Tipu Z Aziz

Summary

Affiliation: University of Oxford
Country: UK

Publications

  1. doi request reprint Demand driven deep brain stimulation: regimes and autoregressive hidden Markov implementation
    John 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
  2. pmc Driving oscillatory activity in the human cortex enhances motor performance
    Raed 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
  3. doi request reprint Ventral periaqueductal grey stimulation alters heart rate variability in humans with chronic pain
    Erlick A C Pereira
    Nuffield Department of Surgery, University of Oxford, Oxford, UK
    Exp Neurol 223:574-81. 2010
  4. ncbi request reprint Physiological and harmonic components in neural and muscular coherence in Parkinsonian tremor
    Shouyan 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
  5. doi request reprint Persistent suppression of subthalamic beta-band activity during rhythmic finger tapping in Parkinson's disease
    Raed 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
  6. pmc A spatiotemporal analysis of gait freezing and the impact of pedunculopontine nucleus stimulation
    Wesley Thevathasan
    Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
    Brain 135:1446-54. 2012
  7. doi request reprint Oscillatory activity in the subthalamic nucleus during arm reaching in Parkinson's disease
    Raed A Joundi
    Functional Neurosurgery and Experimental Neurology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
    Exp Neurol 236:319-26. 2012
  8. doi request reprint Removing ECG noise from surface EMG signals using adaptive filtering
    Guohua Lu
    Department of Physiology, Anatomy and Genetics, University of Oxford, OX1 3PT, UK
    Neurosci Lett 462:14-9. 2009
  9. doi request reprint Sustained reduction of hypertension by deep brain stimulation
    Erlick A C Pereira
    Nuffield Department of Surgery, University of Oxford, Oxford, UK
    J Clin Neurosci 17:124-7. 2010
  10. doi request reprint High-frequency stimulation of the subthalamic nucleus selectively decreases central variance of rhythmic finger tapping in Parkinson's disease
    Raed A Joundi
    Functional Neurosurgery and Experimental Neurology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
    Neuropsychologia 50:2460-6. 2012

