Conceptualizing functional neuroplasticity

The therapeutic effects of saikosaponins on depression through the modulation of neuroplasticity: From molecular mechanisms to potential clinical applications

Depression is a major global health issue that urgently requires innovative and precise treatment options. In this context, saikosaponin has emerged as a promising candidate, offering a variety of therapeutic benefits that may be effective in combating depression. This review delves into the multifaceted potential of saikosaponins in alleviating depressive symptoms. We summarized the effects of saikosaponins on structural and functional neuroplasticity, elaborated the regulatory mechanism of saikosaponins in modulating key factors that affect neuroplasticity, such as inflammation, the hypothalamic-pituitary-adrenal (HPA) axis, oxidative stress, and the brain-gut axis. Moreover, this paper highlights existing gaps in current researches and outlines directions for future studies. A detailed plan is provided for the future clinical application of saikosaponins, advocating for more targeted researches to speed up its transition from preclinical trials to clinical practice.

An Agent-Based Model to Reproduce the Boolean Logic Behaviour of Neuronal Self-Organised Communities through Pulse Delay Modulation and Generation of Logic Gates

The human brain is arguably the most complex "machine" to ever exist. Its detailed functioning is yet to be fully understood, let alone modelled. Neurological processes have logical signal-processing and biophysical aspects, and both affect the brain's structure, functioning and adaptation. Mathematical approaches based on both information and graph theory have been extensively used in an attempt to approximate its biological functioning, along with Artificial Intelligence frameworks inspired by its logical functioning. In this article, an approach to model some aspects of the brain learning and signal processing is presented, mimicking the metastability and backpropagation found in the real brain while also accounting for neuroplasticity. Several simulations are carried out with this model to demonstrate how dynamic neuroplasticity, neural inhibition and neuron migration can reshape the brain's logical connectivity to synchronise signal processing and obtain certain target latencies. This work showcases the importance of dynamic logical and biophysical remodelling in brain plasticity. Combining mathematical (agents, graph theory, topology and backpropagation) and biomedical ingredients (metastability, neuroplasticity and migration), these preliminary results prove complex brain phenomena can be reproduced-under pertinent simplifications-via affordable computations, which can be construed as a starting point for more ambitiously accurate simulations.

Altered functional connectivity in default mode network maintains attention task performance in school-age children with frontal lobe tumor

This study examines functional brain network changes in children with frontal lobe tumors (FLT). Ten pediatric FLT patients from Beijing Tiantan Hospital and 20 healthy children were compared in terms of cognitive performance and resting-state functional magnetic resonance imaging (rs-fMRI) connectivity. The FLT group showed lower cognitive performance, particularly in visual and working memory domains, but had comparable attention abilities to the healthy controls. There were notable differences in connectivity between the default mode network (DMN) and sensorimotor network (SMN) in both groups. The FLT group also displayed a significant reduction in local efficiency in the left lateral parietal area within the DMN. Importantly, reduced DMN-SMN connections and increased DMN-lateral prefrontal cortex connectivity may facilitate maintaining attention and memory tasks in FLT children. This study sheds light on how the brains of children with FLT adapt, preserving "normal" attention functions despite frontal lobe damage.

Does right hemisphere compensate for the left in school-age children with large left middle fossa arachnoid cysts?

BACKGROUND

To assess the cognitive function changes and brain network neuroplasticity in school-age children having large (diameter > 5 cm) left middle fossa arachnoid cyst (MFACs).

METHODS

Eleven patients and 22 normal controls (NC) between 6 and 14 years of age were included. The CNS Vital Signs (CNS VS) were administered for cognitive assessment. The differences of cognitive data and functional connectivity (FC) in resting-state functional magnetic resonance imaging (rs-fMRI) were compared between the patient group and the NC group. The correlations between the altered FC and cognitive data in the patient group were assessed.

RESULTS

Patient group had significantly poorer attention (including Complex Attention, Sustained Attention, Simple Attention, Cognitive Flexibility, and Executive Function) and memory function (Visual Memory and Working Memory) than the NC group (uncorrected p-value, p-unc < 0.05). Whole-brain local correlation (LCOR) analysis showed an extensively lower LCOR in the patient group (voxel threshold p-unc < 0.001, cluster-size threshold of false discovery rate adjusted p (p-FDR) < 0.001). Functional connectivity (FC) analysis showed that bilateral frontal and temporal lobes connectivity in the patient group was significantly lower than the NC group (p-FDR < 0.05). Seed-based FC analysis indicated that there was altered FC between the right temporal lobe and the left temporal-parietal/temporal-occipital area (p-FDR < 0.05). In the patient group, most of the altered FC had a negative correlation to the cognitive score, while the FC in the right temporal lobe-left temporal-occipital area positively correlated to Verbal/Visual Memory (r = 0.41-0.60, p-FDR < 0.05). In correlation analysis between clinical data and cognitive score, the only significant result was a low correlation between cyst size and Reaction Time (-0.30--0.36, P-FDR < 0.05).

CONCLUSIONS

School-aged children with large left MFAC showed significantly lower cognitive performance primarily in attention and memory domains. Distinct from neuroplasticity in a unilateral brain lesion, compensation in the healthy hemisphere in MFAC patients was sparse.

Therapeutic Strategies Aimed at Improving Neuroplasticity in Alzheimer Disease

Alzheimer disease (AD) is the most prevalent form of dementia among elderly people. Owing to its varied and multicausal etiopathology, intervention strategies have been highly diverse. Despite ongoing advances in the field, efficient therapies to mitigate AD symptoms or delay their progression are still of limited scope. Neuroplasticity, in broad terms the ability of the brain to modify its structure in response to external stimulation or damage, has received growing attention as a possible therapeutic target, since the disruption of plastic mechanisms in the brain appear to correlate with various forms of cognitive impairment present in AD patients. Several pre-clinical and clinical studies have attempted to enhance neuroplasticity via different mechanisms, for example, regulating glucose or lipid metabolism, targeting the activity of neurotransmitter systems, or addressing neuroinflammation. In this review, we first describe several structural and functional aspects of neuroplasticity. We then focus on the current status of pharmacological approaches to AD stemming from clinical trials targeting neuroplastic mechanisms in AD patients. This is followed by an analysis of analogous pharmacological interventions in animal models, according to their mechanisms of action.

