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Our publication database contains 7436 publications dating back to 1943. You can browse some of the most recently added entries below, or you can:

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Recently Added Publications


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Hierarchical representation of multi-step tasks in multiple-demand and default mode networks
Authors:
WEN, T., DUNCAN, J.D., MITCHELL, D.
Reference:
The Journal of Neuroscience
Year of publication:
-
CBU number:
8541
Abstract:
Task episodes consist of sequences of steps that are performed to achieve a goal. We used fMRI to examine neural representation of task identity, component items, and sequential position, focusing on two major cortical systems – the multiple-demand (MD) and default mode networks (DMN). Human participants (20 male, 22 female) learned six tasks each consisting of four steps. Inside the scanner, participants were cued which task to perform and then sequentially identified the target item of each step in the correct order. Univariate time-course analyses indicated that intra-episode progress was tracked by a tonically increasing global response, plus an increasing phasic step response specific to MD regions. Inter-episode boundaries evoked a widespread response at episode onset, plus a marked offset response specific to DMN regions. Representational similarity analysis was used to examine representation of task identity and component steps. Both networks represented the content and position of individual steps, however the DMN preferentially represented task identity while the MD network preferentially represented step-level information. Thus, although both MD and DMN networks are sensitive to step-level and episode-level information in the context of hierarchical task performance, they exhibit dissociable profiles in terms of both temporal dynamics and representational content. The results suggest collaboration of multiple brain regions in control of multi-step behavior, with MD regions particularly involved in processing the detail of individual steps, and DMN adding representation of broad task context.
Data available, click to request
The Neurodevelopmental Spectrum of Synaptic Vesicle Cycling Disorders
Authors:
ABINAYAH, J., NG-CORDELL, E., HANNA, N., BRKIC, D., BAKER, K.
Reference:
Journal of Neuroschemistry
Year of publication:
In Press
CBU number:
8540
Abstract:
In this review, we describe and discuss neurodevelopmental phenotypes arising from rare, high penetrance genomic variants which directly influence synaptic vesicle cycling (SVC disorders). Pathogenic variants in each SVC disorder gene lead to disturbance of at least one SVC sub-process, namely vesicle trafficking (for example KIF1A and GDI1), clustering (for example TRIO, NRXN1 and SYN1), docking and priming (for example STXBP1), fusion (for example SYT1 and PRRT2) or re-uptake (for example DNM1, AP1S2 and TBC1D24). We observe that SVC disorders share a common set of neurological symptoms (movement disorders, epilepsies), cognitive impairments (developmental delay, intellectual disabilities, cerebral visual impairment) and mental health difficulties (autism, ADHD, psychiatric symptoms). On the other hand, there is notable phenotypic variation between and within disorders, which may reflect selective disruption to SVC sub-processes, spatiotemporal and cell-specific gene expression profiles, mutation-specific effects, or modifying factors. Understanding the common cellular and systems mechanisms underlying neurodevelopmental phenotypes in SVC disorders, and the factors responsible for variation in clinical presentations and outcomes, may translate to personalised clinical management and improved quality of life for patients and families.
The effect of phantom stimulation and pseudomonophasic pulse shapes on pitch perception by cochlear implant listeners
Authors:
LAMPING, W., DEEKS, J.M., Marozeau, J., CARLYON, R.P.
Reference:
Journal of the Association for Research in Otolaryngology
Year of publication:
In Press
CBU number:
8539
Cortico-cortical and thalamocortical changes in functional connectivity and white matter structural integrity after reward-guided learning of visuospatial discriminations in rhesus monkeys
Authors:
Mitchell, A., Pekekanos, V., Premereur, E., MITCHELL, D., Mason, S., Chakraborty, S., Lee, A.
Reference:
The Journal of Neuroscience
Year of publication:
In Press
CBU number:
8538
Abstract:
The frontal cortex and temporal lobes together regulate complex learning and memory capabilities. Here, we collected resting-state functional and diffusion-weighted magnetic resonance imaging data before and after male rhesus macaque monkeys received extensive training to learn novel visuospatial discriminations (reward-guided learning). We found functional connectivity changes in orbitofrontal, ventromedial prefrontal, inferotemporal, entorhinal, retrosplenial, and anterior cingulate cortices, the subicular complex and the dorsal, medial thalamus. These cortico-cortical and thalamocortical changes in functional connectivity were accompanied by related white matter structural alterations in the uncinate fasciculus, fornix, and ventral prefrontal tract – tracts that connect (sub)cortical networks and are implicated in learning and memory processes in monkeys and humans. After the well-trained monkeys received fornix transection, they were impaired in learning new visuospatial discriminations. In addition, the functional connectivity profile that was observed after the training was altered. These changes were accompanied by white matter changes in the ventral prefrontal tract although the integrity of the uncinate fasciculus remained unchanged. Our experiments highlight the importance of different communication relayed amongst cortico-cortical and thalamocortical circuitry for the ability to learn new visuospatial associations (learning-to-learn) and to make reward-guided decisions.
Integrated intelligence from distributed brain activity
Authors:
DUNCAN, J., ASSEM, M., SHASHIDHARA, S.
Reference:
Trends in Cognitive Sciences
Year of publication:
In Press
CBU number:
8537
Abstract:
