Research Topics
| Tipu Z AzizSummaryAffiliation: University of Oxford Country: UK Publications
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Detail Information
Publications
Demand driven deep brain stimulation: regimes and autoregressive hidden Markov implementationJohn Stuart Brittain
Centre of Excellence in Personalized Healthcare, Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Headington, OX3 7DQ, UK
Conf Proc IEEE Eng Med Biol Soc 2010:158-61. 2010..Implementation strategies are discussed with a focus on vector-autoregressive hidden Markov models for tremor prediction. Detection of simple motor actions versus tremor are compared in a preliminary performance analysis...
Driving oscillatory activity in the human cortex enhances motor performanceRaed A Joundi
Functional Neurosurgery and Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
Curr Biol 22:403-7. 2012....
Physiological and harmonic components in neural and muscular coherence in Parkinsonian tremorShouyan Wang
Department of Physiology, Anatomy, and Genetics, University of Oxford, and Department of Neurosurgery, Radcliffe Infirmary, Woodstock Road, Oxford OX2 6HE, UK
Clin Neurophysiol 117:1487-98. 2006..SIGNIFICANCE: The physiological or harmonic nature of a coherence peak at the double tremor frequency may be differentiated when the coherence spectra are compared with the power and in particular the cross-power spectra...- Ventral periaqueductal grey stimulation alters heart rate variability in humans with chronic painErlick A C Pereira
Nuffield Department of Surgery, University of Oxford, Oxford, UK
Exp Neurol 223:574-81. 2010..Heart rate variability (HRV) is an established measure of cardiovascular regulation, and an index of autonomic function... - A spatiotemporal analysis of gait freezing and the impact of pedunculopontine nucleus stimulationWesley Thevathasan
Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
Brain 135:1446-54. 2012..Bilateral stimulation was more effective than unilateral... - Oscillatory activity in the subthalamic nucleus during arm reaching in Parkinson's diseaseRaed A Joundi
Functional Neurosurgery and Experimental Neurology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
Exp Neurol 236:319-26. 2012..These findings point to functionally segregated roles for different oscillatory frequencies in motor preparation and performance... - Removing ECG noise from surface EMG signals using adaptive filteringGuohua Lu
Department of Physiology, Anatomy and Genetics, University of Oxford, OX1 3PT, UK
Neurosci Lett 462:14-9. 2009..This adaptive filter procedure proved a reliable and efficient tool to remove ECG artefact from surface EMGs with mixed and varied patterns of transient, short and long lasting dystonic contractions... - Sustained reduction of hypertension by deep brain stimulationErlick A C Pereira
Nuffield Department of Surgery, University of Oxford, Oxford, UK
J Clin Neurosci 17:124-7. 2010..6mm Hg and diastolic by 11.0mm Hg, alongside reductions in variability of heart rate and pulse pressure. This neurosurgical treatment may prove beneficial for medically refractory hypertension... - High-frequency stimulation of the subthalamic nucleus selectively decreases central variance of rhythmic finger tapping in Parkinson's diseaseRaed A Joundi
Functional Neurosurgery and Experimental Neurology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
Neuropsychologia 50:2460-6. 2012..Our experimental approach strongly implicates the STN, and more generally the basal ganglia, in the control of timing stability... - Stimulation of the subthalamic nucleus improves velocity of ballistic movements in Parkinson's diseaseRaed A Joundi
Functional Neurosurgery and Experimental Neurology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
Neuroreport 23:390-4. 2012.... - Connectivity of the human pedunculopontine nucleus region and diffusion tensor imaging in surgical targetingKalai A Muthusamy
Department of Physiology, Anatomy and Genetics, University of Oxford, UK
J Neurosurg 107:814-20. 2007..However, the anatomical connections of this region in humans are not known in any detail... - The sensory and motor representation of synchronized oscillations in the globus pallidus in patients with primary dystoniaXuguang Liu
Department of Physiology, Anatomy, and Genetics, University of Oxford, UK
Brain 131:1562-73. 2008..This study yields new insights into the pathophysiological mechanisms of primary dystonias and their treatment using pallidal deep brain stimulation... - Time-frequency analysis of transient neuromuscular events: dynamic changes in activity of the subthalamic nucleus and forearm muscles related to the intermittent resting tremorShou-Yan Wang