Update on Identification and Treatment of Infants and Toddlers With Suspected Childhood Apraxia of Speech

PURPOSE

The purpose of this tutorial is to (a) provide an updated review of the literature pertaining to proposed early features of childhood apraxia of speech (CAS), (b) discuss the findings of recent treatment studies of infants and toddlers with suspected CAS (sCAS), and (c) present evidence-based strategies and tools that can be used for the identification of and intervention for infants and toddlers with sCAS or at high risk for the disorder.

METHOD

Since Davis and Velleman's (2000) seminal work on assessment and intervention in infants and toddlers with sCAS, limited research has guided clinicians in the complex task of identifying and treating early speech motor difficulties prior to a definitive diagnosis of CAS. Following the structure of Davis and Velleman, we explore the proposed early characteristics of CAS with reference to contemporary research. Next, we describe the limited treatment studies that have investigated intervention for infants and toddlers at risk of or suspected of having CAS. Finally, we present practical suggestions for integrating this knowledge into clinical practice.

CONCLUSIONS

Many of the originally proposed correlates of CAS in infants and toddlers now have research supporting their presence. However, questions remain about the developmental trajectory of the disorder. Although limited in number and restricted by lack of experimental control, emerging treatment studies can help guide clinicians in providing appropriate intervention to infants and toddlers with sCAS who need not wait for a definitive diagnosis to initiate intervention.

A comparative study of the attentional blink of facial expression in deaf and hearing children

The rapid serial visual presentation paradigm was used to investigate differences in the attentional blink between deaf children and hearing children in response to facial expressions of fear and disgust. The results showed that: (1) deaf and hearing children had a higher accuracy rate for T1 with disgustful facial expression than T1 with fear facial expression, (2) There was no significant difference in attentional blink between deaf and hearing children, (3) When T2 appeared at Lag6, the response accuracy of T2 in the disgust T1 condition was lower than that in fear T1 condition. However, no significant difference in T2 at Lag2 was found between the two conditions. The results showed that deaf children and those with hearing were more sensitive to facial expressions of disgust, which captured more attentional resources, and the ability of visual attention of deaf children was not weaker than hearing children.

Early recovery of cognition and brain plasticity after surgery in children with low-grade frontal lobe tumors

Background

Low-grade frontal lobe tumors (LGFLT) can be cured through total resection, but surgical trauma could impair higher-order cognitive function. We aim to characterize the short-term natural cognitive recovery and brain plasticity in surgically-treated pediatric patients with LGFLT.

Methods

Ten pediatric patients with LGFLT were enrolled. Their cognitive function was assessed before the surgery (S0), in the first month post-surgery (S1), and 3-6 months post-surgery (S2), using the CNS Vital Signs battery. DTI and rs-fMRI were performed during the same time periods. Changes of cognition and image metrics between S1>S0 and S2>S1 were analyzed.

Results

The Motor Speed (MotSp) and Reaction Time (RT) scores significantly decreased in S1 and recovered in S2. Rs-fMRI showed decreased functional connectivity (FC) between the bilateral frontal lobes and bilateral caudates, putamina, and pallidi in S1>S0 (voxel threshold p -unc < 0.001 , cluster threshold p -FDR < 0.05 ). In S2>S1, FC recovery was observed in the neighboring frontal cortex areas ( p -unc < 0.001 , p -FDR < 0.05 ). Among them, the FC in the caudates-right inferior frontal gyri was positively correlated to the RT ( p -FDR < 0.05 ). A DTI Tract-based spatial statistics (TBSS) analysis showed decreased fractional anisotropy and axial diffusivity mainly in the corticospinal tracts, cingulum, internal capsule, and external capsule at 0-6 months post-surgery (TFCE- p < 0.05 ). The DTI metrics were not associated with the cognitive data.

Conclusion

Processing speed impairment after an LGFLT resection can recover naturally within 3-6 months in school-age children. Rs-fMRI is more sensitive to short-term brain plasticity than DTI TBSS analysis. "Map expansion" plasticity in the frontal-basal ganglia circuit may contribute to the recovery.

Psychophysiological Assessment of Children with Cerebral Palsy during Robotic-Assisted Gait Training through Infrared Imaging

Cerebral palsy (CP) is a non-progressive neurologic pathology representing a leading cause of spasticity and concerning gait impairments in children. Robotic-assisted gait training (RAGT) is widely employed to treat this pathology to improve children's gait pattern. Importantly, the effectiveness of the therapy is strictly related to the engagement of the patient in the rehabilitation process, which depends on his/her psychophysiological state. The aim of the study is to evaluate the psychophysiological condition of children with CP during RAGT through infrared thermography (IRT), which was acquired during three sessions in one month. A repeated measure ANOVA was performed (i.e., mean value, standard deviation, and sample entropy) extracted from the temperature time course collected over the nose and corrugator, which are known to be indicative of the psychophysiological state of the individual. Concerning the corrugator, significant differences were found for the sample entropy (F (1.477, 5.907) = 6.888; p = 0.033) and for the mean value (F (1.425, 5.7) = 5.88; p = 0.047). Regarding the nose tip, the sample entropy showed significant differences (F (1.134, 4.536) = 11.5; p = 0.041). The findings from this study suggests that this approach can be used to evaluate in a contactless manner the psychophysiological condition of the children with CP during RAGT, allowing to monitor their engagement to the therapy, increasing the benefits of the treatment.

Identification of Functional Cortical Plasticity in Children with Cerebral Palsy Associated to Robotic-Assisted Gait Training: An fNIRS Study

Cerebral palsy (CP) is a non-progressive neurologic condition that causes gait limitations, spasticity, and impaired balance and coordination. Robotic-assisted gait training (RAGT) has become a common rehabilitation tool employed to improve the gait pattern of people with neurological impairments. However, few studies have demonstrated the effectiveness of RAGT in children with CP and its neurological effects through portable neuroimaging techniques, such as functional near-infrared spectroscopy (fNIRS). The aim of the study is to evaluate the neurophysiological processes elicited by RAGT in children with CP through fNIRS, which was acquired during three sessions in one month. The repeated measure ANOVA was applied to the β-values delivered by the General Linear Model (GLM) analysis used for fNIRS data analysis, showing significant differences in the activation of both prefrontal cortex (F (1.652, 6.606) = 7.638; p = 0.022), and sensorimotor cortex (F (1.294, 5.175) = 11.92; p = 0.014) during the different RAGT sessions. In addition, a cross-validated Machine Learning (ML) framework was implemented to estimate the gross motor function measure (GMFM-88) from the GLM β-values, obtaining an estimation with a correlation coefficient r = 0.78. This approach can be used to tailor clinical treatment to each child, improving the effectiveness of rehabilitation for children with CP.

