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ABSTRACT: Infant vocalisations are amongst the most biologically salient sounds in the environment and can draw the listener to the infant rapidly in both times of distress and joy. A region of the midbrain, the periaqueductal gray (PAG), has long been implicated in the control of urgent, survival-related behaviours. To test for PAG involvement in the processing of infant vocalisations, we recorded local field potentials (LFPs) from macroelectrodes implanted in this region in four adults who had undergone Deep Brain Stimulation. We found a significant difference occurring as early as 49ms from sound onset in activity recorded from the PAG in response to infant vocalisations compared to constructed control sounds and adult and animal affective vocalisations. This difference was not present in recordings from thalamic electrodes implanted in three of the patients. Time frequency analyses revealed distinct patterns of activity in the PAG for the three sound categories. These results suggest that human infant vocalisations can be discriminated from other emotional or acoustically similar sounds early in the auditory pathway. We propose that this specific, rapid activity in response to infant vocalisations may reflect the initiation of a state of heightened alertness necessary to instigate protective caregiving.
Social Cognitive and Affective Neuroscience 05/2013; · 6.13 Impact Factor
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ABSTRACT: In this study, a robust minimum variance beam-former (RMVB) is employed for source reconstruction in simultaneous MEG and local field potential (LFP) measurements. RMVB selects the electrical activity only from a specified volume of the brain while suppressing the rest. To improve imaging we added two more terms to the RMVB: the first term minimises the mean squared error (i.e. maximises the correlation) between the recorded LFP and reconstructed time courses from MEG data, the second term nulls the large inference induced by deep brain stimulation (DBS) device. A solution of this problem, relevant both with and without extra terms, is presented using the Lagrange multiplier method. This solution-if we ignore the new terms-has a simpler secular equation compared to its original solution and therefore is faster. The method is validated using both simulated and real data to show its potential use in practical applications.
Acoustics, Speech and Signal Processing (ICASSP), 2011 IEEE International Conference on; 06/2011 · 4.63 Impact Factor
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ABSTRACT: Deep brain stimulation is an increasingly prevalent surgical option in the treatment of a multitude of neurological conditions, most notably Parkinson's disease. The development of a neurofeedback device is driven primarily by stimulator habituation, surgical risk factors, the cost of battery replacement, and reported neuropsychiatric side-effects under prolonged chronic administration. Here we present two distinct regimes for stimulation delivery in chronic and acute symptomatic conditions, presented in the context of Parkinsonian bradykinesias and tremor. 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.
Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE; 10/2010
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H.R. Mohseni,
M.L. Kringelbach,
P.P. Smith,
A.L. Green,
C.E. Parsons,
K.S. Young,
J.-S. Brittain,
J.A. Hyam,
P.M. Schweder,
J.F. Stein, T.Z. Aziz
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ABSTRACT: In this paper, we present an analysis of magnetoencephalography (MEG) signals from a patient with whole-body chronic pain in order to investigate changes in neural activity induced by DBS. The patient is one of the few cases treated using DBS of the anterior cingulate cortex (ACC). Using MEG to reconstruct the neural activity of interest is challenging because of interference to the signal from the DBS device. We demonstrate that a null-beamformer can be used to localise neural activity despite artefacts caused by the presence of DBS electrodes and stimulus pulses. We subsequently verified the accuracy of our source localisation by correlating the predicted DBS electrode positions with their actual positions, previously identified using anatomical imaging. We also demonstrated increased activity in pain-related regions including the pre-supplementary motor area, brainstem periaqueductal gray and medial prefrontal areas when the patient was in pain compared to when the patient experienced pain relief.
Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE; 10/2010
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ABSTRACT: Following a total of 386 deep brain stimulation (DBS) procedures in Oxford, only two seizures have been recorded in the peri-operative period. Both patients had MS and underwent thalamic DBS for tremor and these 2 cases are presented here. The incidence of peri-operative seizures in MS patients undergoing DBS procedures is more than 8-fold greater than that expected for patients undergoing DBS procedures. Further experience with DBS procedures in MS patients is needed to determine whether there is a role for peri-operative anticonvulsants in these patients.