University Laboratory of Physiology, University of Oxford, Parks Road, Oxford OX1 3PT, UK
J Neurosci Methods 145:151-8. 2005..05). In comparison with short-time Fourier transform, similar results could be achieved using continuous wavelet transform of an appropriate wavelet with a higher temporal resolution but larger distortion in the high frequency... - The autonomic effects of deep brain stimulation--a therapeutic opportunityJonathan A Hyam
Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Department of Psychiatry, University of Oxford, Headley Way, Headington, Oxford OX3 9DU, UK
Nat Rev Neurol 8:391-400. 2012.... - A block to pre-prepared movement in gait freezing, relieved by pedunculopontine nucleus stimulationWesley Thevathasan
Department of Clinical Neurology, University of Oxford, UK
Brain 134:2085-95. 2011..These findings suggest a relative block to triggered, pre-prepared movement in gait freezing and postural instability, relieved by pedunculopontine nucleus stimulation... - Reduced limbic connections may contraindicate subgenual cingulate deep brain stimulation for intractable depressionJennifer A McNab
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Department of Clinical Neurology, University of Oxford, UK
J Neurosurg 111:780-4. 2009..Correspondence between preoperative and higher resolution ex vivo DT supports the validity of DT as a presurgical planning tool for DBS... - Translational principles of deep brain stimulationMorten L Kringelbach
University of Oxford, Department of Psychiatry, Warneford Hospital, Oxford, OX3 7JX, UK
Nat Rev Neurosci 8:623-35. 2007..The precise mechanisms of action for DBS remain uncertain, but here we give an up-to-date overview of the principles of DBS, its neural mechanisms and its potential future applications... - Application of a null-beamformer to source localisation in MEG data of deep brain stimulationHamid R Mohseni
Institute of Biomedical Engineering, School of Engineering Science, University of Oxford, UK
Conf Proc IEEE Eng Med Biol Soc 2010:4120-3. 2010.... - Sing the mind electric - principles of deep brain stimulationMorten L Kringelbach
University of Oxford, Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, UK
Eur J Neurosci 32:1070-9. 2010..At the same time, it is important to proceed with caution and not repeat the errors from the era of psychosurgery... - Comparison of contralateral pallidotomy vs. pallidal stimulation after prior unilateral pallidotomy for Parkinson's diseaseJonathan A Hyam
Department of Neurosurgery, John Radcliffe Hospital, University of Oxford, Oxford, UK
Neuromodulation 14:117-22; discussion 122. 2011..The aim of this study was to analyze which modality produced greater PD symptom improvement in patients with a prior pallidotomy and whether the chronological order of the pallidal surgery influenced the size of the improvement... - Cortical and subcortical connections within the pedunculopontine nucleus of the primate Macaca mulatta determined using probabilistic diffusion tractographyBhooma R Aravamuthan
Department of Physiology, University of Oxford, Parks Road, Oxford OX1 3PT, UK
J Clin Neurosci 16:413-20. 2009.... - Chronic pedunculopontine nucleus stimulation restores functional connectivityPatrick M Schweder
Departments of Neurosurgery, John Radcliffe Hospital, University of Oxford, Oxford, UK
Neuroreport 21:1065-8. 2010..This is the first reported case showing neuroimaging evidence of neuroplasticity after low-frequency DBS... - Extracting burst and tonic components from surface electromyograms in dystonia using adaptive wavelet shrinkageShou-Yan Wang
University Laboratory of Physiology, University of Oxford, Oxford, UK
J Neurosci Methods 139:177-84. 2004..We conclude that adaptive soft-thresholding wavelet shrinkage provides effective separation of burst and tonic activity in the compound EMG in dystonia. This separation should improve our understanding of the pathophysiology of dystonia... - Connectivity of the pedunculopontine nucleus in parkinsonian freezing of gaitPatrick M Schweder
Departments of Neurosurgery, John Radcliffe Hospital, University of Oxford, Oxford, UK
Neuroreport 21:914-6. 2010..The findings suggest that corticopontine projections, which cross at the pons are increased in gait freezing, highlighting the importance and role of corticopontine-cerebellar pathways in the pathophysiology of this phenomenon... - The role of the subthalamic nucleus in response inhibition: evidence from local field potential recordings in the human subthalamic nucleusNicola J Ray
Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