Detail Information

Publications53

  1. doi request reprint Demand driven deep brain stimulation: regimes and autoregressive hidden Markov implementation
    John 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...
  2. pmc Driving oscillatory activity in the human cortex enhances motor performance
    Raed 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
    ....
  3. doi request reprint Ventral periaqueductal grey stimulation alters heart rate variability in humans with chronic pain
    Erlick 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...
  4. ncbi request reprint Physiological and harmonic components in neural and muscular coherence in Parkinsonian tremor
    Shouyan 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
    ..To differentiate physiological from harmonic components in coherence analysis of the tremor-related neural and muscular signals by comparing power, cross-power and coherence spectra...
  5. doi request reprint Persistent suppression of subthalamic beta-band activity during rhythmic finger tapping in Parkinson's disease
    Raed 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...
  6. pmc A spatiotemporal analysis of gait freezing and the impact of pedunculopontine nucleus stimulation
    Wesley Thevathasan
    Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
    Brain 135:1446-54. 2012
    ..Bilateral stimulation was more effective than unilateral...
  7. doi request reprint Oscillatory activity in the subthalamic nucleus during arm reaching in Parkinson's disease
    Raed 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...
  8. doi request reprint Removing ECG noise from surface EMG signals using adaptive filtering
    Guohua 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...
  9. doi request reprint Sustained reduction of hypertension by deep brain stimulation
    Erlick 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...
  10. doi request reprint High-frequency stimulation of the subthalamic nucleus selectively decreases central variance of rhythmic finger tapping in Parkinson's disease
    Raed 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...
  11. doi request reprint Stimulation of the subthalamic nucleus improves velocity of ballistic movements in Parkinson's disease
    Raed 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
    ....
  12. ncbi request reprint Time-frequency analysis of transient neuromuscular events: dynamic changes in activity of the subthalamic nucleus and forearm muscles related to the intermittent resting tremor
    Shou 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...
  13. ncbi request reprint Connectivity of the human pedunculopontine nucleus region and diffusion tensor imaging in surgical targeting
    Kalai 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...
  14. doi request reprint The sensory and motor representation of synchronized oscillations in the globus pallidus in patients with primary dystonia
    Xuguang 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...
  15. doi request reprint The autonomic effects of deep brain stimulation--a therapeutic opportunity
    Jonathan 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
    ....
  16. doi request reprint Sing the mind electric - principles of deep brain stimulation
    Morten 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...
  17. doi request reprint Reduced limbic connections may contraindicate subgenual cingulate deep brain stimulation for intractable depression
    Jennifer 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...
  18. pmc A block to pre-prepared movement in gait freezing, relieved by pedunculopontine nucleus stimulation
    Wesley 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...
  19. doi request reprint Application of a null-beamformer to source localisation in MEG data of deep brain stimulation
    Hamid 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
    ....
  20. ncbi request reprint Translational principles of deep brain stimulation
    Morten 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...
  21. pmc Tremor suppression by rhythmic transcranial current stimulation
    John 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...
  22. doi request reprint Comparison of contralateral pallidotomy vs. pallidal stimulation after prior unilateral pallidotomy for Parkinson's disease
    Jonathan 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...
  23. doi request reprint Cortical and subcortical connections within the pedunculopontine nucleus of the primate Macaca mulatta determined using probabilistic diffusion tractography
    Bhooma R Aravamuthan
    Department of Physiology, University of Oxford, Parks Road, Oxford OX1 3PT, UK
    J Clin Neurosci 16:413-20. 2009
    ....
  24. ncbi request reprint Extracting burst and tonic components from surface electromyograms in dystonia using adaptive wavelet shrinkage
    Shou 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...
  25. doi request reprint Connectivity of the pedunculopontine nucleus in parkinsonian freezing of gait
    Patrick 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...
  26. doi request reprint Chronic pedunculopontine nucleus stimulation restores functional connectivity
    Patrick 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...
  27. doi request reprint The role of the subthalamic nucleus in response inhibition: evidence from local field potential recordings in the human subthalamic nucleus
    Nicola 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...
  28. pmc Diffusion imaging of whole, post-mortem human brains on a clinical MRI scanner
    Karla 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...
  29. doi request reprint On the origin of oscillopsia during pedunculopontine stimulation
    Ned Jenkinson
    Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
    Stereotact Funct Neurosurg 90:124-9. 2012
    ....
  30. doi request reprint Intra-operative deep brain stimulation of the periaqueductal grey matter modulates blood pressure and heart rate variability in humans
    Alexander 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...
  31. doi request reprint Depiction of the neuroscientific principles of human motion 2 millennia ago by Lucretius
    Jonathan 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...
  32. ncbi request reprint Deep brain stimulation for chronic pain investigated with magnetoencephalography
    Morten 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...
  33. doi request reprint Deep brain stimulation for cluster headache
    Patrick 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
    ....
  34. doi request reprint Human periventricular grey somatosensory evoked potentials suggest rostrocaudally inverted somatotopy
    Erlick A C Pereira
    Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
    Stereotact Funct Neurosurg 91:290-7. 2013
    ..Such knowledge may assist DBS target localisation for neuropathic pain syndromes related to particular body regions like brachial plexopathies, anaesthesia dolorosa and phantom limb pain. ..
  35. ncbi request reprint Deep brain stimulation can regulate arterial blood pressure in awake humans
    Alexander 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...
  36. ncbi request reprint Deep brain stimulation for the alleviation of post-stroke neuropathic pain
    Sarah 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...
  37. ncbi request reprint Involvement of the medial pallidum in focal myoclonic dystonia: A clinical and neurophysiological case study
    Xuguang 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...
  38. ncbi request reprint Reversal of akinesia in experimental parkinsonism by GABA antagonist microinjections in the pedunculopontine nucleus
    Dipankar 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...
  39. doi request reprint Anatomy, physiology, and pathophysiology of the pedunculopontine nucleus
    Ned 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...
  40. pmc A specific and rapid neural signature for parental instinct
    Morten 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...
  41. doi request reprint Identifying cardiovascular neurocircuitry involved in the exercise pressor reflex in humans using functional neurosurgery
    Shanika 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...
  42. ncbi request reprint Pedunculopontine nucleus electric stimulation alleviates akinesia independently of dopaminergic mechanisms
    Ned 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...
  43. pmc Identifying cardiorespiratory neurocircuitry involved in central command during exercise in humans
    Alexander L Green
    Department of Neurosurgery, Radcliffe Infirmary, Oxford OX2 6HE, UK
    J Physiol 578:605-12. 2007
    ....
  44. ncbi request reprint Controlling the heart via the brain: a potential new therapy for orthostatic hypotension
    Alexander 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...
  45. doi request reprint Dystonia: a surgeon's perspective
    Tipu 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...
  46. ncbi request reprint Stimulating the human midbrain to reveal the link between pain and blood pressure
    Alexander 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...
  47. doi request reprint The periaqueductal grey area and control of blood pressure in neurodegeneration
    Holly Sitsapesan
    Nuffield Department of Surgical Science, University of Oxford, Level 3, West Wing, Oxford, OX3 9DU, UK
    Clin Auton Res 23:215-9. 2013
    ..This may imply a functional involvement of the PAG/PVG in the neurodegenerative process. ..
  48. doi request reprint Switching off micturition using deep brain stimulation at midbrain sites
    Alexander 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...
  49. doi request reprint Optogenetics--shining light on neurosurgical conditions
    Victoria 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...
  50. doi request reprint Long-term outcomes of deep brain stimulation for neuropathic pain
    Sandra G J Boccard
    Department of Physiology, Anatomy and Genetics, University of Oxford, United Kingdom
    Neurosurgery 72:221-30; discussion 231. 2013
    ..Deep brain stimulation (DBS) to treat neuropathic pain refractory to pharmacotherapy has reported variable outcomes and has gained United Kingdom but not USA regulatory approval...
  51. ncbi request reprint Optimising coherence estimation to assess the functional correlation of tremor-related activity between the subthalamic nucleus and the forearm muscles
    Shou Yan Wang
    University Laboratory of Physiology, University of Oxford, UK
    J Neurosci Methods 136:197-205. 2004
    ....
  52. ncbi request reprint Deep brain stimulation of the pedunculopontine region in the normal non-human primate
    Dipankar 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...
  53. ncbi request reprint Connectivity of the human periventricular-periaqueductal gray region
    Emma Sillery
    Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Headington, United Kingdom
    J Neurosurg 103:1030-4. 2005
    ..The effects of DBS in this region are probably related to the release of endogenous endorphins, but until the connectivity of this region is better understood the mechanisms will remain unclear...