Functional MRI evidence for reorganization of language networks after stroke

In this chapter, we review fMRI evidence for language reorganization in individuals with poststroke aphasia. Several studies in the current literature have utilized fMRI as a tool to understand patterns of functional reorganization in poststroke aphasia. Consistent with previous models that have been proposed to explain the trajectory of language recovery, differential patterns of language processing and language recovery have been identified across individuals with poststroke aphasia in different stages of recovery. Overall, a global network breakdown typically occurs in the early stages of aphasia recovery, followed by normalization in "traditional" left hemisphere language networks. Depending on individual characteristics, right hemisphere regions and bilateral domain-general regions may be further recruited. The main takeaway of this chapter is that poststroke aphasia recovery does not depend on individual neural regions, but rather involves a complex interaction among regions in larger networks. Many of the unresolved issues and contrastive findings in the literature warrant further research with larger groups of participants and standard protocols of fMRI implementation.

Traumatic brain injury augurs ill for prolonged deficits in the brain's structural and functional integrity following controlled cortical impact injury

Previous neuroimaging studies in rodents investigated effects of the controlled cortical impact (CCI) model of traumatic brain injury (TBI) within one-month post-TBI. This study extends this temporal window to monitor the structural–functional alterations from two hours to six months post-injury. Thirty-seven male Sprague–Dawley rats were randomly assigned to TBI and sham groups, which were scanned at two hours, 1, 3, 7, 14, 30, 60 days, and six months following CCI or sham surgery. Structural MRI, diffusion tensor imaging, and resting-state functional magnetic resonance imaging were acquired to assess the dynamic structural, microstructural, and functional connectivity alterations post-TBI. There was a progressive increase in lesion size associated with brain volume loss post-TBI. Furthermore, we observed reduced fractional anisotropy within 24 h and persisted to six months post-TBI, associated with acutely reduced axial diffusivity, and chronic increases in radial diffusivity post-TBI. Moreover, a time-dependent pattern of altered functional connectivity evolved over the six months’ follow-up post-TBI. This study extends the current understanding of the CCI model by confirming the long-term persistence of the altered microstructure and functional connectivity, which may hold a strong translational potential for understanding the long-term sequelae of TBI in humans.

Impact of visual processing skills on reading ability in Chinese deaf children

BACKGROUND

Reading activity involves visual processing in nature. Compared with hearing people, visual processing may be more critical for deaf people. However, much less research has explored the impact of visual processing on the reading ability of deaf children, and the mechanism underlying this relationship is unclear.

AIMS

This study aimed to examine whether and how visual processing skills predict reading ability in elementary school deaf children in China.

METHODS AND PROCEDURES

A total of 118 Chinese deaf children (mean age = 14.60 years) from grades 4-6 were tested on the tasks of visual-graphic processing, visual-orthographic processing, word segmentation, reading comprehension, and reading fluency.

OUTCOMES AND RESULTS

The results showed that after chronological age was controlled, visual-graphic processing and visual-orthographic processing significantly predicted Chinese deaf children's reading ability. Specifically, visual-orthographic processing played a mediating role in the effect of visual-graphic processing on reading ability, whereas word segmentation played a mediating role in the effect of visual-orthographic processing on reading ability. However, the mediating role of word segmentation, as well as the chain mediating effect of visual-orthographic processing and word segmentation in the influence of visual-graphic processing on reading ability, were not significant.

CONCLUSIONS AND IMPLICATIONS

These findings emphasized the importance of visual processing skills in reading activity and offered potential mechanisms underlying the contribution of visual processing skills to reading ability in Chinese deaf children.

Clinical Application of Brain Plasticity in Neurosurgery

Brain plasticity is an ongoing process of reorganization not only on the macroscopic level but also from underlying changes at the cellular and molecular levels of neurons. This evolution has not yet been fully understood. The objective of this paper is to review and understand neuroplasticity through the review of literature, imaging, and intraoperative evidence.

Selective breeding in domestic dogs: How selecting for a short face impacted canine neuroanatomy

The range of cranial morphology seen in domestic dogs (Canis lupus familiaris) is a direct result of thousands of years of selective breeding. This article is the first to investigate how selection for reduced faces in brachycephalic dogs impacted the neuroanatomy of the canine brain through the analysis of endocasts. Previous research has demonstrated global effects on the shape of the bony cranium as the result of these breeding practices; however, these studies have largely focused on the bony structures of the skull and failed to consider the influence of facial reduction on the soft tissues of the brain. We generated endocasts from an existing set of clinically-obtained CT scans representing a variety of dogs with various cranial morphologies. These dogs represented four breeds as well as a comparative sample of dogs of unknown breed. We recorded three-dimensional coordinate data for 31 landmarks representing various gyri, sulci, and other neuroanatomical landmarks that allowed us to analyze differences in shape of the endocasts. Through geometric morphometric analyses, we determined that the endocast shape variance in this sample is correlated with cephalic index, and thus the selection for facial reduction has caused a perceivable effect on canine neuroanatomy. Additionally, we found the majority of the shape variance in the sample to be associated with olfactory anatomy; however, the rest of the morphology also correlates with cephalic index. The results of this article indicate that modern breeding practices and the selection for dogs with short faces have significantly influenced canine neuroanatomy.

