A5087252242- Neurobiology of Language and Bilingualism
- Spatial Neglect and Hemispheric Dysfunction
- Hemispheric Asymmetry in Neuroscience
- Advanced Neuroimaging Techniques and Applications
- Action Observation and Synchronization
- Neuroscience and Music Perception
- Vestibular and auditory disorders
- Dementia and Cognitive Impairment Research
- Stroke Rehabilitation and Recovery
- Functional Brain Connectivity Studies
- Neural dynamics and brain function
- Reading and Literacy Development
- Transcranial Magnetic Stimulation Studies
- Meningioma and schwannoma management
- Cerebrovascular and Carotid Artery Diseases
- Neurology and Historical Studies
- Cerebral Palsy and Movement Disorders
- Motor Control and Adaptation
- Epilepsy research and treatment
- Acute Ischemic Stroke Management
- Neural and Behavioral Psychology Studies
- Advanced Memory and Neural Computing
- EEG and Brain-Computer Interfaces
- Hearing Loss and Rehabilitation
Universidad del Desarrollo
2017-2024
University College London
2017-2023
University Memory and Aging Center
2023
University of California, San Francisco
2023
Wellcome Centre for Human Neuroimaging
2017-2023
Center for Neurosciences
2023
National Hospital for Neurology and Neurosurgery
2018-2022
University of Concepción
2019
Abstract Broca’s area in the posterior half of left inferior frontal gyrus has long been thought to be critical for speech production. The current view is that long-term production outcome patients with damage best explained by combination and neighbouring regions including underlying white matter, which was also damaged Paul two historic cases. Here, we dissociate effect from surrounding areas studying 134 stroke survivors relatively circumscribed lobe lesions spared lateral parietal...
This study investigated how sample size affects the reproducibility of findings from univariate voxel-based lesion-deficit analyses (e.g., lesion-symptom mapping and morphometry). Our effect interest was strength between brain damage speech articulation difficulties, as measured in terms proportion variance explained. First, we identified a region by searching on voxel-by-voxel basis for areas where greater lesion load associated with poorer using large 360 right-handed English-speaking...
Acquired language disorders after stroke are strongly associated with left hemisphere damage. When difficulties observed in the context of right strokes, patients usually considered to have atypical functional anatomy. By systematically integrating behavioural and lesion data from brain damaged MRI neurologically normal participants, we investigated when why strokes cause disorders. Experiment 1 studied right-handed unilateral that (n = 109) or 369) hemispheres. The most frequently impaired...
Abstract The non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA) is a neurodegenerative syndrome primarily defined by the presence apraxia speech (AoS) and/or expressive agrammatism. In addition, many patients exhibit dysarthria receptive This leads to substantial phenotypic variation within speech-language domain across individuals and time, in terms both specific combination symptoms as well their severity. How resolve such heterogeneity nfvPPA matter debate. ‘Splitting’...
In this study, we hypothesized that if the same deficit can be caused by damage to one or another part of a distributed neural system, then voxel-based analyses might miss critical lesion sites because preservation each site will not consistently associated with preserved function. The first our investigation used multiple regression data from 359 right-handed stroke survivors identify brain regions where load is picture naming abilities after factoring out variance related object...
Abstract The logopenic variant of primary progressive aphasia (lvPPA) is a neurodegenerative syndrome characterized linguistically by gradual loss repetition and naming skills resulting from left posterior temporal inferior parietal atrophy. Here, we sought to identify which specific cortical loci are initially targeted the disease (epicenters) investigate whether atrophy spreads through predetermined networks. First, used cross‐sectional structural MRI data individuals with lvPPA define...
Broca's area in the posterior half of left inferior frontal gyrus has traditionally been considered an important node speech production network. Nevertheless, recovery reported, to different degrees, within a few months damage area. Importantly, contemporary evidence suggests that, area, its part (i.e. pars opercularis) plays more prominent role than anterior triangularis). In this study, we therefore investigated brain activation patterns that underlie accurate following stroke opercular By...
Transcranial magnetic stimulation focused on either the left anterior supramarginal gyrus or opercular part of inferior frontal has been reported to transiently impair ability perform phonological more than semantic tasks. Here we tested whether processing abilities were also impaired following lesions these regions in right-handed, English speaking adults, who investigated at least 1 year after a left-hemisphere stroke. When our interest limited 0.5 cm3 grey matter centred around sites that...
Around a third of stroke survivors suffer from acquired language disorders (aphasia), but current medicine cannot predict whether or when they might recover. Prognostic research in this area increasingly draws on datasets associating structural brain imaging data with outcome scores for ever-larger samples patients. The aim is to learn brain-behaviour trends these data, and generalize those outcomes new practical significance work depends the expected breadth that generalization. Here, we...
