Distinct patterns of functional and structural neuroplasticity associated with learning Morse code

Generalization of auditory expertise in audio engineers and instrumental musicians

From auditory perception to general cognition, the ability to play a musical instrument has been associated with skills both related and unrelated to music. However, it is unclear if these effects are bound to the specific characteristics of musical instrument training, as little attention has been paid to other populations such as audio engineers and designers whose auditory expertise may match or surpass that of musicians in specific auditory tasks or more naturalistic acoustic scenarios. We explored this possibility by comparing students of audio engineering (n = 20) to matched conservatory-trained instrumentalists (n = 24) and to naive controls (n = 20) on measures of auditory discrimination, auditory scene analysis, and speech in noise perception. We found that audio engineers and performing musicians had generally lower psychophysical thresholds than controls, with pitch perception showing the largest effect size. Compared to controls, audio engineers could better memorise and recall auditory scenes composed of non-musical sounds, whereas instrumental musicians performed best in a sustained selective attention task with two competing streams of tones. Finally, in a diotic speech-in-babble task, musicians showed lower signal-to-noise-ratio thresholds than both controls and engineers; however, a follow-up online study did not replicate this musician advantage. We also observed differences in personality that might account for group-based self-selection biases. Overall, we showed that investigating a wider range of forms of auditory expertise can help us corroborate (or challenge) the specificity of the advantages previously associated with musical instrument training.

Cortical Thickness Related to Compensatory Viewing Strategies in Patients With Macular Degeneration

Retinal diseases like age-related macular degeneration (AMD) or hereditary juvenile macular dystrophies (JMD) lead to a loss of central vision. Many patients compensate for this loss with a pseudo fovea in the intact peripheral retina, the so-called "preferred retinal locus" (PRL). How extensive eccentric viewing associated with central vision loss (CVL) affects brain structures responsible for visual perception and visually guided eye movements remains unknown. CVL results in a reduction of cortical gray matter in the "lesion projection zone" (LPZ) in early visual cortex, but the thickness of primary visual cortex appears to be largely preserved for eccentric-field representations. Here we explore how eccentric viewing strategies are related to cortical thickness (CT) measures in early visual cortex and in brain areas involved in the control of eye movements (frontal eye fields, FEF, supplementary eye fields, SEF, and premotor eye fields, PEF). We determined the projection zones (regions of interest, ROIs) of the PRL and of an equally peripheral area in the opposite hemifield (OppPRL) in early visual cortex (V1 and V2) in 32 patients with MD and 32 age-matched controls (19-84 years) by functional magnetic resonance imaging. Subsequently, we calculated the CT in these ROIs and compared it between PRL and OppPRL as well as between groups. Additionally, we examined the CT of FEF, SEF, and PEF and correlated it with behavioral measures like reading speed and eccentric fixation stability at the PRL. We found a significant difference between PRL and OppPRL projection zones in V1 with increased CT at the PRL, that was more pronounced in the patients, but also visible in the controls. Although the mean CT of the eye fields did not differ significantly between patients and controls, we found a trend to a positive correlation between CT in the right FEF and SEF and fixation stability in the whole patient group and between CT in the right PEF and reading speed in the JMD subgroup. The results indicate a possible association between the compensatory strategies used by patients with CVL and structural brain properties in early visual cortex and cortical eye fields.

Cognitive Activity and Onset Age of Incident Alzheimer Disease Dementia

OBJECTIVE

To test the hypothesis that higher level of cognitive activity predicts older age at dementia onset in Alzheimer disease (AD) dementia.

METHODS

As part of a longitudinal cohort study, 1,903 older persons without dementia at enrollment reported their frequency of participation in cognitively stimulating activities. They had annual clinical evaluations to diagnose dementia and AD, and the deceased underwent neuropathologic examination. In analyses, we assessed the relation of baseline cognitive activity to age at diagnosis of incident AD dementia and to postmortem markers of AD and other dementias.

RESULTS

During a mean of 6.8 years of follow-up, 457 individuals were diagnosed with incident AD at a mean age of 88.6 (SD 6.4, range 64.1-106.5) years. In an extended accelerated failure time model, higher level of baseline cognitive activity (mean 3.2, SD 0.7) was associated with older age at AD dementia onset (estimate 0.026; 95% confidence interval 0.013-0.039). Low cognitive activity (score 2.1, 10th percentile) was associated with a mean onset age of 88.6 years compared to a mean onset age of 93.6 years associated with high cognitive activity (score 4.0, 90th percentile). Results were comparable in subsequent analyses that adjusted for potentially confounding factors. In 695 participants who died and underwent a neuropathologic examination, cognitive activity was unrelated to postmortem markers of AD and other dementias.

CONCLUSION

A cognitively active lifestyle in old age may delay the onset of dementia in AD by as much as 5 years.