Dopamine depletion alters macroscopic network dynamics in Parkinson's disease

Parkinson's disease is primarily characterized by diminished dopaminergic function; however, the impact of these impairments on large-scale brain dynamics remains unclear. It has been difficult to disentangle the direct effects of Parkinson's disease from compensatory changes that reconfigure the functional signature of the whole brain network. To examine the causal role of dopamine depletion in network-level topology, we investigated time-varying network structure in 37 individuals with idiopathic Parkinson's disease, both ON and OFF dopamine replacement therapy, along with 50 age-matched, healthy control subjects using resting state functional MRI. By tracking dynamic network-level topology, we found that the Parkinson's disease OFF state was associated with greater network-level integration than in the ON state. The extent of integration in the OFF state inversely correlated with motor symptom severity, suggesting that a shift toward a more integrated network topology may be a compensatory mechanism associated with preserved motor function in the dopamine depleted OFF state. Furthermore, we were able to demonstrate that measures of both cognitive and brain reserve (i.e. premorbid intelligence and whole brain grey matter volume) had a positive relationship with the relative increase in network integration observed in the dopaminergic OFF state. This suggests that each of these factors plays an important role in promoting network integration in the dopaminergic OFF state. Our findings provide a mechanistic basis for understanding the Parkinson's disease OFF state and provide a further conceptual link with network-level reconfiguration. Together, our results highlight the mechanisms responsible for pathological and compensatory change in Parkinson's disease.

When the brain looks imperfect: An example of neuroplasticity as seen in a patient with arachnoid cysts - a case study

Objective: This study presents a case of a teenager (J.J.) prenatally diagnosed with large arachnoid cysts which did not allow parts of his brain to develop correctly. It aims to establish whether the congenital malformation affected the boy's cognitive development.Method: In order to assess his cognitive development, the authors analyzed J.J.'s medical history, interviewed him and his parents and conducted neuropsychological examination.Results: Despite major parts of his brain undeveloped, the boy achieved average to outstanding scores in all tests.Conclusions: The scores achieved by J.J. suggest that normal development of cognitive abilities is possible even for a person whose central nervous system differs structurally from what is expected in a healthy subject.

The Neural and Behavioral Correlates of Anomia Recovery following Personalized Observation, Execution, and Mental Imagery Therapy: A Proof of Concept

The impact of sensorimotor strategies on aphasia recovery has rarely been explored. This paper reports on the efficacy of personalized observation, execution, and mental imagery (POEM) therapy, a new approach designed to integrate sensorimotor and language-based strategies to treat verb anomia, a frequent aphasia sign. Two participants with verb anomia were followed up in a pre-/posttherapy fMRI study. POEM was administered in a massed stimulation schedule, with personalized stimuli, resulting in significant improvement in both participants, with both trained and untrained items. Given that the latter finding is rarely reported in the literature, the evidence suggests that POEM favors the implementation of a word retrieval strategy that can be integrated and generalized. Changes in fMRI patterns following POEM reflect a reduction in the number of recruited areas supporting naming and the recruitment of brain areas that belong to the language and mirror neuron systems. The data provide evidence on the efficacy of POEM for verb anomia, while pointing to the added value of combined language and sensorimotor strategies for recovery from verb anomia, contributing to the consolidation of a word retrieval strategy that can be better generalized to untrained words. Future studies with a larger sample of participants are required to further explore this avenue.

Stuttering treatment and brain research in adults: A still unfolding relationship

PURPOSE

Brain imaging and brain stimulation procedures have now been used for more than two decades to investigate the neural systems that contribute to the occurrence of stuttering in adults, and to identify processes that might enhance recovery from stuttering. The purpose of this paper is to review the extent to which these dual lines of research with adults who stutter have intersected and whether they are contributing towards the alleviation of this impairment.

METHOD

Several areas of research are reviewed in order to determine whether research on the neurology of stuttering is showing any potential for advancing the treatment of this communication disorder: (a) attempts to discover the neurology of stuttering, (b) neural changes associated with treated recovery, and (c) direct neural intervention.

RESULTS AND CONCLUSIONS

Although much has been learned about the neural underpinnings of stuttering, little research in any of the reviewed areas has thus far contributed to the advancement of stuttering treatment. Much of the research on the neurology of stuttering that does have therapy potential has been largely driven by a speech-motor model that is designed to account for the efficacy of fluency-inducing strategies and strategies that have been shown to yield therapy benefits. Investigations on methods that will induce neuroplasticity are overdue. Strategies profitable with other disorders have only occasionally been employed. However, there are signs that investigations on the neurology of adults who have recovered from stuttering are slowly being recognized for their potential in this regard.

Neuroplasticity and the logic of cognitive neuropsychology

More than thirty years ago, Alfonso Caramazza laid out assumptions for drawing inferences about the undamaged cognitive system from individuals with brain damage. Since then, these assumptions have been challenged including the transparency or subtractivity assumption, that the cognitive system does not reorganize following brain damage. It has been repeatedly demonstrated that brains are highly plastic. However, there is no clear connection between brain plasticity and cognitive reorganization. Brain plasticity research does not require a rethinking of the core logic of cognitive neuropsychology. Differences in task-based activation between damaged and undamaged brains provide little insight into the cognitive architectures of brain-damaged patients. Theory and methods are needed to understand cognitive neuroplasticity, or how neural reorganization that follows brain damage relates to reorganization of functions. We discuss alternative types of cognitive neuroplasticity that may occur in damaged brains and consider how they impact the basic logic of cognitive neuropsychology.

From Serotonin to Neuroplasticity: Evolvement of Theories for Major Depressive Disorder

The serotonin (5-HT) hypothesis of depression has played an important role in the history of psychiatry, yet it has also been criticized for the delayed onset and inadequate efficacy of selective serotonin reuptake inhibitors (SSRIs). With evolvement of neuroscience, the neuroplasticity hypothesis of major depressive disorder (MDD) has been proposed and may provide a better framework for clarification the pathogenesis of MDD and antidepressant efficacy. In this article, we first summarized the evidence challenging the monoamine hypothesis and proposed that the antidepressant efficacy of SSRIs is not derived from elevated monoamine (5-HT, noradrenaline (NE), or dopamine (DA)) concentration or monoamine neurotransmission. Second, we reviewed the role of stress in the pathogenesis of MDD and gave a brief introduction to the neuroplasticity hypothesis of MDD. Third, we explored the possible mechanisms underlying the antidepressant efficacy of typical antidepressants in the context of neuroplasticity theory. Fourth, we tried to provide an explanatory framework for the significant difference in onset of efficacy between typical antidepressants and ketamine. Finally, we provided a brief summarization about this review article and some perspectives for future studies.

