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Our publication database contains 7428 publications dating back to 1943. You can browse some of the most recently added entries below, or you can:

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Synaptic loss in primary tauopathies revealed by [11C]UCB-J positron emission tomography
Authors:
Holland,N., Jones, S., Savulich, G., Wiggins, J.K., Hong, Y.T., Fryer, T.D., Manayaki, R., Milicevic Sephton, S., Boros, I., Malpetti, M., HEZEMANS, F.H., Aigbirhio, F.I., Coles, J.P., O’Brien, J., ROWE, J.B.
Reference:
Movement Disorders
Year of publication:
In Press
CBU number:
8533
Abstract:
Background: Synaptic loss is a prominent and early feature of many neurodegenerative diseases. Objectives: We tested the hypothesis that synaptic density is reduced in the primary tauopathies of progressive supranuclear palsy (PSP-Richardson’s syndrome) and amyloid–negative corticobasal syndrome (CBS). Methods: Forty four participants (15 CBS, 14 PSP, and 15 age-/sex-/education-matched controls) underwent positron emission tomography (PET) with the radioligand [11C]UCB-J, which binds to synaptic vesicle glycoprotein 2A (SV2A), a marker of synaptic density; participants also had 3T magnetic resonance imaging and clinical and neuropsychological assessment. Results: Nine CBS patients had negative amyloid biomarkers determined by [11C]PiB PET and hence were deemed likely to have corticobasal degeneration (CBD). Patients with PSP-Richardson’s syndrome and amyloid-negative CBS were impaired in executive, memory and visuospatial tasks. [11C]UCB-J binding was reduced across frontal, temporal, parietal, and occipital lobes, cingulate, hippocampus, insula, amygdala and subcortical structures in both PSP and CBD patients compared to controls (p<0.01), with median reductions up to 50%, consistent with post mortem data. Reductions of 20-30% were widespread even in the areas of the brain with minimal atrophy. There was a negative correlation between global [11C]UCB-J binding and the PSP and CBD rating scales (R= -0.61 p<0.002, R= -0.72 p<0.001, respectively) and a positive correlation with the revised Addenbrookes Cognitive Examination (R=0.52, p=0.01). Conclusions: We confirm severe synaptic loss in PSP and CBD in proportion to disease severity, providing critical insight into the pathophysiology of primary degenerative tauopathies. [11C]UCB-J may facilitate treatment strategies for disease-modification, synaptic maintenance or restoration.
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The effect of non-communicative eye movements on joint attention
Authors:
Caruana, N., Alhasan, A., Wagner, K, Kaplan, D.M., WOOLGAR, A., & McArthur, G.
Reference:
Quarterly Journal of Experimental Psychology
Year of publication:
In Press
CBU number:
8532
Abstract:
Eye movements provide important signals for joint attention. However, those eye movements that indicate bids for joint attention often occur amongst non-communicative eye movements. The current study investigated the influence of these non-communicative eye movements on subsequent joint attention responsivity. Participants played an interactive game with an avatar which required both players to search for a visual target on a screen. The player who discovered the target used their eyes to initiate joint attention. We compared participants’ saccadic reaction times (SRTs) to the avatar’s joint attention bids when they were preceded by non-communicative eye movements that predicted the location of the target (Predictive Search), did not predict the location of the target (Random Search), and when there were no non-communicative eye gaze movements prior to joint attention (No Search). We also included a control condition in which participants completed the same task, but responded to a dynamic arrow stimulus instead of the avatar’s eye movements. For both eye and arrow conditions, participants had slower SRTs in Random Search trials than No Search and Predictive Search trials. However, these effects were smaller for eyes than for arrows. These data suggest that joint attention responsivity for eyes is relatively stable to the presence and predictability of spatial information conveyed by non-communicative gaze. Contrastingly, random sequences of dynamic arrows had a much more disruptive impact on subsequent responsivity compared to predictive arrow sequences. This may reflect specialised social mechanisms and expertise for selectively responding to communicative eye gaze cues during dynamic interactions, which is likely facilitated by the integration of ostensive eye contact cues.
Functional brain alterations following mild-to-moderate sensorineural hearing loss in children
Authors:
Calcus, A., Tuomainen, O., Campos, A., Rosen, S. & HALLIDAY, L.F.