Age of Acquisition of Mandarin Modulates Cortical Thickness in High-Proficient Cantonese-Mandarin Bidialectals

Previous studies showed that the onset age of second language acquisition (AoA-L2) can modulate brain structure of bilinguals. However, the underlying mechanism of anatomical plasticity induced by AoA-L2 is still a question in debate. In order to explore the issue, we recruited two groups of native Cantonese-Mandarin speakers, the early group began to speak in Mandarin at about 3.5 and the late group at about 6.5 years old. In addition, the early group had earlier experience in reading Chinese characters than the late group did. Through estimating the cortical thickness (CT), we found that (1) compared with the late group, the early group had thicker CT in the lateral occipital region, left middle temporal gyrus, and left parahippocampal region, which are all involved in visuospatial processing, probably reflecting the effect induced by the earlier or later experiences in processing the characters of Chinese for the two groups; and (2) compared with the late group, the early group had thicker CT in left superior parietal region, which is believed to be involved in language switching, maybe for the early group had the earlier experience in switching back and forth between Cantonese and Mandarin and therefore recruited the executive control network earlier. Our findings revealed the effects of the AoA-L2 in oral language acquisition as well as in written language acquisition as the main determinants of bilingual language structural representation in human brain.

Using Fractal Dimension Analysis with the Desikan-Killiany Atlas to Assess the Effects of Normal Aging on Subregional Cortex Alterations in Adulthood

Normal aging is associated with functional and structural alterations in the human brain. The effects of normal aging and gender on morphological changes in specific regions of the brain are unknown. The fractal dimension (FD) can be a quantitative measure of cerebral folding. In this study, we used 3D-FD analysis with the Desikan–Killiany (DK) atlas to assess subregional morphological changes in adulthood. A total of 258 participants (112 women and 146 men) aged 30–85 years participated in this study. Participants in the middle-age group exhibited a decreased FD in the lateral frontal lobes, which then spread to the temporal and parietal lobes. Men exhibited an earlier and more significant decrease in FD values, mainly in the right frontal and left parietal lobes. Men exhibited more of a decrease in FD values in the subregions on the left than those in the right, whereas women exhibited more of a decrease in the lateral subregions. Older men were at a higher risk of developing mild cognitive impairment (MCI) and exhibited age-related memory decline earlier than women. Our FD analysis using the DK atlas-based prediagnosis may provide a suitable tool for assessing normal aging and neurodegeneration between groups or in individual patients.

Post-learning micro- and macro-structural neuroplasticity changes with time and sleep

Neuroplasticity refers to the fact that our brain can partially modify both structure and function to adequately respond to novel environmental stimulations. Neuroplasticity mechanisms are not only operating during the acquisition of novel information (i.e., online) but also during the offline periods that take place after the end of the actual learning episode. Structural brain changes as a consequence of learning have been consistently demonstrated on the long term using non-invasive neuroimaging methods, but short-term changes remained more elusive. Fortunately, the swift development of advanced MR methods over the last decade now allows tracking fine-grained cerebral changes on short timescales beyond gross volumetric modifications stretching over several days or weeks. Besides a mere effect of time, post-learning sleep mechanisms have been shown to play an important role in memory consolidation and promote long-lasting changes in neural networks. Sleep was shown to contribute to structural modifications over weeks of prolonged training, but studies evidencing more rapid post-training sleep structural effects linked to memory consolidation are still scarce in human. On the other hand, animal studies convincingly show how sleep might modulate synaptic microstructure. We aim here at reviewing the literature establishing a link between different types of training/learning and the resulting structural changes, with an emphasis on the role of post-training sleep and time in tuning these modifications. Open questions are raised such as the role of post-learning sleep in macrostructural changes, the links between different MR structural measurement-related modifications and the underlying microstructural brain processes, and bidirectional influences between structural and functional brain changes.

Brain plasticity dynamics during tactile Braille learning in sighted subjects: Multi-contrast MRI approach

A growing body of empirical evidence supports the notion of diverse neurobiological processes underlying learning-induced plasticity changes in the human brain. There are still open questions about how brain plasticity depends on cognitive task complexity, how it supports interactions between brain systems and with what temporal and spatial trajectory. We investigated brain and behavioural changes in sighted adults during 8-months training of tactile Braille reading whilst monitoring brain structure and function at 5 different time points. We adopted a novel multivariate approach that includes behavioural data and specific MRI protocols sensitive to tissue properties to assess local functional and structural and myelin changes over time. Our results show that while the reading network, located in the ventral occipitotemporal cortex, rapidly adapts to tactile input, sensory areas show changes in grey matter volume and intra-cortical myelin at different times. This approach has allowed us to examine and describe neuroplastic mechanisms underlying complex cognitive systems and their (sensory) inputs and (motor) outputs differentially, at a mesoscopic level.

Transition From Sublexical to Lexico-Semantic Stimulus Processing

Resembling letter-by-letter translation, Morse code can be used to investigate various linguistic components by slowing down the cognitive process of language decoding. Using fMRI and Morse code, we investigated patterns of brain activation associated with decoding three-letter words or non-words and making a lexical decision. Our data suggest that early sublexical processing is associated with activation in brain regions that are involved in sound-patterns to phoneme conversion (inferior parietal lobule), phonological output buffer (inferior frontal cortex: pars opercularis) as well as phonological and semantic top-down predictions (inferior frontal cortex: pars triangularis). In addition, later lexico-semantic processing of meaningful stimuli is associated with activation of the phonological lexicon (angular gyrus) and the semantic system (default mode network). Overall, our data indicate that sublexical and lexico-semantic analyses comprise two cognitive processes that rely on neighboring networks in the left frontal cortex and parietal lobule.