Plasticity in the Working Memory System: Life Span Changes and Response to Injury

Working memory acts as a key bridge between perception, long-term memory, and action. The brain regions, connections, and neurotransmitters that underlie working memory undergo dramatic plastic changes during the life span, and in response to injury. Early life reliance on deep gray matter structures fades during adolescence as increasing reliance on prefrontal and parietal cortex accompanies the development of executive aspects of working memory. The rise and fall of working memory capacity and executive functions parallels the development and loss of neurotransmitter function in frontal cortical areas. Of the affected neurotransmitters, dopamine and acetylcholine modulate excitatory-inhibitory circuits that underlie working memory, are important for plasticity in the system, and are affected following preterm birth and adult brain injury. Pharmacological interventions to promote recovery of working memory abilities have had limited success, but hold promise if used in combination with behavioral training and brain stimulation. The intense study of working memory in a range of species, ages and following injuries has led to better understanding of the intrinsic plasticity mechanisms in the working memory system. The challenge now is to guide these mechanisms to better improve or restore working memory function.

Good night, sleep tight: The effects of sleep deprivation on spatial associative learning in zebrafish

Learning and memory are vital to an animal's survival, and numerous factors can disrupt cognitive performance. Sleep is an evolutionarily conserved physiological process known to be important for the consolidation of learning and memory. The zebrafish has emerged as a powerful model organism sharing organizational and functional characteristics with other vertebrates, providing great translational relevance. In our study, we used a simple spatial associative learning task to quantify the effects of sleep deprivation (partial vs. total) on learning performance in zebrafish, using an animated conspecific shoal image as a reward. Control animals maintained on a regular light:dark cycle were able to acquire the association between the unconditioned and conditioned stimulus, reinforcing zebrafish as a valid and reliable model for appetitive conditioning tasks. Notably, sleep deprivation did not alter the perception of and response to the conspecific image. In contrast, although partial sleep deprivation did not impair cognitive performance, total sleep deprivation significantly impaired performance on the associative learning task. Our results suggest that sleep is important for learning and memory, and that the effects of sleep deprivation on these processes can be investigated in zebrafish.

The Cognitive Neuroplasticity of Reading Recovery following Chronic Stroke: A Representational Similarity Analysis Approach

Damage to certain left hemisphere regions leads to reading impairments, at least acutely, though some individuals eventually recover reading. Previous neuroimaging studies have shown a relationship between reading recovery and increases in contralesional and perilesional activation during word reading tasks, relative to controls. Questions remain about how to interpret these changes in activation. Do these changes reflect functional take-over, a reorganization of functions in the damaged brain? Or do they reveal compensatory masquerade or the use of alternative neural pathways to reading that are available in both patients and controls? We address these questions by studying a single individual, CH, who has made a partial recovery of reading familiar words following stroke. We use an fMRI analysis technique, representational similarity analysis (RSA), which allows us to decode cognitive function from distributed patterns of neural activity. Relative to controls, we find that CH shows a shift from visual to orthographic processing in contralesional regions, with a marginally significant result in perilesional regions as well. This pattern supports a contralesional reorganization of orthographic processing following stroke. More generally, these analyses demonstrate how powerful RSA can be for mapping the neural plasticity of language function.

Maladaptive Plasticity in Aphasia: Brain Activation Maps Underlying Verb Retrieval Errors

Anomia, or impaired word retrieval, is the most widespread symptom of aphasia, an acquired language impairment secondary to brain damage. In the last decades, functional neuroimaging techniques have enabled studying the neural basis underlying anomia and its recovery. The present study aimed to explore maladaptive plasticity in persistent verb anomia, in three male participants with chronic nonfluent aphasia. Brain activation maps associated with semantic verb paraphasia occurring within an oral picture-naming task were identified with an event-related fMRI paradigm. These maps were compared with those obtained in our previous study examining adaptive plasticity (i.e., successful verb naming) in the same participants. The results show that activation patterns related to semantic verb paraphasia and successful verb naming comprise a number of common areas, contributing to both maladaptive and adaptive neuroplasticity mechanisms. This finding suggests that the segregation of brain areas provides only a partial view of the neural basis of verb anomia and successful verb naming. Therefore, it indicates the importance of network approaches which may better capture the complexity of maladaptive and adaptive neuroplasticity mechanisms in anomia recovery.

The relationships between the amount of spared tissue, percent signal change, and accuracy in semantic processing in aphasia

Recovery from aphasia, loss of language following a cerebrovascular incident (stroke), is a complex process involving both left and right hemispheric regions. In our study, we analyzed the relationships between semantic processing behavioral data, lesion size and location, and percent signal change from functional magnetic resonance imaging (fMRI) data. This study included 14 persons with aphasia in the chronic stage of recovery (six or more months post stroke), along with normal controls, who performed semantic processing tasks of determining whether a written semantic feature matched a picture or whether two written words were related. Using region of interest (ROI) analysis, we found that left inferior frontal gyrus pars opercularis and pars triangularis, despite significant damage, were the only regions to correlate with behavioral accuracy. Additionally, bilateral frontal regions including superior frontal gyrus, middle frontal gyrus, and anterior cingulate appear to serve as an assistive network in the case of damage to traditional language regions that include inferior frontal gyrus, middle temporal gyrus, supramarginal gyrus, and angular gyrus. Right hemisphere posterior regions including right middle temporal gyrus, right supramarginal gyrus, and right angular gyrus are engaged in the case of extensive damage to left hemisphere language regions. Additionally, right inferior frontal gyrus pars orbitalis is presumed to serve a monitoring function. These results reinforce the importance of the left hemisphere in language processing in aphasia, and provide a framework for the relative importance of left and right language regions in the brain.

Scientific and conceptual flaws of coercive treatment models in addiction

In conceptual debates on addiction, neurobiological research has been used to support the idea that addicted drug users lack control over their addiction-related actions. In some interpretations, this has led to coercive treatment models, in which, the purpose is to 'restore' control. However, neurobiological studies that go beyond what is typically presented in conceptual debates paint a different story. In particular, they indicate that though addiction has neurobiological manifestations that make the addictive behaviour difficult to control, it is possible for individuals to reverse these manifestations through their own efforts. Thus, addicted individuals should not be considered incapable of making choices voluntarily, simply on the basis that addiction has neurobiological manifestations, and coercive treatment models of addiction should be reconsidered in this respect.