Neuroimage 60:271-8. 2012..This unexpected finding might suggest that gamma activity supports a go-process that not only responds to go-signals, but is also sensitive to stimuli that signal stopping... - Diffusion imaging of whole, post-mortem human brains on a clinical MRI scannerKarla L Miller
FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
Neuroimage 57:167-81. 2011..Despite these alterations, diffusion tractography of several major tracts is successfully demonstrated at both resolutions. We also report novel findings of cortical anisotropy and partial volume effects... - Persistent suppression of subthalamic beta-band activity during rhythmic finger tapping in Parkinson's diseaseRaed A Joundi
Functional Neurosurgery and Experimental Neurology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
Clin Neurophysiol 124:565-73. 2013..Here we sought support for the hypothesis that beta activity has a global function within the basal ganglia and is not directly involved in the coding of specific biomechanical parameters of movement... - On the origin of oscillopsia during pedunculopontine stimulationNed Jenkinson
Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
Stereotact Funct Neurosurg 90:124-9. 2012.... - Intra-operative deep brain stimulation of the periaqueductal grey matter modulates blood pressure and heart rate variability in humansAlexander L Green
Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK and Department of Anaesthesia, John Radcliffe Hospital, Oxford, UK
Neuromodulation 13:174-81. 2010..Understanding of the mechanisms by which this therapy causes cardiovascular modulation will inform future innovation in this field with the aim of improving the efficacy and safety of patient treatment options... - Deep brain stimulation for cluster headachePatrick J Grover
Nuffield Department of Surgery, University of Oxford and Oxford Functional Neurosurgery, Department of Neurological Surgery, The West Wing, John Radcliffe Hospital, Headley Way, Headington, Oxford, OX3 9DU, UK
J Clin Neurosci 16:861-6. 2009.... - Deep brain stimulation for chronic pain investigated with magnetoencephalographyMorten L Kringelbach
Department of Physiology, Anatomy and Genetics, University of Oxford, and Nuffield Department of Surgery, John Radcliffe Hospital, Oxford, UK
Neuroreport 18:223-8. 2007..Hence, they could potentially serve as future surgical targets to relieve chronic pain... - Depiction of the neuroscientific principles of human motion 2 millennia ago by LucretiusJonathan A Hyam
Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
Neurology 77:1000-4. 2011..Lucretius was the first commentator to introduce into Epicurean poetry the concept of such a mechanism consisting of a logical order of processes which are still consistent with modern concepts... - Deep brain stimulation for the alleviation of post-stroke neuropathic painSarah L F Owen
University Laboratory of Physiology, University of Oxford, UK
Pain 120:202-6. 2006..VAS scores show a mean improvement of 48.8% (SD 8.6%). However, there is a wide variation between patients. This study demonstrates that it is an effective treatment in 70% of such patients... - Deep brain stimulation can regulate arterial blood pressure in awake humansAlexander L Green
Department of Neurosurgery, Radcliffe Infirmary, University of Oxford, Oxford, UK
Neuroreport 16:1741-5. 2005..05). These changes were accompanied by analogous changes in diastolic blood pressure, pulse pressure, maximum dP/dt but not in the time interval between each R wave on the electrocardiogram... - Involvement of the medial pallidum in focal myoclonic dystonia: A clinical and neurophysiological case studyXuguang Liu
University Laboratory of Physiology, Parks Road, Oxford, United Kingdom
Mov Disord 17:346-53. 2002..High-frequency DBS may suppress the myoclonus by desynchronising abnormal pallidal oscillations. This case study has significant clinical implications, because at present, there is no effective treatment for focal myoclonic dystonia... - Identifying cardiovascular neurocircuitry involved in the exercise pressor reflex in humans using functional neurosurgeryShanika D Basnayake
Dept of Physiology, Anatomy and Genetics, Univ of Oxford, Oxford OX1 3PT, UK
J Appl Physiol 110:881-91. 2011..No significant changes were seen in the activity of other nuclei during occlusion. These electrophysiological data provide direct evidence for a role of the PAG in the integrating neurocircuitry of the exercise pressor reflex in humans... - Reversal of akinesia in experimental parkinsonism by GABA antagonist microinjections in the pedunculopontine nucleusDipankar Nandi
University Laboratory of Physiology, Oxford University, UK