Multimodal imaging of brain reorganization in hearing late learners of sign language

The neural plasticity underlying language learning is a process rather than a single event. However, the dynamics of training-induced brain reorganization have rarely been examined, especially using a multimodal magnetic resonance imaging approach, which allows us to study the relationship between functional and structural changes. We focus on sign language acquisition in hearing adults who underwent an 8-month long course and five neuroimaging sessions. We assessed what neural changes occurred as participants learned a new language in a different modality-as reflected by task-based activity, connectivity changes, and co-occurring structural alterations. Major changes in the activity pattern appeared after just 3 months of learning, as indicated by increases in activation within the modality-independent perisylvian language network, together with increased activation in modality-dependent parieto-occipital, visuospatial and motion-sensitive regions. Despite further learning, no alterations in activation were detected during the following months. However, enhanced coupling between left-lateralized occipital and inferior frontal regions was observed as the proficiency increased. Furthermore, an increase in gray matter volume was detected in the left inferior frontal gyrus which peaked at the end of learning. Overall, these results showed complexity and temporal distinctiveness of various aspects of brain reorganization associated with learning of new language in different sensory modality.

Programmable and Shape-Memorizing Information Carriers

Shape memory polymers (SMPs) are expected to play more and more important roles in space-deployable structures, smart actuators, and other high-tech areas. Nevertheless, because of the difficulties in fabrication and the programmability of temporary shape recovery, SMPs have not yet been widely applied in real fields. It is ideal to incorporate the different independent functional building blocks into a material. Herein, we designed a simple method to incorporate four functional building blocks: a neat epoxy-based shape memory (neat SMEP) resin, an SMEP composited with Fe₃O₄ (SMEP-Fe₃O₄), an SMEP composited with multiwalled carbon nanotubes, and an SMEP composited with p-aminodiphenylimide into a multicomposite, in which the four region surfaces could be programmed with different language code patterns according to a preset command by imprint lithography. Then, we aimed to reprogram the initially raised code patterns into temporary flat patterns using programming mold that, when triggered by a preset stimulus process such as an alternating magnetic field, radiofrequency field, 365 nm UV, and direct heating, could transform these language codes into the information passed by the customer. The concept introduced here will be applied to other available SMPs and provide a practical method to realize the information delivery.

Short-term apparent brain tissue changes are contributed by cerebral blood flow alterations

Structural MRI (sMRI)-identified tissue "growth" after neuropsychological training has been reported in many studies but the origins of those apparent tissue changes (ATC) still remain elusive. One possible contributor to ATC is brain perfusion since T1-weighted MRI, the tool used to identify ATC, is sensitive to perfusion-change induced tissue T1 alterations. To test the hypothetical perfusion contribution to ATC, sMRI data were acquired before and after short-term global and regional perfusion manipulations via intaking a 200 mg caffeine pill and performing a sensorimotor task. Caffeine intake caused a global CBF reduction and apparent tissue density reduction in temporal cortex, anterior cingulate cortex, and the limbic area; sensorimotor task induced CBF increase and apparent tissue increase in spatially overlapped brain regions. After compensating CBF alterations through a voxel-wise regression, the ATC patterns demonstrated in both experiments were substantially suppressed. These data clearly proved existence of the perfusion contribution to short-term ATC, and suggested a need for correcting perfusion changes in longitudinal T1-weighted structural MRI analysis if a short-term design is used.

Bilingualism Influences Structural Indices of Interhemispheric Organization

Bilingualism represents an interesting model of possible experience-dependent alterations in brain structure. The current study examines whether interhemispheric adaptations in brain structure are associated with bilingualism. Corpus callosum volume and cortical thickness asymmetry across 13 regions of interest (selected to include critical language and bilingual cognitive control areas) were measured in a sample of Spanish-English bilinguals and age- and gender-matched monolingual individuals (N = 39 per group). Cortical thickness asymmetry of the anterior cingulate region differed across groups, with thicker right than left cortex for bilinguals and the reverse for monolinguals. In addition, two adjacent regions of the corpus callosum (mid-anterior and central) had greater volume in bilinguals. The findings suggest that structural indices of interhemispheric organization in a critical cognitive control region are sensitive to variations in language experience.

Strategy-based reasoning training modulates cortical thickness and resting-state functional connectivity in adults with chronic traumatic brain injury

INTRODUCTION

Prior studies have demonstrated training-induced changes in the healthy adult brain. Yet, it remains unclear how the injured brain responds to cognitive training months-to-years after injury.

METHODS

Sixty individuals with chronic traumatic brain injury (TBI) were randomized into either strategy-based (N = 31) or knowledge-based (N = 29) training for 8 weeks. We measured cortical thickness and resting-state functional connectivity (rsFC) before training, immediately posttraining, and 3 months posttraining.

RESULTS

Relative to the knowledge-based training group, the cortical thickness of the strategy-based training group showed diverse temporal patterns of changes over multiple brain regions (pvertex < .05, pcluster < .05): (1) increases followed by decreases, (2) monotonic increases, and (3) monotonic decreases. However, network-based statistics (NBS) analysis of rsFC among these regions revealed that the strategy-based training group induced only monotonic increases in connectivity, relative to the knowledge-based training group (|Z| > 1.96, pNBS < 0.05). Complementing the rsFC results, the strategy-based training group yielded monotonic improvement in scores for the trail-making test (p < .05). Analyses of brain-behavior relationships revealed that improvement in trail-making scores were associated with training-induced changes in cortical thickness (pvertex < .05, pcluster < .05) and rsFC (pvertex < .05, pcluster < .005) within the strategy-based training group.