What do patients with epilepsy tell us about language dynamics? A review of fMRI studies

The objective of this review is to resume major neuroimaging findings on language organization and plasticity in patients with focal and refractory epilepsy, to discuss the effect of modulatory variables that should be considered alongside patterns of reorganization, and to propose possible models of language reorganization. The focal and refractory epilepsy provides a real opportunity to investigate various types of language reorganization in different conditions. The 'chronic' condition (induced by the epileptogenic zone or EZ) is associated with either recruitment of homologous regions of the opposite hemisphere or recruitment of intrahemispheric, nonlinguistic regions. In the 'acute' condition (neurosurgery and EZ resection), the initial interhemispheric shift (induced by the chronic EZ) could follow a reverse direction, back to the initial hemisphere. These different patterns depend on several modulatory factors and are associated with various levels of language performance. As a neuroimaging tool, functional magnetic resonance imaging enables the detailed investigation of both hemispheres simultaneously and allows for comparison with healthy controls, potentially creating a more comprehensive and more realistic picture of brain-language relations. Importantly, functional neuroimaging approaches demonstrate a good degree of concordance on a theoretical level, but also a considerable degree of individual variability, attesting to the clinical importance with these methods to establish, empirically, language localization in individual patients. Overall, the unique features of epilepsy, combined with ongoing advances in technology, promise further improvement in understanding of language substrate.

Training-induced plasticity of the social brain in autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is linked to social brain activity and facial affect recognition (FAR).

AIMS

To examine social brain plasticity in ASD.

METHOD

Using FAR tests and functional magnetic resonance imaging tasks for FAR, we compared 32 individuals with ASD and 25 controls. Subsequently, the participants with ASD were assigned to FAR computer-aided cognitive training or a control group.

RESULTS

The ASD group performed more poorly than controls on explicit behavioural FAR tests. In the scanner, during implicit FAR, the amygdala, fusiform gyrus and other regions of the social brain were less activated bilaterally. The training group improved on behavioural FAR tests, and cerebral response to implicit affect processing tasks increased bilaterally post-training in the social brain.

CONCLUSIONS

Individuals with ASD show FAR impairments associated with hypoactivation of the social brain. Computer-based training improves explicit FAR and neuronal responses during implicit FAR, indicating neuroplasticity in the social brain in ASD.

Central auditory processing in patients with spinocerebellar ataxia

BACKGROUND

Autosomal dominant spinocerebellar ataxias (SCAs) are a group of rare and heterogeneous neurodegenerative diseases characterized by the presence of progressive cerebellar ataxia. Although the symptomatology of SCAs is well known, information regarding central auditory functioning in these patients is lacking. Therefore, we assessed the central auditory processing disorders (CAPD) in patients with different subtypes of SCA.

METHODS

In a retrospective cross-sectional study, we subjected 43 patients with SCAs to otorhinolaryngological, audiological, Brainstem Auditory Evoked Potential (BAEP) and acoustic immittance evaluations as well as CAPD tests, namely the Standard Spondaic Word (SSW) and the Random Gap Detection Test (RGDT).

RESULTS

Most patients (83.7%) reported an imbalance when walking; many reported difficulty speaking (48.8%), dizziness (41.8%), and dysphagia (39.5%). In the audiometric test, 14/43 patients (32.5%) presented alterations, including 4/12 patients with SCA3 (33.3%), 1/8 patients with SCA2 (12.5%), 1/1 patient with SCA4 (100%), 1/1 patient with SCA6 (100%), 1/1 patient with SCA7 (100%), 3/6 patients with SCA10 (50%), and 3/14 patients with an undetermined type of SCA (21.4%). In the BAEP test, 20/43 patients (46.5%) presented alterations (11.6% na orelha esquerda e 34.9% bilateralmente), including 7/12 patients with SCA3 (58.3%), 5/8 patients with SCA2 (62.5%), 1/1 patient with SCA4 (100%), 1/1 patient with SCA6 (100%), 1/1 patient with SCA7 (100%), 4/6 patients with SCA10 (66.7%), and 2/14 patients with an undetermined type of SCA (14.2%). In the SSW, 22/40 patients (55%) presented alterations (2.5% in the right ear, 15% in the left ear, and 37.5% bilaterally), including 6/10 patients (60%) with SCA3, 3/8 (37.5%) with SCA2, 1/1 (100%) with SCA4, 1/1 (100%) with SCA6, 1/1 (100%) with SCA7, 4/5 (80%) with SCA10, and 8/14 (57.1%) with an undetermined type SCA. For the RGDT, 30/40 patients (75%) presented alterations, including 8/10 (80%) with SCA3, 6/8 (75%) with SCA2, 1/1 (100%) with SCA4, 1/1 (100%) with SCA6, 1/1 (100%) with SCA7, 4/5 (80%) with SCA10, and 9/14 (64.3%) with an undetermined type of SCA. In immittance testing, 19/43 patients (44.1%) presented alterations, including 6/12 (50%) with SCA3, 4/8 (50%) with SCA2, 1/1 (100%) with SCA4, 1/1 (100%) with SCA6, 1/1 (100%) with SCA7, 2/6 (33.3%) with SCA10, and 4/14 (28.6%) with an undetermined type of SCA.

CONCLUSIONS

A majority of patients exhibited SSW test deficits, with a predominance of bilateralism, and three-fourths had impaired RGDT performance, pointing to difficulties with binaural integration and temporal resolution. Assessment of CAPD is important for therapeutic follow ups in patients with SCA.

An fMRI investigation of the effects of attempted naming on word retrieval in aphasia

In healthy controls, picture naming performance can be facilitated by a single prior exposure to the same picture (“priming”). This priming phenomenon is utilized in the treatment of aphasia, which often includes repeated picture naming as part of a therapeutic task. The current study sought to determine whether single and/or multiple exposures facilitate subsequent naming in aphasia and whether such facilitatory effects act through normal priming mechanisms. A functional magnetic resonance imaging paradigm was employed to explore the beneficial effects of attempted naming in two individuals with aphasia and a control group. The timing and number of prior exposures was manipulated, with investigation of both short-term effects (single prior exposure over a period of minutes) and long-term effects (multiple presentations over a period of days). Following attempted naming, both short-term and long-term facilitated items showed improvement for controls, while only the long-term condition showed benefits at a behavioral level for the participants with aphasia. At a neural level, effects of long-term facilitation were noted in the left precuneus for one participant with aphasia, a result also identified for the equivalent contrast in controls. It appears that multiple attempts are required to improve naming performance in the presence of anomia and that for some individuals with aphasia the source of facilitation may be similar to unimpaired mechanisms engaged outside the language network.