Reference:
Elife, 01 Oct 2019, 8
Year of publication:
2019
CBU number:
8531
Abstract:
Auditory deprivation in the form of deafness during development leads to lasting changes in central auditory system function. However, less is known about the effects of mild-to-moderate sensorineural hearing loss (MMHL) during development. Here, we used a longitudinal design to examine late auditory evoked responses and mismatch responses to nonspeech and speech sounds for children with MMHL. At Time 1, younger children with MMHL (8-12 years; n = 23) showed age-appropriate mismatch negativities (MMNs) to sounds, but older children (12-16 years; n = 23) did not. Six years later, we re-tested a subset of the younger (now older) children with MMHL (n = 13). Children who had shown significant MMNs at Time 1 showed MMNs that were reduced and, for nonspeech, absent at Time 2. Our findings demonstrate that even a mild-to-moderate hearing loss during early-to-mid childhood can lead to changes in the neural processing of sounds in late childhood/adolescence. Data can be found at: https://github.com/acalcus/MMHL.git
URL:
The verbal, nonverbal and structural bases of functional communication abilities in aphasia
Authors:
Schumacher, R., Bruehl, S., HALAI, A., LAMBON RALPH, M.A
Reference:
Brain Communications
Year of publication:
In Press
CBU number:
8530
Abstract:
The ability to communicate, functionally, after stroke or other types of acquired brain injury is crucial for the person involved and the people around them. Accordingly, assessment of functional communication is increasingly used in large-scale randomized controlled trials as the primary outcome measure. Despite the importance of functional communication abilities to everyday life and their centrality to the measured efficacy of aphasia interventions, there is little knowledge about how commonly-used measures of functional communication relate to each other, whether they capture and grade the full range of patients’ remaining communication skills and how these abilities relate to the patients’ verbal and nonverbal impairments as well as the underpinning lesions. Going beyond language-only factors is essential given that nonverbal abilities can play a crucial role in an individual’s ability to communicate effectively. The current study, based on a large sample of patients covering the full range and types of poststroke aphasia, addressed these important, open questions. The investigation combined data from three established measures of functional communication (ANELT, Scenario Test, COAST) with a thorough assessment of verbal and nonverbal cognition as well as structural neuroimaging. The key findings included: (a) due to floor or ceiling effects, the full range of patients’ functional communication abilities was not captured by a single assessment alone, limiting the utility of adopting individual tests as outcome measures in randomized controlled trials; (b) phonological abilities were most strongly related to all measures of functional communication; and (c) nonverbal cognition was particularly crucial when language production was relatively impaired and other modes of communication were allowed, when patients rated their own communication abilities, and when carers rated patients’ basic communication abilities. Finally, in addition to lesion load being significantly related to all measures of functional communication, lesion analyses showed partially overlapping clusters in language regions for the functional communication tests. Moreover, mirroring the findings from the regression analyses, additional regions previously associated with nonverbal cognition emerged for the Scenario Test and for the Patient COAST. In conclusion, our findings elucidated the cognitive and neural bases of functional communication abilities, which may inform future clinical practice regarding assessments and therapy. In particular, it is necessary to use more than one measure to capture the full range and multifaceted nature of patients’ functional communication abilities and a therapeutic focus on nonverbal cognition might have positive effects on this important aspect of activity and participation.