How does organized cognition arise from distributed brain activity? Recent analyses of fluid intelligence suggest a core process of cognitive focus and integration, organizing the components of a cognitive operation into the required computational structure. A cortical “multiple-demand” (MD) system is closely linked to fluid intelligence, and recent imaging data define nine specific MD patches distributed across frontal, parietal and occipitotemporal cortex. Wide cortical distribution, relative functional specialization and strong connectivity suggest a basis for cognitive integration, matching electrophysiological evidence for binding of cognitive operations to their contents. Though still only in broad outline, these data suggest how distributed brain activity can build complex, organized cognition.
Brain-to-Brain Coupling in the Gamma-Band as a Marker of Shared Intentionality
Authors:
Barraza, P., PEREZ, A., and Rodriguez, E.
Reference:
Frontiers in Human Neuroscience, 30 July 2020
Year of publication:
2020
CBU number:
8536
Abstract:
Cooperation and competition are two ways of social interaction keys to life in society. Recent EEG-based hyperscanning studies reveal that cooperative and competitive interactions induce an increase in interbrain coupling. However, whether this interbrain coupling effect is just a reflection of inter-subject motor coordination or can also signal the type of social interaction is unknown. Here, we show that behavioral coordination and social interaction type can be distinguished according to the frequency of oscillation in which the brains are coupled. We use EEG to simultaneously measure the brain activity of pairs of subjects, while they were performing a visual cue-target task in a cooperative and competitive manner. Behavioral responses were quasi-simultaneous between subject pairs for both competitive and cooperative conditions, with faster average response times for the competitive condition. Concerning brain activity, we found increased interbrain coupling in theta band (3–7 Hz) during cooperation and competition, with stronger coupling during competitive interactions. This increase of interbrain theta coupling correlated with a decrease in reaction times of the dyads. Interestingly, we also found an increase in brain-to-brain coupling in gamma band (38– 42 Hz) only during cooperative interactions. Unlike the theta coupling effect, the gamma interbrain coupling did not correlate with dyads’ reaction times. Taken together, these results suggest that theta interbrain coupling could be linked to motor coordination processes common to cooperative and competitive interactions, while gamma brain-tobrain coupling emerges as an electrophysiological marker of shared intentionality during cooperative interactions.
URL:
Activity in the Fronto-Parietal Multiple-Demand Network is Robustly Associated with Individual Differences in Working Memory and Fluid Intelligence
Authors:
ASSEM, M., Asher Blank, I., Mineroff, Z. Ademoglu,A., Fedorenko, E.
Reference:
Cortex
Year of publication:
In Press
CBU number:
8535
Abstract:
Numerous brain lesion and fMRI studies have linked individual differences in executive abilities and fluid intelligence to brain regions of the fronto-parietal “multiple-demand” (MD) network. Yet, fMRI studies have yielded conflicting evidence as to whether better executive abilities are associated with stronger or weaker MD activations and whether this relationship is restricted to the MD network. Here, in a large-sample (n=216) fMRI investigation, we found that stronger activity in MD regions – functionally defined in individual participants – was robustly associated with more accurate and faster responses on a spatial working memory task performed in the scanner, as well as fluid intelligence measured independently (n=114). In line with some prior claims about a relationship between language and fluid intelligence, we also found a weak association between activity in the brain regions of the left fronto-temporal language network during an independent passive reading task, and performance on the working memory task. However, controlling for the level of MD activity abolished this relationship, whereas the MD activity-behavior association remained highly reliable after controlling for the level of activity in the language network. Finally, we demonstrate how unreliable MD activity measures, coupled with small sample sizes, could falsely lead to the opposite, negative, association that has been reported in some prior studies. Taken together, these results demonstrate that a core component of individual differences variance in executive abilities and fluid intelligence is selectively and robustly positively associated with the level of activity in the MD network, a result that aligns well with lesion studies.
URL:
Data available, click to request
Multi-dimensional connectivity: a conceptual and mathematical review.
Authors:
Basti, A., Nili, H., HAUK, O., Marzetti, L., HENSON, R.N.
Reference:
NeuroImage, 1 November 2020, 117140
Year of publication:
2020
CBU number:
8534
Abstract:
The estimation of functional connectivity between regions of the brain, for example based on statistical dependencies between the time series of activity in each region, has become increasingly important in neuroimaging. Typically, multiple time series (e.g. from each voxel in fMRI data) are first reduced to a single time series that summarises the activity in a region of interest, e.g. by averaging across voxels or by taking the first principal component; an approach we call one-dimensional connectivity. However, this summary approach ignores potential multi-dimensional connectivity between two regions, and a number of recent methods have been proposed to capture such complex dependencies. Here we review the most common multi-dimensional connectivity methods, from an intuitive perspective, from a formal (mathematical) point of view, and through a number of simulated and real (fMRI and MEG) data examples that illustrate the strengths and weaknesses of each method. The paper is accompanied with both functions and scripts, which implement each method and reproduce all the examples.
URL:
Data available, click to request
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.
URL:
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.
URL:


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