In JoVE (3)

Other Publications (14)

Articles by Alexandre F. DaSilva in JoVE

 JoVE Neuroscience

Electrode Positioning and Montage in Transcranial Direct Current Stimulation

1Headache & Orofacial Pain Effort (H.O.P.E.), Biologic & Material Sciences, School of Dentistry, University of Michigan, 2Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 3Charité, University Medicine Berlin, 4Department of Biomedical Engineering, The City College of New York

JoVE 2744

 JoVE Medicine

Technique and Considerations in the Use of 4x1 Ring High-definition Transcranial Direct Current Stimulation (HD-tDCS)

1Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 2School of Medicine, Pontifical Catholic University of Ecuador, 3Charité University Medicine Berlin, 4The City College of The City University of New York, 5Headache & Orofacial Pain Effort (H.O.P.E.), Biologic & Materials Sciences, School of Dentistry, University of Michigan

JoVE 50309

 JoVE Medicine

3D-Neuronavigation In Vivo Through a Patient's Brain During a Spontaneous Migraine Headache

1Headache & Orofacial Pain Effort (H.O.P.E.), Biological & Materials Sciences Department, University of Michigan School of Dentistry, 2Michigan Center for Oral Health Research (MCOHR), University of Michigan School of Dentistry, 3Translational Neuroimaging Laboratory, Molecular & Behavioral Neuroscience Institute, University of Michigan, 4PET Physics Section, Division of Nuclear Medicine, Radiology Department, University of Michigan, 53DLab, University of Michigan, 6Department of Obstetrics and Gynecology, University of Michigan

JoVE 50682

Other articles by Alexandre F. DaSilva on PubMed

Specific and Somatotopic Functional Magnetic Resonance Imaging Activation in the Trigeminal Ganglion by Brush and Noxious Heat

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience. Aug, 2003  |  Pubmed ID: 12944520

We used functional magnetic resonance imaging (fMRI) to assess activation in the trigeminal ganglion during innocuous mechanical (brush) and noxious thermal (46 degrees C) stimulation of the face within the receptive fields of each of the three divisions of the trigeminal nerve in healthy volunteers. For both stimulus types, we observed signal changes only in the ipsilateral ganglion, and activation occurred somatotopically, as predicted by the known anatomical segregation of the neurons comprising the ophthalmic (V1), maxillary (V2), and mandibular (V3) divisions of the nerve. Signal decreased after brush stimuli and increased after the application of noxious heat. The abilities to detect somatotopic activation within the ganglion and to segregate non-noxious mechanical from noxious thermal stimuli suggest that fMRI will be valuable for measuring changes in the trigeminal ganglion in human models of neuropathic pain and in the clinical condition itself and may also be useful in the evaluation of pain therapies.

The Temporomandibular Joint: Clinical and Surgical Aspects

Neuroimaging Clinics of North America. Aug, 2003  |  Pubmed ID: 14631691

Advances in imaging techniques have greatly enhanced the ability to visualize the internal anatomy of the temporomandibular joint and have increased understanding of the etiology of many temporomandibular disorders. When used together with careful history and physical examination, this knowledge can contribute to better treatment outcomes.

A Primer on Diffusion Tensor Imaging of Anatomical Substructures

Neurosurgical Focus. Jul, 2003  |  Pubmed ID: 15355006

In this article, the authors review the application of diffusion tensor (DT) magnetic resonance (MR) imaging to demonstrate anatomical substructures that cannot be resolved by conventional structural imaging. They review the physical basis of DT imaging and provide illustrative anatomical examples. The DT imaging technique measures the self-diffusion, or random thermal motion, of the endogenous water in nerve tissue. Because of the preferred diffusion of water molecules along the nerve fiber direction, DT imaging can measure the orientation of the neural fiber structure within each voxel of the MR image. The fiber orientation information yielded by DT imaging provides a new contrast mechanism that can be used to resolve images of anatomical substructures that cannot otherwise be visualized using conventional structural imaging. The authors illustrate how DT imaging can resolve individual pathways in the brainstem as well as individual nuclei of the thalamus and conclude by describing potential applications in neurosurgery.