CONCLUSIONS

These findings suggest that training-induced brain plasticity continues through chronic phases of TBI and that brain connectivity and cortical thickness may serve as markers of plasticity.

Functional and Structural Neuroplasticity Induced by Short-Term Tactile Training Based on Braille Reading

Neuroplastic changes induced by sensory learning have been recognized within the cortices of specific modalities as well as within higher ordered multimodal areas. The interplay between these areas is not fully understood, particularly in the case of somatosensory learning. Here we examined functional and structural changes induced by short-term tactile training based of Braille reading, a task that requires both significant tactile expertise and mapping of tactile input onto multimodal representations. Subjects with normal vision were trained for 3 weeks to read Braille exclusively by touch and scanned before and after training, while performing a same-different discrimination task on Braille characters and meaningless characters. Functional and diffusion-weighted magnetic resonance imaging sequences were used to assess resulting changes. The strongest training-induced effect was found in the primary somatosensory cortex (SI), where we observed bilateral augmentation in activity accompanied by an increase in fractional anisotropy (FA) within the contralateral SI. Increases of white matter fractional anisotropy were also observed in the secondary somatosensory area (SII) and the thalamus. Outside of somatosensory system, changes in both structure and function were found in i.e., the fusiform gyrus, the medial frontal gyri and the inferior parietal lobule. Our results provide evidence for functional remodeling of the somatosensory pathway and higher ordered multimodal brain areas occurring as a result of short-lasting tactile learning, and add to them a novel picture of extensive white matter plasticity.

From perceptual to lexico-semantic analysis--cortical plasticity enabling new levels of processing

Certain kinds of stimuli can be processed on multiple levels. While the neural correlates of different levels of processing (LOPs) have been investigated to some extent, most of the studies involve skills and/or knowledge already present when performing the task. In this study we specifically sought to identify neural correlates of an evolving skill that allows the transition from perceptual to a lexico-semantic stimulus analysis. Eighteen participants were trained to decode 12 letters of Morse code that were presented acoustically inside and outside of the scanner environment. Morse code was presented in trains of three letters while brain activity was assessed with fMRI. Participants either attended to the stimulus length (perceptual analysis), or evaluated its meaning distinguishing words from nonwords (lexico-semantic analysis). Perceptual and lexico-semantic analyses shared a mutual network comprising the left premotor cortex, the supplementary motor area (SMA) and the inferior parietal lobule (IPL). Perceptual analysis was associated with a strong brain activation in the SMA and the superior temporal gyrus bilaterally (STG), which remained unaltered from pre and post training. In the lexico-semantic analysis post learning, study participants showed additional activation in the left inferior frontal cortex (IFC) and in the left occipitotemporal cortex (OTC), regions known to be critically involved in lexical processing. Our data provide evidence for cortical plasticity evolving with a learning process enabling the transition from perceptual to lexico-semantic stimulus analysis. Importantly, the activation pattern remains task-related LOP and is thus the result of a decision process as to which LOP to engage in.

Structural and Functional Alterations in Right Dorsomedial Prefrontal and Left Insular Cortex Co-Localize in Adolescents with Aggressive Behaviour: An ALE Meta-Analysis

Recent neuroimaging work has suggested that aggressive behaviour (AB) is associated with structural and functional brain abnormalities in processes subserving emotion processing and regulation. However, most neuroimaging studies on AB to date only contain relatively small sample sizes. To objectively investigate the consistency of previous structural and functional research in adolescent AB, we performed a systematic literature review and two coordinate-based activation likelihood estimation meta-analyses on eight VBM and nine functional neuroimaging studies in a total of 783 participants (408 [224AB/184 controls] and 375 [215 AB/160 controls] for structural and functional analysis respectively). We found 19 structural and eight functional foci of significant alterations in adolescents with AB, mainly located within the emotion processing and regulation network (including orbitofrontal, dorsomedial prefrontal and limbic cortex). A subsequent conjunction analysis revealed that functional and structural alterations co-localize in right dorsomedial prefrontal cortex and left insula. Our results are in line with meta-analytic work as well as structural, functional and connectivity findings to date, all of which make a strong point for the involvement of a network of brain areas responsible for emotion processing and regulation, which is disrupted in AB. Increased knowledge about the behavioural and neuronal underpinnings of AB is crucial for the development of novel and implementation of existing treatment strategies. Longitudinal research studies will have to show whether the observed alterations are a result or primary cause of the phenotypic characteristics in AB.

Brain Imaging in Gambling Disorder

Gambling disorder recently was reclassified under the category “substance-related and addictive disorders.” With regard to the diagnostic criteria, it overlaps a great deal with substance use disorder, i.e., loss of control, craving/withdrawal, and neglect of other areas of life. However, the gambling disorder symptom “chasing one’s losses” is the only criterion absent from substance use disorder. Therefore, special forms of reward (i.e., gain/loss) processing, such as the processing of loss avoidance and loss aversion, have just recently attracted attention among gambling disorder researchers. Because gambling disorder might be considered an addiction in its “pure” form, i.e., without the influence of a drug of abuse, investigating brain volume changes in people with this behavioral addiction is an important task for neuroimaging researchers in exploring the neural signatures of addiction. Because the brain is a complex network, investigation of alterations in functional connectivity has gained interest among gambling disorder researchers in order to get a more complete picture of functional brain changes in people with gambling disorder. However, only a few studies on brain structure and functional connectivity in gambling disorder have been performed so far. This review focuses on brain imaging studies of reward and loss processing, with an emphasis on loss avoidance and aversion as well as brain volume and functional connectivity in gambling disorder.