Brain 125:2418-30. 2002..The effect of bicuculline microinjection in the PPN matches that of oral administration of L-dopa. This finding opens up new possibilities in the management of akinesia, the most intractable symptom of advanced Parkinson's disease... - Pedunculopontine nucleus electric stimulation alleviates akinesia independently of dopaminergic mechanismsNed Jenkinson
University Laboratory of Physiology, Oxford University, Oxford, UK
Neuroreport 17:639-41. 2006..This additivity suggests that pedunculopontine nucleus stimulation may improve movement by acting at a site downstream from where levodopa therapy affects the basal ganglia... - Controlling the heart via the brain: a potential new therapy for orthostatic hypotensionAlexander L Green
Department of Neurosurgery, Radcliffe Infirmary, Oxford, England
Neurosurgery 58:1176-83; discussion 1176-83. 2006..Our aim was to assess whether orthostatic hypotension can be successfully treated with deep brain stimulation of the periventricular/periaqueductal gray areas in humans... - Stimulating the human midbrain to reveal the link between pain and blood pressureAlexander L Green
Department of Neurosurgery, Radcliffe Infirmary, Woodstock Road, Oxford, OX2 6HE, United Kingdom
Pain 124:349-59. 2006..Thus stimulation of the PAG may partly control pain by reducing sympathetic activity as predicted by William James over a century ago... - Identifying cardiorespiratory neurocircuitry involved in central command during exercise in humansAlexander L Green
Department of Neurosurgery, Radcliffe Infirmary, Oxford OX2 6HE, UK
J Physiol 578:605-12. 2007.... - A specific and rapid neural signature for parental instinctMorten L Kringelbach
Department of Psychiatry, University of Oxford, Oxford, United Kingdom
PLoS ONE 3:e1664. 2008..This has potentially important clinical applications in relation to postnatal depression, and could provide opportunities for early identification of families at risk... - Dystonia: a surgeon's perspectiveTipu Z Aziz
Department of Neurosurgery, The John Radcliffe Hospital, Oxford, UK
Parkinsonism Relat Disord 15:S75-80. 2009..Some of the rarer types of dystonia that have also been treated with DBS are also described... - Anatomy, physiology, and pathophysiology of the pedunculopontine nucleusNed Jenkinson
Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, United Kingdom
Mov Disord 24:319-28. 2009..In accordance with this view, direct stimulation of the nucleus can ameliorate some symptoms of the disease, as demonstrated in both experimental animals and man... - Tremor suppression by rhythmic transcranial current stimulationJohn Stuart Brittain
Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
Curr Biol 23:436-40. 2013..With this technique we can achieve almost 50% average reduction in resting tremor amplitude and in so doing form the basis of a closed-loop tremor-suppression therapy that could be extended to other oscillopathies... - Switching off micturition using deep brain stimulation at midbrain sitesAlexander L Green
Nuffield Department of Surgical Science, University of Oxford, UK
Ann Neurol 72:144-7. 2012..Manipulation of neural continence pathways by deep brain stimulation may offer new avenues for the treatment of urinary incontinence of central origin... - Optogenetics--shining light on neurosurgical conditionsVictoria A Nowak
Department of Neurological Surgery, The John Radcliffe Hospital, Nuffield Department of Surgery, University of Oxford, Oxford, UK
Br J Neurosurg 24:618-24. 2010..The authors describe what optogenetics is and how it works, explain its significance to neurosurgery and illustrate its relevance by giving examples of recent translational and future clinical applications... - Optimising coherence estimation to assess the functional correlation of tremor-related activity between the subthalamic nucleus and the forearm musclesShou-Yan Wang
University Laboratory of Physiology, University of Oxford, UK
J Neurosci Methods 136:197-205. 2004.... - Deep brain stimulation of the pedunculopontine region in the normal non-human primateDipankar Nandi
University Laboratory of Physiology, University of Oxford, Parks Road, OX1 3PT, UK
J Clin Neurosci 9:170-4. 2002..At low frequencies (5-30 Hz), stimulation induced a 5-Hz tremor in the right arm.We conclude that stimulating the PPN region at high frequency causes akinesia, whereas low frequencies induce some positive motor effects... - Connectivity of the human periventricular-periaqueductal gray regionEmma Sillery
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Headington, United Kingdom
J Neurosurg 103:1030-4. 2005..CONCLUSIONS: These findings suggest that the PVG-PAG region may modulate pain by two mechanisms: one involving the antinociceptive system in the spinal cord and the other involving influences on the central pain network...