Changes of functional connectivity in the left frontoparietal network following aphasic stroke

Language is an essential higher cognitive function supported by large-scale brain networks. In this study, we investigated functional connectivity changes in the left frontoparietal network (LFPN), a language-cognition related brain network in aphasic patients. We enrolled 13 aphasic patients who had undergone a stroke in the left hemisphere and age-, gender-, educational level-matched controls and analyzed the data by integrating independent component analysis (ICA) with a network connectivity analysis method. Resting state functional magnetic resonance imaging (fMRI) and clinical evaluation of language function were assessed at two stages: 1 and 2 months after stroke onset. We found reduced functional connectivity between the LFPN and the right middle frontal cortex, medial frontal cortex, and right inferior frontal cortex in aphasic patients as compared to controls. Correlation analysis showed that stronger functional connectivity between the LFPN and the right middle frontal cortex and medial frontal cortex coincided with more preserved language comprehension ability after stroke. Network connectivity analysis showed reduced LFPN connectivity as indicated by the mean network connectivity index of key regions in the LFPN of aphasic patients. The decreased LFPN connectivity in stroke patients was significantly associated with the impairment of language function in their comprehension ability. We also found significant association between recovery of comprehension ability and the mean changes in intrinsic LFPN connectivity. Our findings suggest that brain lesions may influence language comprehension by altering functional connectivity between regions and that the patterns of abnormal functional connectivity may contribute to the recovery of language deficits.

Auditory evoked potentials: predicting speech therapy outcomes in children with phonological disorders

OBJECTIVES

This study investigated whether neurophysiologic responses (auditory evoked potentials) differ between typically developed children and children with phonological disorders and whether these responses are modified in children with phonological disorders after speech therapy.

METHODS

The participants included 24 typically developing children (Control Group, mean age: eight years and ten months) and 23 children clinically diagnosed with phonological disorders (Study Group, mean age: eight years and eleven months). Additionally, 12 study group children were enrolled in speech therapy (Study Group 1), and 11 were not enrolled in speech therapy (Study Group 2). The subjects were submitted to the following procedures: conventional audiological, auditory brainstem response, auditory middle-latency response, and P300 assessments. All participants presented with normal hearing thresholds. The study group 1 subjects were reassessed after 12 speech therapy sessions, and the study group 2 subjects were reassessed 3 months after the initial assessment. Electrophysiological results were compared between the groups.

RESULTS

Latency differences were observed between the groups (the control and study groups) regarding the auditory brainstem response and the P300 tests. Additionally, the P300 responses improved in the study group 1 children after speech therapy.

CONCLUSION

The findings suggest that children with phonological disorders have impaired auditory brainstem and cortical region pathways that may benefit from speech therapy.

A functional MRI study of the relationship between naming treatment outcomes and resting state functional connectivity in post-stroke aphasia

BACKGROUND

The majority of studies investigating the neural mechanisms underlying treatment in people with aphasia have examined task-based brain activity. However, the use of resting-state fMRI may provide another method of examining the brain mechanisms responsible for treatment-induced recovery, and allows for investigation into connectivity within complex functional networks

METHODS

Eight people with aphasia underwent 12 treatment sessions that aimed to improve object naming. Half the sessions employed a phonologically-based task, and half the sessions employed a semantic-based task, with resting-state fMRI conducted pre- and post-treatment. Brain regions in which the amplitude of low frequency fluctuations (ALFF) correlated with treatment outcomes were used as seeds for functional connectivity (FC) analysis. FC maps were compared from pre- to post-treatment, as well as with a group of 12 healthy older controls

RESULTS

Pre-treatment ALFF in the right middle temporal gyrus (MTG) correlated with greater outcomes for the phonological treatment, with a shift to the left MTG and supramarginal gyrus, as well as the right inferior frontal gyrus, post-treatment. When compared to controls, participants with aphasia showed both normalization and up-regulation of connectivity within language networks post-treatment, predominantly in the left hemisphere

CONCLUSIONS

The results provide preliminary evidence that treatments for naming impairments affect the FC of language networks, and may aid in understanding the neural mechanisms underlying the rehabilitation of language post-stroke.

Distinguishable neurofunctional effects of task practice and item practice in picture naming: a BOLD fMRI study in healthy subjects

Practice of language tasks results in improved performance and BOLD signal changes. We distinguish changes correlated with repeated exposure to a picture naming task, from changes associated with naming specific items trained during practice. Task practice affected trained and untrained items, yielding left-sided BOLD deactivations in extrastriate, prefrontal and superior temporal areas (consistent with their putative role in perceptual priming, articulatory planning and phonological lexical retrieval, respectively). Item practice effects were restricted to trained words. There was deactivation in left posterior fusiform (supporting its role in accessing structural object representations), anterior cingulate and left insular/inferior frontal cortices (consistent with their role in processing low-frequency words). Central precuneus and posterior cingulate were hyperactivated (consistent with their putative role in episodic memory for trained items, probably due to functional connections with language areas). In healthy subjects, naming practice modifies stored linguistic representations, but mostly affects ease of access to trained words.

Digital media, the developing brain and the interpretive plasticity of neuroplasticity

The use and misuse of digital technologies among adolescents has been the focus of fiery debates among parents, educators, policy-makers and in the media. Recently, these debates have become shaped by emerging data from cognitive neuroscience on the development of the adolescent brain and cognition. "Neuroplasticity" has functioned as a powerful metaphor in arguments both for and against the pervasiveness of digital media cultures that increasingly characterize teenage life. In this paper, we propose that the debates concerning adolescents are the meeting point of two major social anxieties both of which are characterized by the threat of "abnormal" (social) behaviour: existing moral panics about adolescent behaviour in general and the growing alarm about intense, addictive, and widespread media consumption in modern societies. Neuroscience supports these fears but the same kinds of evidence are used to challenge these fears and reframe them in positive terms. Here, we analyze discourses about digital media, the Internet, and the adolescent brain in the scientific and lay literature. We argue that while the evidential basis is thin and ambiguous, it has immense social influence. We conclude by suggesting how we might move beyond the poles of neuro-alarmism and neuro-enthusiasm. By analyzing the neurological adolescent in the digital age as a socially extended mind, firstly, in the sense that adolescent cognition is distributed across the brain, body, and digital media tools and secondly, by viewing adolescent cognition as enabled and transformed by the institution of neuroscience, we aim to displace the normative terms of current debates.