Brain enhancement through cognitive training: a new insight from brain connectome

Owing to the recent advances in neurotechnology and the progress in understanding of brain cognitive functions, improvements of cognitive performance or acceleration of learning process with brain enhancement systems is not out of our reach anymore, on the contrary, it is a tangible target of contemporary research. Although a variety of approaches have been proposed, we will mainly focus on cognitive training interventions, in which learners repeatedly perform cognitive tasks to improve their cognitive abilities. In this review article, we propose that the learning process during the cognitive training can be facilitated by an assistive system monitoring cognitive workloads using electroencephalography (EEG) biomarkers, and the brain connectome approach can provide additional valuable biomarkers for facilitating leaners' learning processes. For the purpose, we will introduce studies on the cognitive training interventions, EEG biomarkers for cognitive workload, and human brain connectome. As cognitive overload and mental fatigue would reduce or even eliminate gains of cognitive training interventions, a real-time monitoring of cognitive workload can facilitate the learning process by flexibly adjusting difficulty levels of the training task. Moreover, cognitive training interventions should have effects on brain sub-networks, not on a single brain region, and graph theoretical network metrics quantifying topological architecture of the brain network can differentiate with respect to individual cognitive states as well as to different individuals' cognitive abilities, suggesting that the connectome is a valuable approach for tracking the learning progress. Although only a few studies have exploited the connectome approach for studying alterations of the brain network induced by cognitive training interventions so far, we believe that it would be a useful technique for capturing improvements of cognitive functions.

Differential patterns of functional and structural plasticity within and between inferior frontal gyri support training-induced improvements in inhibitory control proficiency

Ample evidence indicates that inhibitory control (IC), a key executive component referring to the ability to suppress cognitive or motor processes, relies on a right-lateralized fronto-basal brain network. However, whether and how IC can be improved with training and the underlying neuroplastic mechanisms remains largely unresolved. We used functional and structural magnetic resonance imaging to measure the effects of 2 weeks of training with a Go/NoGo task specifically designed to improve frontal top-down IC mechanisms. The training-induced behavioral improvements were accompanied by a decrease in neural activity to inhibition trials within the right pars opercularis and triangularis, and in the left pars orbitalis of the inferior frontal gyri. Analyses of changes in brain anatomy induced by the IC training revealed increases in grey matter volume in the right pars orbitalis and modulations of white matter microstructure in the right pars triangularis. The task-specificity of the effects of training was confirmed by an absence of change in neural activity to a control working memory task. Our combined anatomical and functional findings indicate that differential patterns of functional and structural plasticity between and within inferior frontal gyri enhanced the speed of top-down inhibition processes and in turn IC proficiency. The results suggest that training-based interventions might help overcoming the anatomic and functional deficits of inferior frontal gyri manifesting in inhibition-related clinical conditions. More generally, we demonstrate how multimodal neuroimaging investigations of training-induced neuroplasticity enable revealing novel anatomo-functional dissociations within frontal executive brain networks.

Early life instruction in foreign language and music and incidence of mild cognitive impairment

OBJECTIVE

To test the hypothesis that foreign language and music instruction in early life are associated with lower incidence of mild cognitive impairment (MCI) and slower rate of cognitive decline in old age.

METHOD

At enrollment in a longitudinal cohort study, 964 older persons without cognitive impairment estimated years of foreign language and music instruction by age 18. Annually thereafter they completed clinical evaluations that included cognitive testing and clinical classification of MCI.

RESULTS

There were 264 persons with no foreign language instruction, 576 with 1-4 years, and 124 with > 4 years; 346 persons with no music instruction, 360 with 1-4 years, and 258 with > 4 years. During a mean of 5.8 years of observation, 396 participants (41.1%) developed MCI. In a proportional hazards model adjusted for age, sex, and education, higher levels (> 4 years) of foreign language (hazard ratio [HR] = 0.687, 95% confidence interval [CI] [0.482, 0.961]) and music (HR = 0.708, 95% CI [0.539, 0.930]) instruction by the age of 18 were each associated with reduced risk of MCI. The association persisted after adjustment for other early life indicators of an enriched cognitive environment, and it was stronger for nonamnestic than amnestic MCI. Both foreign language and music instruction were associated with higher initial level of cognitive function, but neither instruction measure was associated with cognitive decline.

CONCLUSIONS

Higher levels of foreign language and music instruction during childhood and adolescence are associated in old age with lower risk of developing MCI but not with rate of cognitive decline.

Mind over matter--what do we know about neuroplasticity in adults?

BACKGROUND

An increasing number of studies have examined the effects of training of cognitive and other tasks on brain structure, using magnetic resonance imaging.

METHODS

Studies combining cognitive and other tasks training with longitudinal imaging designs were reviewed, with a view to identify paradigms potentially applicable to treatment of cognitive impairment.

