Cortical and behavioral correlates of alexia in primary progressive aphasia and Alzheimer's disease.

The underlying causes of reading impairment in neurodegenerative disease are not well understood. The current study seeks to determine the causes of surface alexia and phonological alexia in primary progressive aphasia (PPA) and typical (amnestic) Alzheimer's disease (AD). Participants included 24 with the logopenic variant (lvPPA), 17 with the nonfluent/agrammatic variant (nfvPPA), 12 with the semantic variant (svPPA), 19 with unclassifiable PPA (uPPA), and 16 with AD.

Functional partitioning of sentence processing and emotional prosody in the right perisylvian cortex after perinatal stroke.

In healthy adults different language abilities-sentence processing versus emotional prosody-are supported by the left (LH) versus the right hemisphere (RH), respectively. However, after LH stroke in infancy, RH regions often support both abilities with normal outcomes. This finding raises an important question: How does the functional map of RH regions change to support both emotional prosody and also typically left-lateralized language functions after an early LH stroke? Does sentence processing simply become reflected into RH frontotemporal regions and overlap with emotional prosody processing? Or do these functions overlap less than would be expected with simple mirroring? In the current work we used task fMRI to examine precisely how sentence processing and emotional prosody processing are both organized in the intact RH of individuals who suffered a large LH perinatal arterial ischemic stroke (LHPS participants).

Evidence from aphasia suggests a bidirectional relationship between inner speech and executive function.

Research over the past several decades has revealed that non-linguistic cognitive impairments can appear alongside language deficits in individuals with aphasia. One vulnerable cognitive domain is executive function, an umbrella term for the higher-level cognitive processes that allow us to direct our behavior towards a goal. Studies in healthy adults reveal that executive function abilities are supported by inner speech, the ability to use language silently in one's head.

Correction: Cingulate transcranial direct current stimulation in adults with HIV.

[This corrects the article DOI: 10.1371/journal.pone.

Rapid auditory and phonemic processing relies on the left planum temporale.

After initial bilateral acoustic processing of the speech signal, much of the subsequent language processing is left-lateralized. The reason for this lateralization remains an open question. Prevailing hypotheses describe a left hemisphere (LH) advantage for rapidly unfolding information-such as the segmental (e.

Evaluating circumlocution in naming as a predictor of communicative informativeness and efficiency in discourse.

Background: Discourse analyses yield quantitative measures of functional communication in aphasia. However, they are historically underutilized in clinical settings. Confrontation naming assessments are used widely clinically and have been used to estimate discourse-level production.

The neuroanatomy of developmental language disorder: a systematic review and meta-analysis.

Developmental language disorder (DLD) is a common neurodevelopmental disorder with adverse impacts that continue into adulthood. However, its neural bases remain unclear. Here we address this gap by systematically identifying and quantitatively synthesizing neuroanatomical studies of DLD using co-localization likelihood estimation, a recently developed neuroanatomical meta-analytic technique.

Functional partitioning of sentence processing and emotional prosody in the right perisylvian cortex after perinatal stroke.

In healthy adults different language abilities-sentence processing versus emotional prosody-are supported by the left (LH) versus the right hemisphere (RH), respectively. However, after LH stroke in infancy, RH regions support both abilities with normal outcomes. We investigated how these abilities co-exist in RH regions after LH perinatal stroke by evaluating the overlap in the activation between two fMRI tasks that probed auditory sentence processing and emotional prosody processing.

Baseline Conceptual-Semantic Impairment Predicts Longitudinal Treatment Effects for Anomia in Primary Progressive Aphasia and Alzheimer's Disease.

Background: An individual's diagnostic subtype may fail to predict the efficacy of a given type of treatment for anomia. Classification by conceptual-semantic impairment may be more informative.

Aims: This study examined the effects of conceptual-semantic impairment and diagnostic subtype on anomia treatment effects in primary progressive aphasia (PPA) and Alzheimer's disease (AD).

Rethinking Remapping: Circuit Mechanisms of Recovery after Stroke.

Stroke is one of the most common causes of disability, and there are few treatments that can improve recovery after stroke. Therapeutic development has been hindered because of a lack of understanding of precisely how neural circuits are affected by stroke, and how these circuits change to mediate recovery. Indeed, some of the hypotheses for how the CNS changes to mediate recovery, including remapping, redundancy, and diaschisis, date to more than a century ago.

Listening to Yourself and Watching Your Tongue: Distinct Abilities and Brain Regions for Monitoring Semantic and Phonological Speech Errors.

Despite the many mistakes we make while speaking, people can effectively communicate because we monitor our speech errors. However, the cognitive abilities and brain structures that support speech error monitoring are unclear. There may be different abilities and brain regions that support monitoring phonological speech errors versus monitoring semantic speech errors.

Functional anomaly mapping lateralizes temporal lobe epilepsy with high accuracy in individual patients.

Mesial temporal lobe epilepsy (mTLE) is associated with variable dysfunction beyond the temporal lobe. We used functional anomaly mapping (FAM), a multivariate machine learning approach to resting state fMRI analysis to measure subcortical and cortical functional aberrations in patients with mTLE. We also examined the value of individual FAM in lateralizing the hemisphere of seizure onset in mTLE patients.

