Author
Ashwani Jha
Other affiliations: Department of Biotechnology, University of Edinburgh, University of Oxford ...read more
Bio: Ashwani Jha is an academic researcher from UCL Institute of Neurology. The author has contributed to research in topics: Deep brain stimulation & Subthalamic nucleus. The author has an hindex of 20, co-authored 44 publications receiving 2367 citations. Previous affiliations of Ashwani Jha include Department of Biotechnology & University of Edinburgh.
Papers
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University Hospital Southampton NHS Foundation Trust1, University of Southampton2, University of Newcastle3, University of Liverpool4, National Institute for Health Research5, Walton Centre6, King's College London7, University of Utah8, UCL Institute of Neurology9, University of Cambridge10, University of Edinburgh11, Manchester Academic Health Science Centre12, University of Oxford13, University College London14, Royal Victoria Infirmary15
TL;DR: This is the first nationwide, cross-specialty surveillance study of acute neurological and psychiatric complications of COVID-19 and provides valuable and timely data that are urgently needed by clinicians, researchers, and funders.
990 citations
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TL;DR: A newly described, electrophysiological method is used to describe cortico-subthalamic networks in humans and it is suggested that these networks may be involved in attentional and executive, particularly motor planning, processes, respectively.
Abstract: Both phenotype and treatment response vary in patients with Parkinson’s disease. Anatomical and functional imaging studies suggest that individual symptoms may represent malfunction of different segregated networks running in parallel through the basal ganglia. In this study, we use a newly described, electrophysiological method to describe cortico-subthalamic networks in humans. We performed combined magnetoencephalographic and subthalamic local field potential recordings in thirteen patients with Parkinson’s disease at rest. Two spatially and spectrally separated networks were identified. A temporoparietal-brainstem network was coherent with the subthalamic nucleus in the alpha (7–13 Hz) band, whilst a predominantly frontal network was coherent in the beta (15–35 Hz) band. Dopaminergic medication modulated the resting beta network, by increasing beta coherence between the subthalamic region and prefrontal cortex. Subthalamic activity was predominantly led by activity in the cortex in both frequency bands. The cortical topography and frequencies involved in the alpha and beta networks suggest that these networks may be involved in attentional and executive, particularly motor planning, processes, respectively.
* Abbreviations
: DICS
: dynamic imaging of coherent sources
LFP
: local field potential
SPM
: statistical parametric mapping
STN-LFP
: subthalamic nucleus local field potential
UPDRS
: Unified Parkinson’s Disease Rating Scale
392 citations
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TL;DR: The findings demonstrate that novel cation-independent adhesion mechanisms may mediate platelet–monocyte binding, representing a new therapeutic target after vascular injury associated with myocardial infarction, and evidence for a significant P-selectin–independent molecular component to the platelet-monocyte conjugation observed in peripheral blood.
Abstract: Background— Present therapies for acute coronary syndromes aim toward limiting platelet–platelet adhesion and aggregation processes. However, platelet–leukocyte interactions may contribute importantly to disease progression in the arterial wall. Recent studies suggest that prevention of platelet–leukocyte binding via P-selectin glycoprotein ligand-1 (PSGL-1) may be beneficial in animal models of vascular injury. Methods and Results— P-selectin–PSGL-1 interactions were found to account for most platelet–monocyte binding observed in peripheral blood samples from healthy donors. However, a significant component of observed adhesion was calcium independent, involving neither PSGL-1 nor P-selectin. Platelet–monocyte interactions were examined in 52 patients admitted within 14 hours of symptom onset, with acute coronary syndromes defined as unstable angina (n=12) and acute myocardial infarction (n=13) or noncardiac chest pain (n=27). When compared with patients with noncardiac chest pain, significantly elevated...
344 citations
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TL;DR: In this paper, the effect of synchronous and sequential finger movements and of the dopamine prodrug levodopa on induced power in the contralateral primary motor cortex (M1) and subthalamic nucleus (STN) was examined.
Abstract: Functional neurosurgery has afforded the opportunity to assess interactions between populations of neurons in the human cerebral cortex and basal ganglia in patients with Parkinson9s disease (PD). Interactions occur over a wide range of frequencies, and the functional significance of those >30 Hz is particularly unclear. Do they improve movement, and, if so, in what way? We acquired simultaneously magnetoencephalography and direct recordings from the subthalamic nucleus (STN) in 17 PD patients. We examined the effect of synchronous and sequential finger movements and of the dopamine prodrug levodopa on induced power in the contralateral primary motor cortex (M1) and STN and on the coherence between the two structures. We observed discrete peaks in M1 and STN power at 60–90 Hz and at 300–400 Hz. All these power peaks increased with movement and levodopa treatment. Only STN activity at 60–90 Hz was coherent with activity in M1. Directionality analysis showed that STN gamma activity at 60–90 Hz tended to drive gamma activity in M1. The effects of levodopa on both local and distant synchronization at 60–90 Hz correlated with the degree of improvement in bradykinesia-rigidity as did local STN activity at 300–400 Hz. Despite this, there were no effects of movement type, nor interactions between movement type and levodopa in the STN, nor in the coherence between STN and M1. We conclude that synchronization at 60–90 Hz in the basal ganglia cortical network is prokinetic but likely through a modulatory effect rather than any involvement in explicit motor processing.