British Journal of Neurosurgery 06/2010; 24(3):289-90. · 0.88 Impact Factor
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ABSTRACT: Chronic abdominal pain is not uncommon and can be difficult to manage. We present the case of a 17-year-old man with a 4-year history of chronic abdominal pain. The patient had previously undergone abdominal surgery by way of laparoscopic appendicectomy and right nephrectomy for a mal-rotated kidney. The patient continued to suffer right-sided abdominal pain which was not controlled by analgesia. We report the successful implantation of a right D11 intercostal nerve stimulator to control the patient's pain. This is the first report of an implantable intercostal nerve stimulator to control intractable chronic abdominal pain.
Annals of The Royal College of Surgeons of England 04/2010; 92(3):W1-3. · 1.23 Impact Factor
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ABSTRACT: We describe dropped head syndrome in a patient with Parkinson's disease receiving subthalamic nucleus deep brain stimulation (DBS). Posterior occipitocervical instrumented fusion after transarticular screw fixation of an odontoid fracture is shown and its rationale explained. Pedunculopontine nucleus DBS as treatment for fall-predominant Parkinson's disease, and globus pallidus interna DBS for dystonia-predominant Parkinson's disease, are discussed.
Journal of Clinical Neuroscience 02/2010; 17(4):541-2. · 1.25 Impact Factor
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N J Ray,
N Jenkinson,
J Brittain,
P Holland,
C Joint,
D Nandi,
P G Bain,
N Yousif,
A Green,
J S Stein, T Z Aziz
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ABSTRACT: We measured reaction times during a stop-signal task while patients with Parkinson's disease were on and off unilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN). While reaction times to a "go" stimulus improved, there was no change in reaction times to the "stop" stimulus (SSRTs). However, changes in SSRTs induced by DBS were highly dependent on baseline SSRTs (measured off stimulation), with the greatest improvements being achieved by those with particularly slow reaction times. We therefore selected only those patients whose baseline SSRTs were within the limits of a control sample (N=10). In this group, SSRTs became slower when DBS was on. This finding suggests a role for the STN in response inhibition, which can be interrupted by DBS, observable only when more general improvements in Parkinson's function are minimised. We also compared the effects of unilateral left and right sided stimulation. We found a greater increase in SSRTs after DBS of the left STN.
Neuropsychologia 07/2009; 47(13):2828-34. · 3.64 Impact Factor
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British Journal of Neurosurgery 05/2009; 23(2):143-6. · 0.88 Impact Factor
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ABSTRACT: Cluster headache (CH) is a debilitating neurovascular condition characterized by severe unilateral periorbital head pain. Deep brain stimulation of the posterior hypothalamus has shown potential in alleviating CH in its most severe, chronic form. During surgical implantation of stimulating macroelectrodes for cluster head pain, one of our patients suffered a CH attack. During the attack local field potentials displayed a significant increase in power of approximately 20 Hz. To the authors' knowledge, this is the first recorded account of neuronal activity observed during a cluster attack. Our results both support and extend the current literature, which has long implicated hypothalamic activation as key to CH generation, predominantly through indirect haemodynamic neuroimaging techniques. Our findings reveal a potential locus in CH neurogenesis and a potential rationale for efficacious stimulator titration.
Cephalalgia 05/2009; 29(11):1165-73. · 3.43 Impact Factor
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Neurology 03/2009; 72(6):569-71. · 8.31 Impact Factor
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British Journal of Neurosurgery 01/2009; 22(6):814-5. · 0.88 Impact Factor
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ABSTRACT: The authors describe a novel approach to stereotactic biopsy of lesions of the lateral pons and medial cerebellar peduncle, and its diagnostic success without morbidity. A contralateral approach laterally expands the accessible infratentorial area. It may also confer a theoretical reduction in neurological deficit with passage through non-dominant right hemisphere.
