associated with striato-frontal brain regions and phasic dopaminergic neurotransmission. We assessed raclopride binding to striatal dopamine (DA) D2 receptors during a letter-updating task and a control condition before and after 5 weeks of updating training. Results showed that updating affected DA activity before training and that training further increased striatal DA release during updating. These findings highlight the pivotal role of transient neural processes associated with D2 receptor activity in working memory.

The acquisition and maintenance of new language information, such as picking up new words, is a critical human ability that is needed throughout the life span. Most likely you learned the word "blog" quite recently as an adult, whereas the word "kipe," which in the 1970s denoted stealing, now seems unfamiliar. Brain mechanisms underlying the long-term maintenance of new words have remained unknown, albeit they could provide important clues to the considerable individual differences in the ability to remember words. After successful training of a set of novel object names we tracked, over a period of 10 months, the maintenance of this new vocabulary in 10 human participants by repeated behavioral tests and magnetoencephalography measurements of overt picture naming. When naming-related activation in the left frontal and temporal cortex was enhanced 1 week after training, compared with the level at the end of training, the individual retained a good command of the new vocabulary at 10 months; vice versa, individuals with reduced activation at 1 week posttraining were less successful in recalling the names at 10 months. This finding suggests an individual neural marker for memory, in the context of language. Learning is not over when the acquisition phase has been successfully completed: neural events during the access to recently established word representations appear to be important for the long-term outcome of learning.

Ten healthy adults encountered pictures of unfamiliar archaic tools and successfully learned either their name, verbal definition of their usage, or both. Neural representation of the newly acquired information was probed with magnetoencephalography in an overt picture-naming task before and after learning, and in two categorization tasks after learning. Within 400 ms, activation proceeded from occipital through parietal to left temporal cortex, inferior frontal cortex (naming) and right temporal cortex (categorization). Comparison of naming of newly learned versus familiar pictures indicated that acquisition and maintenance of word forms are supported by the same neural network. Explicit access to newly learned phonology when such information was known strongly enhanced left temporal activation. By contrast, access to newly learned semantics had no comparable, direct neural effects. Both the behavioral learning pattern and neurophysiological results point to fundamentally different implementation of and access to phonological versus semantic features in processing pictured objects.

Our objective was to study the neural correlates of naming of newly learned unfamiliar objects in subjects with mild cognitive impairment (MCI) and in age-matched controls, by using positron emission tomography (PET). Prior to the PET scanning, each subject underwent a 4-day long training period in which 40 names of rare unfamiliar objects were taught. The stimuli consisted of five categories: unfamiliar objects for which both the name and the definition (=semantic support) were given during training, unfamiliar objects with only the name given, unfamiliar objects with no information given, familiar objects and visual noise patterns. The unfamiliar objects mainly represented ancient domestic tools unknown to modern-day people. When naming newly learned objects trained without semantic support, the MCI group showed increased activation in the anterior cingulate when compared with the controls. Our results suggest that the naming of newly learned objects posed additional executive and attentional demands on the patients.

We explored functional brain changes with positron emission tomography (PET) in mild cognitive impairment (MCI) patients and elderly normal controls by employing an episodic memory task that included two successive encoding trials of semantically related word-pairs and final retrieval. Both groups demonstrated significant learning across the two trials. The control group showed predominantly left frontal activity during encoding, and right frontal plus left temporal activity during retrieval. However, the MCI patients recruited partly different brain regions. They failed to activate right frontal and left temporal areas during retrieval, and failed to show any different activation for encoding on the first and second trials, whereas the controls activated a region of posterior cingulate. There was indication of compensatory increases in rCBF of the occipital cortex during incremental learning and the left frontal lobe during retrieval in the patients. These results suggest different episodic memory processing in the MCI group, and a possible over-reliance on semantic processing. Subtle functional changes occur in the pre-Alzheimer brain before there are marked structural or behavioural abnormalities.