Effects of healthy aging and left hemisphere stroke on statistical language learning.

Spoken sentences are continuous streams of sound, without reliable acoustic cues to word boundaries. We have previously proposed that language learners identify words via an implicit statistical learning mechanism that computes transitional probabilities between syllables. Neuroimaging studies in healthy young adults associate this learning with left inferior frontal gyrus, left arcuate fasciculus, and bilateral striatum.

Aphasia severity is modulated by race and lesion size in chronic survivors: A retrospective study.

Introduction: In stroke survivors with aphasia (SWA), differences in behavioral language performance have been observed between Black and White Americans. These racial differences in aphasia outcomes may reflect biological stroke severity, disparities in access to care, potential assessment bias, or interactions between these factors and race. Understanding the origin of disparities in aphasia outcomes is critical to any efforts to promote health equity among SWA.

Language and developmental plasticity after perinatal stroke.

The mature human brain is lateralized for language, with the left hemisphere (LH) primarily responsible for sentence processing and the right hemisphere (RH) primarily responsible for processing suprasegmental aspects of language such as vocal emotion. However, it has long been hypothesized that in early life there is plasticity for language, allowing young children to acquire language in other cortical regions when LH areas are damaged. If true, what are the constraints on functional reorganization? Which areas of the brain can acquire language, and what happens to the functions these regions ordinarily perform? We address these questions by examining long-term outcomes in adolescents and young adults who, as infants, had a perinatal arterial ischemic stroke to the LH areas ordinarily subserving sentence processing.

The organization of individually mapped structural and functional semantic networks in aging adults.

Language function in the brain, once thought to be highly localized, is now appreciated as relying on a connected but distributed network. The semantic system is of particular interest in the language domain because of its hypothesized integration of information across multiple cortical regions. Previous work in healthy individuals has focused on group-level functional connectivity (FC) analyses of the semantic system, which may obscure interindividual differences driving variance in performance.

A Weak Shadow of Early Life Language Processing Persists in the Right Hemisphere of the Mature Brain.

Studies of language organization show a striking change in cerebral dominance for language over development: We begin life with a left hemisphere (LH) bias for language processing, which is weaker than that in adults and which can be overcome if there is a LH injury. Over development this LH bias becomes stronger and can no longer be reversed. Prior work has shown that this change results from a significant reduction in the magnitude of language activation in right hemisphere (RH) regions in adults compared to children.

Cingulate transcranial direct current stimulation in adults with HIV.

Background: Neuronal dysfunction plays an important role in the high prevalence of HIV-associated neurocognitive disorders (HAND) in people with HIV (PWH). Transcranial direct current stimulation (tDCS)-with its capability to improve neuronal function-may have the potential to serve as an alternative therapeutic approach for HAND. Brain imaging and neurobehavioral studies provide converging evidence that injury to the anterior cingulate cortex (ACC) is highly prevalent and contributes to HAND in PWH, suggesting that ACC may serve as a potential neuromodulation target for HAND.

Simulated Attack Reveals How Lesions Affect Network Properties in Poststroke Aphasia.

Aphasia is a prevalent cognitive syndrome caused by stroke. The rarity of premorbid imaging and heterogeneity of lesion obscures the links between the local effects of the lesion, global anatomic network organization, and aphasia symptoms. We applied a simulated attack approach in humans to examine the effects of 39 stroke lesions (16 females) on anatomic network topology by simulating their effects in a control sample of 36 healthy (15 females) brain networks.

Absence of Perilesional Neuroplastic Recruitment in Chronic Poststroke Aphasia.

Background And Objectives: A prominent theory proposes that neuroplastic recruitment of perilesional tissue supports aphasia recovery, especially when language-capable cortex is spared by smaller lesions. This theory has rarely been tested directly and findings have been inconclusive. We tested the perilesional plasticity hypothesis using 2 fMRI tasks in 2 groups of patients with previous aphasia diagnosis.

Transcranial Alternating Current Stimulation (tACS) as a Treatment for Insomnia.

We investigated the effects of transcranial alternating stimulation (tACS) in patients with insomnia. Nine patients with chronic insomnia underwent two in-laboratory polysomnography, 2 weeks apart, and were randomized to receive tACS either during the first or second study. The stimulation was applied simultaneously and bilaterally at F3/M1 and F4/M2 electrodes (0.

Plasticity of the language system in children and adults.

The language system is perhaps the most unique feature of the human brain's cognitive architecture. It has long been a quest of cognitive neuroscience to understand the neural components that contribute to the hierarchical pattern processing and advanced rule learning required for language. The most important goal of this research is to understand how language becomes impaired when these neural components malfunction or are lost to stroke, and ultimately how we might recover language abilities under these circumstances.

Structural disconnection of the posterior medial frontal cortex reduces speech error monitoring.

Optimal performance in any task relies on the ability to detect and correct errors. The anterior cingulate cortex and the broader posterior medial frontal cortex (pMFC) are active during error processing. However, it is unclear whether damage to the pMFC impairs error monitoring.