172 citations
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TL;DR: Phase–amplitude coupling between beta band and high-frequency oscillations correlates with severity of motor impairments and Parkinsonian pathophysiology is more closely linked with low-beta band frequencies.
146 citations
Cited by
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TL;DR: The timing of a sensory input relative to a gamma cycle determined the amplitude and precision of evoked responses and provided the first causal evidence that distinct network activity states can be induced in vivo by cell-type-specific activation.
Abstract: Corticalgammaoscillations(20280Hz)predictincreasesinfocusedattention,andfailureingammaregulationisahallmark of neurological and psychiatric disease. Current theory predicts that gamma oscillations are generated by synchronous activity of fast-spiking inhibitory interneurons, with the resulting rhythmic inhibition producing neural ensemble synchrony by generating a narrow window for effective excitation. We causally tested these hypotheses in barrel cortex in vivo by targeting optogenetic manipulation selectively to fast-spiking interneurons. Here we show that light-driven activation of fast-spiking interneurons atvariedfrequencies (82200Hz) selectivelyamplifies gamma oscillations. Incontrast, pyramidal neuron activation amplifies only lower frequency oscillations, a cell-type-specific double dissociation. We found that the timing of a sensory input relative to a gamma cycle determined the amplitude and precision of evoked responses. Our data directly support the fast-spiking-gamma hypothesis and provide the first causal evidence that distinct network activity states can be induced in vivo by cell-type-specific activation.
2,453 citations
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TL;DR: It is hypothesized that beta oscillations and/or coupling in the beta-band are expressed more strongly if the maintenance of the status quo is intended or predicted, than if a change is expected.
Abstract: In this review, we consider the potential functional role of beta-band oscillations, which at present is not yet well understood. We discuss evidence from recent studies on top-down mechanisms involved in cognitive processing, on the motor system and on the pathophysiology of movement disorders that suggest a unifying hypothesis: beta-band activity seems related to the maintenance of the current sensorimotor or cognitive state. We hypothesize that beta oscillations and/or coupling in the beta-band are expressed more strongly if the maintenance of the status quo is intended or predicted, than if a change is expected. Moreover, we suggest that pathological enhancement of beta-band activity is likely to result in an abnormal persistence of the status quo and a deterioration of flexible behavioural and cognitive control.
1,837 citations
01 Jan 2016
TL;DR: As you may know, people have search numerous times for their chosen novels like this statistical parametric mapping the analysis of functional brain images, but end up in malicious downloads.
Abstract: Thank you very much for reading statistical parametric mapping the analysis of functional brain images. As you may know, people have search numerous times for their chosen novels like this statistical parametric mapping the analysis of functional brain images, but end up in malicious downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they cope with some infectious bugs inside their desktop computer.
1,719 citations
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TL;DR: In this article, the authors provided robust estimates of incidence rates and relative risks of neurological and psychiatric diagnoses in patients in the 6 months following a COVID-19 diagnosis, using data obtained from the TriNetX electronic health records network (with over 81 million patients).
1,162 citations
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TL;DR: The patient who has a delayed recovery from an episode of covid-19 that was managed in the community or in a standard hospital ward is referred to, which can be divided into those who may have serious sequelae and those with a non-specific clinical picture, often dominated by fatigue and breathlessness.
Abstract: ### What you need to know
Post-acute covid-19 (“long covid”) seems to be a multisystem disease, sometimes occurring after a relatively mild acute illness.1 Clinical management requires a whole-patient perspective.2 This article, intended for primary care clinicians, relates to the patient who has a delayed recovery from an episode of covid-19 that was managed in the community or in a standard hospital ward. Broadly, such patients can be divided into those who may have serious sequelae (such as thromboembolic complications) and those with a non-specific clinical picture, often dominated by fatigue and breathlessness. The specialist rehabilitation needs of a third group, covid-19 patients whose acute illness required intensive care, have been covered elsewhere.3
In the absence of agreed definitions, for the purposes of this article we define post-acute covid-19 as extending beyond three weeks from the onset of first symptoms and chronic covid-19 as extending beyond 12 weeks. Since many people were not tested, and false negative tests are common,4 we suggest that a positive test for covid-19 is not a prerequisite for diagnosis.
### How common is it?
Around 10% of patients who have tested positive for SARS-CoV-2 virus remain unwell beyond three weeks, and a smaller proportion for months (see box 1).7 This is based on the UK COVID Symptom Study, in which people enter their ongoing symptoms on a smartphone app. This percentage is lower than that cited in many published observational …
1,045 citations