The present study tracked the naming-related brain activity by positron emission tomography (PET) when successfully learned unfamiliar objects were named. Ten Finnish-speaking subjects participated in the study. Prior to the PET scan, each subject underwent a 4-day long training period in which 40 names of rare unfamiliar objects were taught. The stimulus categories were as follows: unfamiliar but real objects for which both the name and the definition were given during training, only the name was given, no information was given. In addition, familiar objects and visual noise patterns were used. The unfamiliar items mainly represented ancient domestic tools unknown to modern-day people. As semantic support did not affect the PET results, all trained items were pooled together. The trained objects vs. familiar objects contrast revealed rCBF increases in the left inferior frontal cortex (Broca's area), the left anterior temporal area, and the cerebellum. Likewise, the trained objects vs. unfamiliar objects (for which no information was given) contrast revealed more extensive left frontal (roughly Broca's area) and cerebellar rCBF increases, while anterior temporal activation was bilateral. Familiar objects, contrasted with both visual noise patterns and a rest condition, elicited activation increases in expected areas, i.e., bilateral occipital regions and the fusiform gyrus. Our results indicate that the naming of newly learned objects recruits more extensive brain areas than the naming of familiar items, namely a network that includes left-dominant frontotemporal areas and cerebellum. Its activity is tentatively related to enhanced lexical-semantic and lexical-phonological retrieval, as well as associative memory processes.

We tracked the evolvement of naming-related cortical dynamics with magnetoencephalography when five normal adults successfully learned names and/or meanings of unfamiliar objects. In all subjects, the learning of new names was associated with pronounced cortical effects. The learning effect was of long latency and emerged as a change of activation in the same cortical network that was active during naming of familiar items. In four out of five subjects, the cortical learning effect occurred in the inferior parietal lobe. In three of these subjects, the cortical effect was left-sided. These results suggest that the inferior parietal lobe plays an important role in the acquisition of novel words, presumably as a part of working memory systems.

We describe a study where a specific treatment method for word-finding difficulty (so-called contextual priming technique, which combines massive repetition priming with semantic priming) was applied with three chronic left hemisphere-damaged aphasics. Both before and after treatment, which focused on naming of a series of pictures, naming-related brain activity was measured by magnetoencephalography (MEG). Due to its excellent temporal resolution and good spatial resolution, we were able to track treatment-induced changes in cortical activity. All three subjects showed improved naming of the trained items. In all subjects, a single source area, located in the left inferior parietal lobe, close to the lesioned area, displayed statistically significant training-induced changes. This effect was of long latency as it started 300-600 msec after picture presentation. The change in activation was specific to training, as it could not be accounted for by variation of cortical dynamics associated with increased proportion of correct answers. Our interpretation is that the training effect reflects more effective phonological encoding and storage of the trained items through the engagement of a left hemispheric word-learning system. This is in line with recent functional imaging studies, which have linked left inferior parietal lobe activity to the phonological storage component of the verbal working memory, as well as with theoretical arguments stating that the primary role of the phonological loop is to acquire new words. Finally, the MEG results showed no evidence of increased right hemisphere participation following training, supporting the view that restoration of language-related networks in the damaged left hemisphere is crucial for anomia recovery.

This study tested whether executive functioning (EF)/learning tasks from the CogState computerized test battery show a unitary latent structure. This information is important for the construction of composite measures on these tasks for applied research purposes. Based on earlier factor analytic research, we identified five CogState tasks that have been labeled as EF/learning tasks and examined their intercorrelations in a new sample of Finnish birth cohort mothers (N = 233). Using confirmatory factor analyses, we compared two single-factor EF/learning models. The first model included the recommended summative scores for each task. The second model exchanged summative scores for first test round results for the three tasks providing these data, as initial task performance is expected to load more heavily on EF. A single-factor solution provided a good fit for the present five EF/learning tasks. The second model, which was hypothesized to tap more onto EF, had slightly better fit indices, X[superscript 2](5) = 1.37, p = 0.93, standardized root mean square residual (SRMR) = 0.02, root mean square error of approximation (RMSEA) = 0.00, 90% CI = [0.00-0.03], comparative fit index (CFI) = 1.00, and more even factor loadings (0.30-0.56) than the first model, X[superscript 2](5) = 4.56, p = 0.47, SRMR = 0.03, RMSEA = 0.00, 90% CI = [0.00-0.09], CFI = 1.00, factor loadings (0.20-0.74), which was hypothesized to tap more onto learning. We conclude that the present CogState sum scores can be used for studying EF/learning in healthy adult samples, but call for further research to validate these sum scores against other EF tests.