RESULTS

We identified 36 studies, employing training as variable as juggling, working memory, meditation, learning abstract information, and aerobic exercise. There were training-related structural changes, increases in gray matter volume, decreases, increases and decreases in different regions, or no change at all. There was increased integrity in white matter following training, but other patterns of results were also reported.

CONCLUSIONS

Questions still to be answered are: Are changes due to use-dependent effects or are they specific to learning? What are the underlying neural correlates of learning, the temporal dynamics of changes, the relations between structure and function, and the upper limits of improvement? How can gains be maintained? The question whether neuroplasticity will contribute to the treatment of dementia will need to be posed again at that stage.

Positive association of video game playing with left frontal cortical thickness in adolescents

Playing video games is a common recreational activity of adolescents. Recent research associated frequent video game playing with improvements in cognitive functions. Improvements in cognition have been related to grey matter changes in prefrontal cortex. However, a fine-grained analysis of human brain structure in relation to video gaming is lacking. In magnetic resonance imaging scans of 152 14-year old adolescents, FreeSurfer was used to estimate cortical thickness. Cortical thickness across the whole cortical surface was correlated with self-reported duration of video gaming (hours per week). A robust positive association between cortical thickness and video gaming duration was observed in left dorsolateral prefrontal cortex (DLPFC) and left frontal eye fields (FEFs). No regions showed cortical thinning in association with video gaming frequency. DLPFC is the core correlate of executive control and strategic planning which in turn are essential cognitive domains for successful video gaming. The FEFs are a key region involved in visuo-motor integration important for programming and execution of eye movements and allocation of visuo-spatial attention, processes engaged extensively in video games. The results may represent the biological basis of previously reported cognitive improvements due to video game play. Whether or not these results represent a-priori characteristics or consequences of video gaming should be studied in future longitudinal investigations.

A stereoscopic system for viewing the temporal evolution of brain activity clusters in response to linguistic stimuli

In this paper, we present a novel application, 3D+Time Brain View, for the stereoscopic visualization of functional Magnetic Resonance Imaging (fMRI) data gathered from participants exposed to unfamiliar spoken languages. An analysis technique based on Independent Component Analysis (ICA) is used to identify statistically significant clusters of brain activity and their changes over time during different testing sessions. That is, our system illustrates the temporal evolution of participants' brain activity as they are introduced to a foreign language through displaying these clusters as they change over time. The raw fMRI data is presented as a stereoscopic pair in an immersive environment utilizing passive stereo rendering. The clusters are presented using a ray casting technique for volume rendering. Our system incorporates the temporal information and the results of the ICA into the stereoscopic 3D rendering, making it easier for domain experts to explore and analyze the data.

Losses and gains: chronic pain and altered brain morphology

As in many fields of neuroscience, alterations in brain morphology, and specifically gray matter volume and cortical thickness, have been repeatedly linked to chronic pain disorders. Numerous studies have shown changes in cortical and subcortical brain regions suggesting a dynamic process that may be a result of chronic pain or contributing to a more generalized phenomenon in chronic pain including comorbid anxiety and depression. In this review, we provide a perspective of pain as an innate state of pain based on alterations in structure and by inference, brain function. A better neurobiological understanding of gray matter changes will contribute to our understanding of how structural changes contribute to chronic pain (disease driver) and how these changes may be reversed (disease modification or treatment).

Efficiency, capacity, compensation, maintenance, plasticity: emerging concepts in cognitive reserve

Cognitive reserve (CR) is a concept meant to account for the frequent discrepancy between an individual's measured level of brain pathology and her expected cognitive performance. It is particularly important within the context of aging and dementia, but has wider applicability to all forms of brain damage. As such, it has intimate links to related compensatory and neuroprotective concepts, as well as to the related notion of brain reserve. In this article, we introduce the concept of cognitive reserve and explicate its potential cognitive and neural implementation. We conclude that cognitive reserve is compatible and complementary with many related concepts, but that each much draw sharper conceptual boundaries in order to truly explain preserved cognitive function in the face of aging or brain damage.

Life-span cognitive activity, neuropathologic burden, and cognitive aging

OBJECTIVE

To test the hypothesis that cognitive activity across the life span is related to late-life cognitive decline not linked to common neuropathologic disorders.

METHODS

On enrollment, older participants in a longitudinal clinical-pathologic cohort study rated late-life (i.e., current) and early-life participation in cognitively stimulating activities. After a mean of 5.8 years of annual cognitive function testing, 294 individuals had died and undergone neuropathologic examination. Chronic gross infarcts, chronic microscopic infarcts, and neocortical Lewy bodies were identified, and measures of β-amyloid burden and tau-positive tangle density in multiple brain regions were derived.

RESULTS

In a mixed-effects model adjusted for age at death, sex, education, gross and microscopic infarction, neocortical Lewy bodies, amyloid burden, and tangle density, more frequent late-life cognitive activity (estimate = 0.028, standard error [SE] = 0.008, p < 0.001) and early-life cognitive activity (estimate = 0.034, SE = 0.013, p = 0.008) were each associated with slower cognitive decline. The 2 measures together accounted for 14% of the residual variability in cognitive decline not related to neuropathologic burden. The early-life-activity association was attributable to cognitive activity in childhood (estimate = 0.027, SE = 0.012, p = 0.026) and middle age (estimate = 0.029, SE = 0.013, p = 0.025) but not young adulthood (estimate = -0.020, SE = 0.014, p = 0.163).