Prior studies have reported inconsistency in the lesion sites associated with verbal short-term memory impairments. Here we asked: How many different can account for selective impairments that persist over time, and how consistently do these impair memory? We assessed using a forward digit span task from Comprehensive Aphasia Test. First, identified incidence of sample 816 stroke survivors (541 males/275 females; age at onset 56 ± 13 years; time post-stroke 4.4 5.2 years). Second, studied...
Controversy surrounds the interpretation of higher activation for pseudoword compared to word reading in left precentral gyrus and pars opercularis. Specifically, does these regions reflect: (1) demands on sublexical assembly articulatory codes, or (2) retrieval effort because combinations codes are unfamiliar? Using fMRI, 84 neurologically intact participants, we addressed this issue by comparing repetition words (W) pseudowords (P) naming objects (O) from pictures sounds. As do not provide...
Using fMRI, we investigated how right temporal lobe gliomas affecting the posterior superior sulcus alter neural processing observed during speech perception and production tasks. Behavioural language testing showed that three pre-operative neurosurgical patients with grade 2, 3 or 4 tumours had same pattern of mild impairment in domains object naming written word comprehension. When matching heard words for semantic relatedness (a task), these under-activation tumour infiltrated compared to...
Abstract Paradoxical lesions are secondary brain that ameliorate functional deficits caused by the initial insult. This effect has been explained in several ways; particularly reduction of inhibition, or increases excitatory-to-inhibitory synaptic balance within perilesional tissue. In this article, we simulate how and when a modification excitatory–inhibitory triggers reversal deficit primary lesion. For this, introduce in-silico to an active inference model auditory word repetition. The...
Establishing whether speech and language therapy after stroke has beneficial effects on speaking ability is challenging because of the need to control for multiple non-therapy factors known influence recovery. We investigated how at three time points post-stroke differed in patients who received varying amounts clinical first month post-stroke. In contrast prior studies, we factored out variance from: initial severity impairment, amount later therapy, left right hemisphere lesion size site....
Prior studies have shown that the left posterior superior temporal sulcus (pSTS) and temporo-parietal junction (TPJ) both contribute to phonological short-term memory, speech perception production. Here, by conducting a within-subjects multi-factorial fMRI study, we dissociate response profiles of these regions third region – anterior ascending terminal branch (atSTS), which lies dorsal pSTS ventral TPJ. First, show each was more activated (i) 1-back matching on visually presented verbal...
Prior research has revealed distinctive patterns of impaired language abilities across the three variants Primary Progressive Aphasia (PPA): nonfluent/agrammatic (nfvPPA), logopenic (lvPPA) and semantic (svPPA). However, little is known about whether, to what extent, non-verbal cognitive abilities, such as processing speed, are impacted in PPA patients. This because neuropsychological tests typically contain linguistic stimuli require spoken output, being therefore sensitive verbal deficits...
Abstract Both classic and contemporary models of auditory word repetition involve at least four left hemisphere regions: primary cortex for processing sounds; pSTS (within Wernicke’s area) images speech; pOp Broca’s motor overt speech articulation. Previous functional-MRI (fMRI) studies confirm that activates these regions, in addition to many others. Crucially, however, do not specify how regions interact drive each other during repetition. Here, we used dynamic causal modelling, test the...
Specific regions of the cerebellum are activated when neurologically intact adults speak, and cerebellar damage can impair speech production early after stroke, but how brain supports accurate years remains unknown. We investigated this in patients with lesions affecting that normally recruited during production. Functional MRI activation these patients, measured various single word tasks, was compared to controls, patient controls spared regions. Our analyses revealed that, a range had...
Background A greater amount of education is known to positively impact language skills in neurotypical populations, but its influence on outcomes and recovery after stroke remains unclear.
Abstract The logopenic variant of primary progressive aphasia (lvPPA) is a neurodegenerative syndrome characterized linguistically by gradual loss repetition and naming skills, resulting from left posterior temporal inferior parietal atrophy. Here, we sought to identify which specific cortical loci are initially targeted the disease (epicenters) investigate whether atrophy spreads through pre-determined networks. First, used cross-sectional structural MRI data individuals with lvPPA define...
Abstract Functional imaging studies of neurotypical adults report activation in the left putamen during speech production. The current study asked how stroke survivors with damage are able to produce correct spoken responses a range production tasks. Using functional magnetic resonance imaging, was assessed 5 patients circumscribed dorsal striatal lesions, 66 patient controls who did not have focal and 54 adults. As group, (our interest) showed higher than superior parietal cortex successful...
Abstract In the neurological model of language, repeating heard speech involves four left hemisphere regions: primary auditory cortex for processing sounds; Wernicke’s area images speech; Broca’s motor and overt articulation. Previous functional-MRI (fMRI) studies confirm that repetition activates these regions. Here, we used dynamic causal modelling (DCM) to test how regions interact with each other during single word pseudoword repetition. Contrary expectation, found that, both repetition,...