The bilingual executive advantage (BEA) hypothesis has attracted considerable research interest, but the findings are inconclusive. We addressed this issue in the domain of working memory (WM), as more complex WM tasks have been underrepresented in the previous literature. First, we compared early and late bilingual vs. monolingual WM performance. Second, we examined whether certain aspects of bilingual experience, such as language switching frequency, are related to bilinguals’ WM scores. Our online sample included 485 participants. They filled in an extensive questionnaire including background factors such as bilingualism and second language (L2) use, and performed 10 isomorphic verbal and visuospatial WM tasks that yielded three WM composite scores (visuospatial WM, verbal WM, n-back). For verbal and visuospatial WM composites, the group comparisons did not support the BEA hypothesis. N-back analysis showed an advantage of late bilinguals over monolinguals and early bilinguals, while the latter two groups did not differ. This between-groups analysis was followed by a regression analysis relating features of bilingual experience to n-back performance, but the results were non-significant in both bilingual groups. In sum, group differences supporting the BEA hypothesis were limited only to the n-back composite, and this composite was not predicted by bilingualism-related features. Moreover, Bayesian analyses did not give consistent support for the BEA hypothesis. Possible reasons for the failure to find support for the BEA hypothesis are discussed. [ABSTRACT FROM AUTHOR]

We employed a highly demanding experimental associative learning test (the AFE-T) to explore memory functioning in Preclinical Alzheimer's Disease stage 1 (PreAD-1) and stage 2 (PreAD-2). The task consisted in the learning of unknown object/name pairs and our comprehensive setup allowed the analysis of learning curves, immediate recall, long-term forgetting rates at one week, three months, and six months, and relearning curves. Forty-nine cognitively healthy subjects were included and classified according to the presence or absence of abnormal CSF biomarkers (Control, n = 31; PreAD-1, n = 14; PreAD-2, n = 4). Control and PreAD-1 performances on the experimental test were compared by controlling for age and education. These analyses showed clear learning difficulties in PreAD-1 subjects (F = 6.98; p = 0.01). Between-group differences in long-term forgetting rates were less notable, reaching statistical significance only for the three-month cued forgetting rate (F = 4.83; p = 0.03). Similarly, relearning sessions showed only statistical trends between the groups (F = 3.22; p = 0.08). In the whole sample, significant correlations between CSF Aβ42/tau ratio and the AFE-T were found, both in the total learning score (r = 0.52; p < 0.001) and in the three-month cued forgetting rate (r = -0.38; p < 0.01). Descriptive subanalyses involving PreAD-2 suggested greater learning and recall difficulties in these subjects when compared with the PreAD-1 group. The present results suggest that explicit learning difficulties when binding information could be one of the earliest signs of the future emergence of episodic memory difficulties on the Alzheimer's disease continuum. Our findings indicate that the AFE-T is a sensitive test, capable of detecting subtle memory difficulties in PreAD-1. [ABSTRACT FROM AUTHOR]

Learning a new language is an incremental process that builds upon previously acquired information. To shed light on the mechanisms of this incremental process, we studied the on-line neurophysiological correlates of the so-called anchor word effect where newly learned words facilitate segmentation of novel words from continuous speech. Higher segmentation performance was observed for speech streams embedded with newly learned anchor words. The anchor words elicited an enhanced Stimulus-preceding negativity (SPN) component considered to be an index of expectation for incoming relevant information. Moreover, we confirmed a previously reported N400 amplitude increase for the to-be-segmented novel words, indicating a bottom-up learning process whereby new memory representations for the novel words emerge. We propose that the anchor word effect indexed by SPN reflects an expectation for an incoming novel word at the offset of the anchor word, thus facilitating the segmentation process. [ABSTRACT FROM AUTHOR]