CONCLUSIONS

More frequent cognitive activity across the life span has an association with slower late-life cognitive decline that is independent of common neuropathologic conditions, consistent with the cognitive reserve hypothesis.

Differential brain shrinkage over 6 months shows limited association with cognitive practice

The brain shrinks with age, but the timing of this process and the extent of its malleability are unclear. We measured changes in regional brain volumes in younger (age 20-31) and older (age 65-80) adults twice over a 6 month period, and examined the association between changes in volume, history of hypertension, and cognitive training. Between two MRI scans, 49 participants underwent intensive practice in three cognitive domains for 100 consecutive days, whereas 23 control group members performed no laboratory cognitive tasks. Regional volumes of seven brain structures were measured manually and adjusted for intracranial volume. We observed significant mean shrinkage in the lateral prefrontal cortex, the hippocampus, the caudate nucleus, and the cerebellum, but no reliable mean change of the prefrontal white matter, orbital-frontal cortex, and the primary visual cortex. Individual differences in change were reliable in all regions. History of hypertension was associated with greater cerebellar shrinkage. The cerebellum was the only region in which significantly reduced shrinkage was apparent in the experimental group after completion of cognitive training. Thus, in healthy adults, differential brain shrinkage can be observed in a narrow time window, vascular risk may aggravate it, and intensive cognitive activity may have a limited effect on it.

Structural brain plasticity in adult learning and development

Recent research using magnetic resonance imaging has documented changes in the adult human brain's grey matter structure induced by alterations in experiential demands. We review this research and relate it to models of brain plasticity from related strands of research, such as work on animal models. This allows us to generate recommendations and predictions for future research that may advance the understanding of the function, sequential progression, and microstructural nature of experience-dependent changes in regional brain volumes. Informed by recent evidence on adult age differences in structural brain plasticity, we show how understanding learning-related changes in human brain structure can expand our knowledge about adult development and aging. We hope that this review will promote research on the mechanisms regulating experience-dependent structural plasticity of the adult human brain.

Functional Brain Changes Following Cognitive and Motor Skills Training

Background. Functional neuroimaging is increasingly used in rehabilitation research to map the neural mechanisms subserving training targets. These data can inform intervention design and improve evaluation of treatment outcomes. Reliable neural markers may provide standard metrics of treatment impact and allow consideration of behavioral outcomes in the context of functional brain changes. Objective. To identify common patterns of functional brain changes associated with training across a diverse range of intervention protocols. Reliable brain changes could inform development of candidate neural markers to guide intervention research. Methods. Taking a quantitative meta-analytic approach, we review the functional neuroimaging studies of cognitive and motor skills training interventions in healthy young adults (N = 38). Results. Reliable decreases in functional brain activity from pretraining to posttraining were observed in brain regions commonly associated with cognitive control processes, including lateral prefrontal, left anterior inferior parietal lobule, and dorsal anterior cingulate cortex. Training-related increases were observed in the medial prefrontal cortex and posterior cingulate and angular gyrus, core regions of the default network. Activity within the subcortical striatum also showed reliable increases pretraining to posttraining. Conclusions. These data suggest that altered engagement of large-scale, spatially distributed cortical brain networks and subcortical striatal brain regions may serve as candidate neural markers of training interventions. The development of reliable metrics based on activity and functional connectivity among large-scale brain networks may prove fruitful in identifying interactions between domain-general and -specific changes in brain activity that affect behavioral outcomes.

Structural brain changes linked to delayed first language acquisition in congenitally deaf individuals

Early language experience is essential for the development of a high level of linguistic proficiency in adulthood and in a recent functional Magnetic Resonance Imaging (fMRI) experiment, we showed that a delayed acquisition of a first language results in changes in the functional organization of the adult brain (Mayberry et al., 2011). The present study extends the question to explore if delayed acquisition of a first language also modulates the structural development of the brain. To this end, we carried out anatomical MRI in the same group of congenitally deaf individuals who varied in the age of acquisition of a first language, American Sign Language -ASL (Mayberry et al., 2011) and used a neuroanatomical technique, Voxel-Based Morphometry (VBM), to explore changes in gray and white matter concentrations across the brain related to the age of first language acquisition. The results show that delayed acquisition of a first language is associated with changes in tissue concentration in the occipital cortex close to the area that has been found to show functional recruitment during language processing in these deaf individuals with a late age of acquisition. These findings suggest that a lack of early language experience affects not only the functional but also the anatomical organization of the brain.

The future of functionally-related structural change assessment

The brain is continually changing its function and structure in response to changing environmental demands. Magnetic resonance imaging (MRI) methods can be used to repeatedly scan the same individuals over time and in this way have provided powerful tools for assessing such brain change. Functional MRI has provided important insights into changes that occur with learning or recovery but this review will focus on the complementary information that can be provided by structural MRI methods. Structural methods have been powerful in indicating when and where changes occur in both gray and white matter with learning and recovery. However, the measures that we derive from structural MRI are typically ambiguous in biological terms. An important future challenge is to develop methods that will allow us to determine precisely what has changed.