A tutorial and tool for exploring feature similarity gradients with MRI data
Authors:
Bajada, C.J., Costa Campos, L.Q., Caspers, S., Muscat, R., Parker, G.J.M., LAMBON RALPH, M.A., Cloutman, L.L., Trujillo-Barreto, N.J.,
Reference:
NeuroImage
Year of publication:
In Press
CBU number:
8529
Abstract:
There has been an increasing interest in examining organisational principles of the cerebral cortex (and subcortical regions) using different MRI features such as structural or functional connectivity. Despite the widespread interest, introductory tutorials on the underlying technique targeted for the novice neuroimager are sparse in the literature. Articles that investigate various “neural gradients” (for example based on region studied “cortical gradients,” “cerebellar gradients,” “hippocampal gradients” etc … or feature of interest “functional gradients,” “cytoarchitectural gradients,” “myeloarchitectural gradients” etc…) have increased in popularity. Thus, we believe that it is opportune to discuss what is generally meant by “gradient analysis”. We introduce basics concepts in graph theory, such as graphs themselves, the degree matrix, and the adjacency matrix. We discuss how one can think about gradients of feature similarity (the similarity between timeseries in fMRI, or streamline in tractography) using graph theory and we extend this to explore such gradients across the whole MRI scale; from the voxel level to the whole brain level. We proceed to introduce a measure for quantifying the level of similarity in regions of interest. We propose the term “the Vogt-Bailey index” for such quantification to pay homage to our history as a brain mapping community. We run through the techniques on sample datasets including a brain MRI as an example of the application of the techniques on real data and we provide several appendices that expand upon details. To maximise intuition, the appendices contain a didactic example describing how one could use these techniques to solve a particularly pernicious problem that one may encounter at a wedding. Accompanying the article is a tool, available in both MATLAB and Python, that enables readers to perform the analysis described in this article on their own data. We refer readers to the graphical abstract as an overview of the analysis pipeline presented in this work.
The relationship between executive functions and fluid intelligence in multiple sclerosis
Authors:
Goitia, B., Bruno, D., Abrevaya, S., Sedeno, L., Ibanez, A., Manes, F., Sigman, M., Sinay, V., Torralva, T., DUNCAN, J., Roca, M.
Reference:
PLoS ONE, 15(4), E0231868
Year of publication:
2020
CBU number:
8528
Abstract:
Background & objective Deficits in cognitive functions dependent upon the integrity of the prefrontal cortex have been described in Multiple Sclerosis (MS). In a series of studies we have shown that fluid intelligence (g) is a substantial contributor to frontal deficits and that, for some classical “executive” tasks, frontal deficits were entirely explained by g. However, for another group of frontal tasks deficits remained once g was introduced as a covariate. This second set of tests included multitasking and theory of mind tasks. In the present study, we aimed at determining the role of fluid intelligence in frontal deficits seen in patients with MS. Methods A group of patients with Relapsing Remitting MS (n = 36) and a group of control subjects (n = 42) were assessed with a battery of classical executive tests (which included the Wiscon- sin Card Sorting Test, Verbal Fluency, and Trail Making Test B), a multitasking test, a theory of mind test and a fluid intelligence test. Results MS patients showed significant deficits in the fluid intelligence task. We found differences between patients and control subjects in all tests except for the multitasking test. The differ- ences in the classical executive tests became non-significant once fluid intelligence was introduced as a covariate, but differences in theory of mind remained. Conclusions The present results suggest that fluid intelligence can be affected in MS and that this impairment can play a role in the executive deficits described in MS.
URL:
Unconstrained multivariate EEG decoding can help detect lexical-semantic processing in individual children
Authors:
Petit, S., Badcock, N., Groostwagers, T., WOOLGAR, A.
Reference:
Nature Scientific Reports
Year of publication:
In Press
CBU number:
8527
Abstract:
In conditions such as minimally-verbal autism, standard assessments of language comprehension are often unreliable. Given the known heterogeneity within the autistic population, it is crucial to design tests of semantic comprehension that are sensitive in individuals. Recent efforts to develop neural signals of language comprehension have focused on the N400, a robust marker of lexical-semantic violation at the group level. However, homogeneity of response in individual neurotypical children has not been established. Here, we presented 20 neurotypical children with congruent and incongruent visual animations and spoken sentences while measuring their neural response using EEG. Despite robust group-level responses, we found high inter-individual variability in response to lexico-semantic anomalies. To overcome this, we analysed our data using temporally and spatially unconstrained MVPA, supplemented by descriptive analyses to examine the timecourse, topography, and strength of the effect. Our results show that neurotypical children exhibit heterogenous responses to lexical-semantic violation, implying that any application to heterogenous disorders such as ASD will require individual-subject analyses that are robust to variation in topology and timecourse of neural responses.
URL:
Graded, multi dimensional intragroup and intergroup variations in primary progressive aphasia and post stroke aphasia
Authors:
Ingram, R.U., HALAI, A.D., Pobric, G., PATTERSON, K., LAMBON RALPH, M.A.