Neurocognitive brain response to transient impairment of Wernicke's area

This study examined how the brain system adapts and reconfigures its information processing capabilities to maintain cognitive performance after a key cortical center [left posterior superior temporal gyrus (LSTGp)] is temporarily impaired during the performance of a language comprehension task. By applying repetitive transcranial magnetic stimulation (rTMS) to LSTGp and concurrently assessing the brain response with functional magnetic resonance imaging, we found that adaptation consisted of 1) increased synchronization between compensating regions coupled with a decrease in synchronization within the primary language network and 2) a decrease in activation at the rTMS site as well as in distal regions, followed by their recovery. The compensatory synchronization included 3 centers: The contralateral homolog (RSTGp) of the area receiving rTMS, areas adjacent to the rTMS site, and a region involved in discourse monitoring (medial frontal gyrus). This approach reveals some principles of network-level adaptation to trauma with potential application to traumatic brain injury, stroke, and seizure.

Brain activity in adults who stutter: similarities across speaking tasks and correlations with stuttering frequency and speaking rate

Many differences in brain activity have been reported between persons who stutter (PWS) and typically fluent controls during oral reading tasks. An earlier meta-analysis of imaging studies identified stutter-related regions, but recent studies report less agreement with those regions. A PET study on adult dextral PWS (n=18) and matched fluent controls (CONT, n=12) is reported that used both oral reading and monologue tasks. After correcting for speech rate differences between the groups the task-activation differences were surprisingly small. For both analyses only some regions previously considered stutter-related were more activated in the PWS group than in the CONT group, and these were also activated during eyes-closed rest (ECR). In the PWS group, stuttering frequency was correlated with cortico-striatal-thalamic circuit activity in both speaking tasks. The neuroimaging findings for the PWS group, relative to the CONT group, appear consistent with neuroanatomic abnormalities being increasingly reported among PWS.

Potenciais evocados auditivos de longa latência em crianças com transtorno fonológico

TEMA: potenciais evocados auditivos em crianças com transtorno fonológico. OBJETIVO: caracterizar os resultados dos Potenciais Evocados Auditivos de Longa Latência (PEALL) N1, P2, N2 e P300 obtidos em crianças com transtorno fonológico, e verificar a evolução dos resultados destes potenciais frente à terapia fonoaudiológica. MÉTODO: foram avaliadas, por meio da avaliação audiológica básica e dos PEALL, 25 crianças sem transtorno fonológico (grupo controle) e 41 com transtorno fonológico (grupo estudo), estas divididas em dois subgrupos: 22 formaram o subgrupo estudo A, que foram submetidas a 12 sessões de terapia fonoaudiológica e reavaliadas audiologicamente após este período e 19 o subgrupo estudo B, que foram reavaliadas após três meses da avaliação inicial. RESULTADOS: observaram-se diferenças estatisticamente significantes entre os grupos controle e estudo para as latências de P2 e P300 e amplitude do P300. Na comparação entre as duas avaliações audiológicas, não foram observadas diferenças significantes para as latências em ambos os subgrupos, e verificou-se diferença significante para as amplitudes do P300 (subgrupo estudo A) e do P2/N2 (subgrupo estudo B). O P300 apresentou maior porcentagem de resultados alterados no grupo estudo, com predomínio do aumento de latência. Após terapia, observou-se melhora nos resultados para todos os componentes. Não existiu associação entre a evolução dos resultados dos PEALL e o histórico de otite, bem como correlação com o Percentage of Consonants Correct-Revised. CONCLUSÃO: crianças com transtorno fonológico apresentam alterações no P300, sugerindo alteração no processamento auditivo, apresentando melhora nos resultados de todos os componentes dos PEALL frente à terapia fonoaudiológica.

Christfried Jakob's 1921 Theory of the Gnoses and Praxes as fundamental factors in cerebral cortical dynamics

This study aims at reviving an important contribution by the pioneer neurobiologist and neurophilosopher Christfried Jakob (1866-1956) to the understanding of higher cortical functions. Jakob studied cortical dynamics at multiple levels by comparing gnoses and praxes and their corresponding pathological states, i.e. the agnosias and the apraxias. We herein provide a complete English translation of Jakob's original Spanish article dating to 1921, and further consider some key points under the scope of the neuropsychological knowledge available then, and the research evidence available 90 years later.

Neural mechanisms of verb argument structure processing in agrammatic aphasic and healthy age-matched listeners

Processing of lexical verbs involves automatic access to argument structure entries entailed within the verb's representation. Recent neuroimaging studies with young normal listeners suggest that this involves bilateral posterior peri-sylvian tissue, with graded activation in these regions on the basis of argument structure complexity. The aim of the present study was to examine the neural mechanisms of verb processing using fMRI in older normal volunteers and patients with stroke-induced agrammatic aphasia, a syndrome in which verb, as compared to noun, production often is selectively impaired, but verb comprehension in both on-line and off-line tasks is spared. Fourteen healthy listeners and five age-matched aphasic patients performed a lexical decision task, which examined verb processing by argument structure complexity, namely, one-argument [i.e., intransitive (v1)], two-argument [i.e., transitive (v2)], and three-argument (v3) verbs. Results for the age-matched listeners largely replicated those for younger participants studied by Thompson et al. [Thompson, C. K., Bonakdarpour, B., Fix, S. C., Blumenfeld, H. K., Parrish, T. B., Gitelman, D. R., et al. Neural correlates of verb argument structure processing. Journal of Cognitive Neuroscience, 19, 1753-1767, 2007]: v3 - v1 comparisons showed activation of the angular gyrus in both hemispheres and this same heteromodal region was activated in the left hemisphere in the (v2 + v3) - v1 contrast. Similar results were derived for the agrammatic aphasic patients, however, activation was unilateral (in the right hemisphere for three participants) rather than bilateral, likely because these patients' lesions extended to the left temporo-parietal region. All performed the task with high accuracy and, despite differences in lesion site and extent, they recruited spared tissue in the same regions as healthy subjects. Consistent with psycholinguistic models of sentence processing, these findings indicate that the posterior language network is engaged for processing verb argument structure and is crucial for semantic integration of argument structure information.