Background: The study of novel word learning in aphasia can shed light on the functionality of patients' learning mechanisms and potentially help in treatment planning. Previous studies have indicated that persons with aphasia are able to learn some new vocabulary. However, these learning outcomes appear short-lived and evidence for the ability to use the newly learned words in the long term is lacking. Aims: Participants with aphasia and matched controls underwent short training where they were taught to name novel objects with novel names. We studied the participants' word learning and particularly their long-term maintenance. We also examined whether the language and verbal short-term memory impairments of the participants with aphasia related to their ability to acquire and maintain phonological and semantic information on novel words. Methods & Procedures: Two participants with nonfluent aphasia, LL and AR, and two matched controls took part in the experiment. They were taught to name 20 unfamiliar objects by repeating the names in the presence of the object picture. Half of the items carried a definition that was used to probe incidental semantic learning. There were four training sessions, a post-training test, and follow-up tests up to 6 months post-training. Learning measures included recognition of the trained objects, as well as spontaneous and cued recall in visual confrontation naming. Incidental semantic learning was measured by spontaneous recall of the definitions. Outcomes & Results: Combining spontaneous and phonologically cued responses, LL acquired 70% and AR 55% of the novel words. With phonological cueing, LL named 50% of the items correctly up to 6 months post-training (vs 95–100% for the controls) and AR 25% up to 8 weeks post-training. AR's lexical-semantic processing, pseudoword repetition and verbal short-term capacity were inferior to those of LL. In line with this, AR learned fewer words and showed more decline in recognition memory for the trained items, and weaker recall of the semantic definitions. Conclusions: Our results support previous findings that people with aphasia can learn to name novel items. More importantly, the results show for the first time that, with phonological cueing, an individual with aphasia can maintain some of this learning up to 6 months post-training. Moreover the results provide further evidence for the significance of the functional status of lexical-semantic processing on word learning success. [ABSTRACT FROM AUTHOR]

Background: Novel word learning of persons with aphasia is little studied, even though a better understanding of learning processes would inform development of effective treatment strategies. Recent evidence suggests some remaining verbal learning capacity in persons with aphasia. Long-term maintenance of newly learned active vocabulary has not been reported previously in persons with aphasia. Aims: To explore learning and long-term maintenance of novel words in persons with aphasia. Methods & Procedures: Two English-speaking males with chronic anomic aphasia and two age-matched controls were taught novel names of 20 unfamiliar objects. Half of the words were taught with semantic information (definition) and half without. Participants were instructed to learn the names. The experiment included four training sessions, one post-training test and four follow-up tests administered 1 week, 4 weeks, 8 weeks, and 6 months post-training. We tested explicit learning of the new names through visual confrontation naming. In addition, incidental learning of semantic information was probed over the follow-up period. Outcomes & Results: The two participants with aphasia learned 6-8 of the 20 novel names during the training. However, this new vocabulary dissipated during the 6-month follow-up. As expected, the controls showed better performance both in acquisition and in maintenance of the new vocabulary over the follow-up period. As regards the accuracy of semantic information, the aphasic participant with semantic impairment demonstrated worse incidental learning of semantic information than controls and the participant with intact lexical semantics. Conclusions: Some new vocabulary can be acquired even in chronic aphasia but the ability to spontaneously retrieve the newly learned words gradually dissipates over the weeks following learning. Our results also indicate an interaction between the level of lexical-semantic processing skills and incidental learning of new lexical-semantic knowledge in aphasia. [ABSTRACT FROM AUTHOR]

Here we review behavioral, neuroimaging, and neuropharmacological studies using a word learning task labeled as the Ancient Farming Equipment paradigm. This task has been used to explore the neural correlates of explicit learning and maintenance of new names for novel objects in the native tongue. The main conclusions drawn from these studies are as follows: (a) Retrieval of both the newly learned and familiar names is subserved by predominantly left hemispheric cortical regions; (b) within this network, retrieval of newly learned words can be accomplished in different ways depending on the exact form of training; (c) patient studies indicate that episodic memory mechanisms subserved by hippocampal structures are related to word acquisition rather than to long-term maintenance of newly learned words; (d) explicit learning and maintenance of novel words can be facilitated by neuropharmacological manipulation that boosts the dopaminergic system; and (b) neural events following completed training may predict long-term retention of newly learned words. [ABSTRACT FROM AUTHOR]