Reference:
Brain
Year of publication:
In Press
CBU number:
8526
Abstract:
Language impairments caused by stroke (post-stroke aphasia) and neurodegeneration (primary progressive aphasia) have overlapping symptomatology, nomenclature and are classically divided into categorical subtypes. Surprisingly, primary progressive aphasia (PPA) and post-stroke aphasia (PSA) have rarely been directly compared in detail. Rather, previous studies have compared certain subtypes (e.g., semantic variants) or have focussed on a specific cognitive/linguistic task (e.g., reading). This study assessed a large range of linguistic and cognitive tasks across the full spectra of PSA and PPA. We applied varimax-rotated principal component analysis to explore the underlying structure of the variance in the assessment scores. Similar phonological, semantic and fluency-related components were found for PSA and PPA. A combined principal component analysis across the two aetiologies revealed graded intragroup and intergroup variations on all four extracted components. Classification analysis was employed to test, formally, whether there were any categorical boundaries for any subtypes of PPA or PSA. Semantic dementia formed a true diagnostic category (i.e., within group homogeneity and distinct between group differences), whereas there was considerable overlap and graded variations within and between other subtypes of PPA and PSA. These results suggest that (a) a multi-dimensional rather than categorical classification system may be a better conceptualisation of aphasia from both causes, and (b) despite the very different types of pathology, these broad classes of aphasia have considerable features in common.
URL:
The functional convergence and heterogeneity of social, episodic, and self-referential thought in the default mode network
Authors:
WEN, T., MITCHELL, D.J., DUNCAN, J.
Reference:
Cerebral Cortex
Year of publication:
2020
CBU number:
8525
Abstract:
The default mode network (DMN) is engaged in a variety of cognitive settings, including social, semantic, temporal, spatial, and self-related tasks. Andrews-Hanna et al. (2010, 2012) proposed that the DMN consists of three distinct functional-anatomical subsystems – a dorsal medial prefrontal cortex (dMPFC) subsystem that supports social cognition; a medial temporal lobe (MTL) subsystem that contributes to memory-based scene construction; and a set of midline core hubs that are especially involved in processing self-referential information. We examined activity in the DMN subsystems during six different tasks: (1) theory of mind, (2) moral dilemmas, (3) autobiographical memory, (4) spatial navigation, (5) self/other adjective judgement, and (6) a rest condition. At a broad level, we observed similar whole-brain activity maps for the six contrasts, and some response to every contrast in each of the three subsystems. In more detail, both univariate analysis and multivariate activity patterns showed partial functional separation, especially between dMPFC and MTL subsystems, though with less support for common activity across the midline core. Integrating social, spatial, self-related, and other aspects of a cognitive situation or episode, multiple components of the DMN may work closely together to provide the broad context for current mental activity.
URL:
Data available, click to request
Finding Hidden Treasures: A Child-Friendly Neural Test of Task-Following in Individuals Using Functional Transcranial Doppler Ultrasound
Authors:
Petit, S., Badcock, N., WOOLGAR, A.
Reference:
Neuropsychologia, 03 Jun 2020, :107515
Year of publication:
2020
CBU number:
8524
Abstract:
Despite growing interest in the mental life of individuals who cannot communicate verbally, objective and non-invasive tests of covert cognition are still sparse. In this study, we assessed the ability of neurotypical children to understand and follow task instructions by measuring neural responses through functional transcranial Doppler ultrasound (fTCD). We recorded blood flow velocity for the two brain hemispheres of twenty children (aged 9 to 12) while they performed either a language task or a visuospatial memory task, on identical visual stimuli. We extracted measures of neural lateralisation for the two tasks separately to investigate lateralisation, and we compared the left-minus-right pattern of activation across tasks to assess task-following. At the group level, we found that neural responses were left-lateralised when children performed the language task, and not when they performed the visuospatial task. However, with statistically robust analyses and controlled paradigms, significant lateralisation in individual children was less frequent than expected from the literature. Nonetheless, the pattern of hemispheric activation for the two tasks allowed us to confirm task-following in the group of participants, as well as in over half of the individuals. This provides a promising avenue for a covert and inexpensive test of children’s ability to covertly follow task instructions and perform different mental tasks on identical stimuli.
URL:


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