British Journal of Neurosurgery 09/2008; 22(4):599-601. · 0.88 Impact Factor
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ABSTRACT: This study aimed to examine, using diffusion tensor imaging (DTI), differences in electrode placement in four patients undergoing deep brain stimulation for chronic neuropathic pain of varying aetiology. A pre-operative DTI was obtained for each patient, who was then implanted with deep brain stimulation electrodes in the periventricular/periaqueductal grey area with good pain relief. Using seeds from the postoperative MRI scan, probabilistic tractography was performed from the pre-operative DTI.
Journal of Clinical Neuroscience 08/2008; 15(7):801-5. · 1.25 Impact Factor
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Experimental Neurology 06/2008; 212(2):247-50. · 4.70 Impact Factor
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British Journal of Neurosurgery 05/2008; 22(2):298. · 0.88 Impact Factor
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ABSTRACT: Deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) has recently been shown to effectively ameliorate medically intractable axial symptoms of Parkinson's disease (PD). The effects of DBS are not limited to the targeted structure, but will affect the distributed anatomical networks to which the target structure belongs. Therefore, understanding the anatomical connections of the PPN will help elucidate treatment effects. Furthermore, establishing the topography of cortical and sub-cortical connections of the PPN in the human brain could aid accurate targeting of critical pathways in DBS. This article summarizes the connections of the PPN and the distribution of these connections within this nucleus (topography) as previously determined using diffusion tensor imaging (DTI) in healthy human volunteers and in a primate Macaca mulatta brain. These findings highlight DTI as a useful tool for surgical targeting for DBS of the PPN, and also show that DTI can be used to accurately probe the anatomy of the human and monkey brain in vivo.
British Journal of Neurosurgery 02/2008; 22 Suppl 1:S25-32. · 0.88 Impact Factor
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ABSTRACT: Deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) is a novel neurosurgical therapy developed to address symptoms of gait freezing and postural instability in Parkinson's disease and related disorders. Here, we summarize our non-human primate and neuroimaging research of relevance to our surgical targeting of the PPN. We also describe our clinical experience of PPN DBS with greatest motor improvements achieved by stimulation at low frequencies.
British Journal of Neurosurgery 02/2008; 22 Suppl 1:S41-4. · 0.88 Impact Factor
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ABSTRACT: This study aimed to find out whether preoperative diffusion tensor imaging (DTI) and probabilistic tractography could help with surgical planning for deep brain stimulation in the periaqueductal/periventricular grey area (PAG/PVG) in a patient with lower leg stump pain. A preoperative DTI was obtained from the patient, who then received DBS surgery in the PAG/PVG area with good pain relief. The postoperative MRI scan showing electrode placement was used to calculate four seed areas to represent the contacts on the Medtronic 3387 electrode. Probabilistic tractography was then performed from the pre-operative DTI image. Tracts were seen to connect to many areas within the pain network from the four different contacts. These initial findings suggest that preoperative DTI scanning and probabilistic tractography may be able to assist surgical planning in the future.
British Journal of Neurosurgery 11/2007; 21(5):485-90. · 0.88 Impact Factor
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ABSTRACT: The purpose of this study was to look at the connectivity of the posterior inferior hypothalamus in a patient implanted with a deep brain stimulating electrode using probabilistic tractography in conjunction with postoperative MRI scans. In a patient with chronic cluster headache we implanted a deep brain stimulating electrode into the ipsilateral postero-medial hypothalamus to successfully control his pain. To explore the connectivity, we used the surgical target from the postoperative MRI scan as a seed for probabilistic tractography, which was then linked to diffusion weighted imaging data acquired in a group of healthy control subjects. We found highly consistent connections with the reticular nucleus and cerebellum. In some subjects, connections were also seen with the parietal cortices, and the inferior medial frontal gyrus. Our results illustrate important anatomical connections that may explain the functional changes associated with cluster headaches and elucidate possible mechanisms responsible for triggering attacks.
Journal of Clinical Neuroscience 11/2007; 14(10):955-60. · 1.25 Impact Factor