Evidence from infant studies indicates that language learning can be facilitated by multimodal cues. We extended this observation to adult language learning by studying the effects of simultaneous visual cues (nonassociated object images) on speech segmentation performance. Our results indicate that segmentation of new words from a continuous speech stream is facilitated by simultaneous visual input that it is presented at or near syllables that exhibit the low transitional probability indicative of word boundaries. This indicates that temporal audio-visual contiguity helps in directing attention to word boundaries at the earliest stages of language learning. Off-boundary or arrhythmic picture sequences did not affect segmentation performance, suggesting that the language learning system can effectively disregard noninformative visual information. Detection of temporal contiguity between multimodal stimuli may be useful in both infants and second-language learners not only for facilitating speech segmentation, but also for detecting word-object relationships in natural environments. [ABSTRACT FROM AUTHOR]

Humans continuously learn new information. Here, we examined the temporal brain dynamics of explicit verbal associative learning between unfamiliar items. In the first experiment, 25 adults learned object-pseudoword associations during a 5-day training program allowing us to track the N400 dynamics across learning blocks within and across days. Successful learning was accompanied by an initial frontal N400 that decreased in amplitude across blocks during the first day and shifted to parietal sites during the last training day. In Experiment 2, we replicated our findings with 38 new participants randomly assigned to a consistent learning or an inconsistent learning group. The N400 amplitude modulations that we found, both within and between learning sessions, are taken to reflect the emergence of novel lexical traces even when learning concerns items for which no semantic information is provided. The shift in N400 topography suggests that different N400 neural generators may contribute to specific word learning steps through a balance between domain-general and language-specific mechanisms. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Objective: Of current interest in aphasia research is the relevance of what we can learn from studying word learning ability in aphasia. In a preliminary study, we addressed 2 issues related to the novel word learning ability of individuals with aphasia. First, as word learning engages large-scale cognitive-linguistic systems (language skills, verbal short-term memory [STM], other memory and executive functions), we probed whether novel word learning practice in 3 people with aphasia could stimulate these language-related systems. Second, as lesion correlates affecting word learning in aphasia remain unclear, we examined whether the structural integrity of the left arcuate fasciculus (AF) in the same 3 individuals is related to outcomes of novel word learning practice. Method: To stimulate word learning systems, our 3 participants practiced for 4 weeks with an explicit novel word—novel referent word learning task, adopted from the Ancient Farming Equipment learning paradigm (Laine & Salmelin, 2010). The participants' progress on receptive and expressive novel word learning was followed up, and their language and verbal STM abilities as well as single-session novel word learning (Learning to Name Aliens by Gupta, Martin, Abbs, Schwartz, & Lipinski, 2006) were tested before and after the practice period. To address the second question, we analyzed the participants' structural magnetic resonance images with respect to the integrity of the left AF and its overlap with the lesion areas. Results: All participants showed some receptive word learning in the trained task, as well as improvements in verbal STM span at posttesting. Two of the 3 participants also showed improved performance on some of the language outcome measures. One participant with a partially spared left AF, especially temporoparietal connections, exhibited better word learning performance than the other 2 who had larger damage and disconnection of the AF. Conclusions: Although the present results are preliminary, they open the possibility that novel word learning practice in aphasia may stimulate remaining word learning mechanisms in aphasia and thereby influence language and verbal STM abilities. These results also suggest that preservation of novel word learning ability in aphasia in part depends on the integrity of the left arcuate track. [ABSTRACT FROM AUTHOR]

This study investigated effects of multisession transcranial direct-current stimulation on learning and maintenance of novel memory content and scrutinised effects of baseline cognitive status and the role of multi-session tDCS on overnight memory consolidation. In a prospective, randomized, double-blind, parallel-group, sham-tDCS controlled design, 101 healthy young and older adults completed a five-day verbal associative learning paradigm while receiving multisession tDCS to the task-relevant left prefrontal cortex. In older adults, active multisession tDCS enhanced recall performance after each daily training session. Effects were maintained the next morning and during follow-up assessments (one week; three months). In young adults, multisession tDCS significantly increased long-term recall. Unlike previous findings in the motor domain, beneficial effects of multisession tDCS on cognitive learning and memory were notexclusively due to enhanced memory consolidation. Positive stimulation effects were primarily found in participants with lower baseline learning ability, suggesting that multisession tDCS may counteract memory impairment in health and disease. [ABSTRACT FROM AUTHOR]