Nicotine facilitates memory consolidation in perceptual learning

Perceptual learning is a special type of non-declarative learning that involves experience-dependent plasticity in sensory cortices. The cholinergic system is known to modulate declarative learning. In particular, reduced levels or efficacy of the neurotransmitter acetylcholine were found to facilitate declarative memory consolidation. However, little is known about the role of the cholinergic system in memory consolidation of non-declarative learning. Here we compared two groups of non-smoking men who learned a visual texture discrimination task (TDT). One group received chewing tobacco containing nicotine for 1 h directly following the TDT training. The other group received a similar tasting control substance without nicotine. Electroencephalographic recordings during substance consumption showed reduced alpha activity and P300 latencies in the nicotine group compared to the control group. When re-tested on the TDT the following day, both groups responded more accurately and more rapidly than during training. These improvements were specific to the retinal location and orientation of the texture elements of the TDT suggesting that learning involved early visual cortex. A group comparison showed that learning effects were more pronounced in the nicotine group than in the control group. These findings suggest that oral consumption of nicotine enhances the efficacy of nicotinic acetylcholine receptors. Our findings further suggest that enhanced efficacy of the cholinergic system facilitates memory consolidation in perceptual learning (and possibly other types of non-declarative learning). In that regard acetylcholine seems to affect consolidation processes in perceptual learning in a different manner than in declarative learning. Alternatively, our findings might reflect dose-dependent cholinergic modulation of memory consolidation. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Experience-dependent structural plasticity in the adult human brain

Contrary to assumptions that changes in brain networks are possible only during crucial periods of development, research in the past decade has supported the idea of a permanently plastic brain. Novel experience, altered afferent input due to environmental changes and learning new skills are now recognized as modulators of brain function and underlying neuroanatomic circuitry. Given findings in experiments with animals and the recent discovery of increases in gray and white matter in the adult human brain as a result of learning, the old concept of cognitive reserve, that is the ability to reinforce brain volume in crucial areas and thus provide a greater threshold for age-dependent deficits, has been reinforced. The challenge we face is to unravel the exact nature of the dynamic structural alterations and, ultimately, to be able to use this knowledge for disease management. Understanding normative changes in brain structure that occur as a result of environmental changes and demands is pivotal to understanding the characteristic ability of the brain to adapt.

Lateralisation of non-metric rhythm

There are contradictory results on lateralisation and localisation of rhythm processing. Our aim was to test whether there is a hemispheric dissociation of metric and non-metric rhythm processing. We created a non-metric rhythm stimulus without a sense of metre and we measured brain activities during passive rhythm perception. A total of 11 healthy, right-handed, native female Hungarian speakers aged 21.3 ± 1.1 were investigated by functional magnetic resonance imaging (fMRI) using a 3T MR scanner. The experimental acoustic stimulus consisted of comprehensive sentences transformed to Morse code, which represent a non-metric rhythm with irregular perceptual accent structure. Activations were found in the right hemisphere, in the posterior parts of the right-sided superior and middle temporal gyri and temporal pole as well as in the orbital part of the right inferior frontal gyrus. Additional activation appeared in the left-sided superior temporal region. Our study suggests that non-metric rhythm with irregular perceptual accents structure is confined to the right hemisphere. Furthermore, a right-lateralised fronto-temporal network extracts the continuously altering temporal structure of the non-metric rhythm.

Imaging learning: the search for a memory trace

Learning is associated with structural changes in the human brain that can be seen and studied by MRI. These changes are observed in gray matter and surprisingly also in white matter tissue. Learning a wide range of skills, from sports, computer games, music, and reading, to abstract intellectual learning, including classroom study, is associated with structural changes in appropriate cortical regions or fiber tracts. The cellular changes underlying modifications of brain tissue during learning include changes in neuronal and glial morphology as well as vascular changes. Both alterations in axon morphology and myelination are thought to contribute to white matter plasticity during learning but to varying degrees depending on age. Structural changes in white matter could promote learning by improving the speed or synchrony of impulse transmission between cortical regions mediating the behavior. Action potentials can stimulate oligodendrocyte development and myelination by at least three known mechanisms that involve signaling molecules between axons and oligodendrocytes, which do not require neurotransmitter release from synapses. Integrating information from cellular/molecular and systems-level research on normal cognitive function, development, and learning is providing new insights into the biological mechanisms of learning and the structural changes produced in the brain.

"Keep calm and carry on": structural correlates of expressive suppression of emotions

There is a growing appreciation that individuals differ systematically in their use of particular emotion regulation strategies. Our aim was to examine the structural correlates of the habitual use of expressive suppression of emotions. Based on our previous research on the voluntary suppression of actions we expected this response-focused emotion regulation strategy to be associated with increased grey matter volume in the dorsomedial prefrontal cortex (dmPFC). On high-resolution MRI scans of 42 college-aged healthy adults we computed optimized voxel-based-morphometry (VBM) to explore the correlation between grey matter volume and inter-individual differences in the tendency to suppress the expression of emotions assessed by means of the Emotion Regulation Questionnaire (Gross & John, 2003). We found a positive correlation between the habitual use of expressive suppression as an emotion regulation strategy and grey matter volume in the dmPFC. No other brain area showed a significant positive or negative correlation with the Emotion Regulation Questionnaire scores. The association between the suppression of expression of emotions and volume in the dmPFC supports the behavioural stability and biological foundation of the concept of this particular emotion regulation strategy within an age-homogenous sample of adults.