Anatomical Alterations of the Visual Motion Processing Network in Migraine with and Without Aura

PLoS Medicine. Oct, 2006  |  Pubmed ID: 17048979

Patients suffering from migraine with aura (MWA) and migraine without aura (MWoA) show abnormalities in visual motion perception during and between attacks. Whether this represents the consequences of structural changes in motion-processing networks in migraineurs is unknown. Moreover, the diagnosis of migraine relies on patient's history, and finding differences in the brain of migraineurs might help to contribute to basic research aimed at better understanding the pathophysiology of migraine.

Cluster Headache: a Review of Neuroimaging Findings

Current Pain and Headache Reports. Apr, 2007  |  Pubmed ID: 17367592

Classified as a trigeminal autonomic cephalalgia, cluster headache is characterized by recurrent short-lived excruciating pain attacks, which are concurrent with autonomic signs. These clinical features have led to the assumption that cluster headache's pathophysiology involves central nervous system structures, including the hypothalamus. In the past decade, neuroimaging studies have confirmed such clinically derived theory by uncovering in vivo neuronal changes located in the inferior posterior hypothalamus. Using a variety of neuro-imaging techniques (functional , biochemical , and structural ) in patients with cluster headache, we are making improvements in our understanding of the role of the brain in this disorder. This article summarizes neuroimaging findings in cluster headache patients, describing neuronal changes that occur during attacks and remission, as well as during hypothalamic stimulation.

Interictal Alterations of the Trigeminal Somatosensory Pathway and Periaqueductal Gray Matter in Migraine

Neuroreport. Mar, 2007  |  Pubmed ID: 17435592

Migraine has been traditionally considered a nonprogressive, paroxysmal disorder with no brain abnormalities between attacks. We used diffusion tensor imaging to examine interictal diffusion properties of the brains of migraineurs with aura, migraineurs without aura and matched healthy controls. Areas of lower fractional anisotropy were present in migraineurs along the thalamocortical tract. In addition, migraineurs with aura had lower fractional anisotropy in the ventral trigeminothalamic tract, and migraineurs without aura had lower fractional anisotropy in the ventrolateral periaqueductal grey matter. Our results indicate the presence of permanent interictal changes in migraineurs, pointing to an effect of migraine on the trigeminal somatosensory and modulatory pain systems.

Thickening in the Somatosensory Cortex of Patients with Migraine

Neurology. Nov, 2007  |  Pubmed ID: 18025393

To examine morphologic changes in the somatosensory cortex (SSC) of patients with migraine.

Colocalized Structural and Functional Changes in the Cortex of Patients with Trigeminal Neuropathic Pain

PloS One. 2008  |  Pubmed ID: 18923647

Recent data suggests that in chronic pain there are changes in gray matter consistent with decreased brain volume, indicating that the disease process may produce morphological changes in the brains of those affected. However, no study has evaluated cortical thickness in relation to specific functional changes in evoked pain. In this study we sought to investigate structural (gray matter thickness) and functional (blood oxygenation dependent level - BOLD) changes in cortical regions of precisely matched patients with chronic trigeminal neuropathic pain (TNP) affecting the right maxillary (V2) division of the trigeminal nerve. The model has a number of advantages including the evaluation of specific changes that can be mapped to known somatotopic anatomy.

One-year RTMS Treatment for Refractory Trigeminal Neuralgia

Journal of Pain and Symptom Management. Oct, 2009  |  Pubmed ID: 19713068

TDCS-induced Analgesia and Electrical Fields in Pain-related Neural Networks in Chronic Migraine

Headache. Sep, 2012  |  Pubmed ID: 22512348

We investigated in a sham-controlled trial the analgesic effects of a 4-week treatment of transcranial direct current stimulation (tDCS) over the primary motor cortex in chronic migraine. In addition, using a high-resolution tDCS computational model, we analyzed the current flow (electric field) through brain regions associated with pain perception and modulation.

Reduced Basal Ganglia μ-opioid Receptor Availability in Trigeminal Neuropathic Pain: a Pilot Study

Molecular Pain. 2012  |  Pubmed ID: 23006894

Although neuroimaging techniques have provided insights into the function of brain regions involved in Trigeminal Neuropathic Pain (TNP) in humans, there is little understanding of the molecular mechanisms affected during the course of this disorder. Understanding these processes is crucial to determine the systems involved in the development and persistence of TNP.

Immediate Effects of TDCS on the μ-opioid System of a Chronic Pain Patient

Frontiers in Psychiatry / Frontiers Research Foundation. 2012  |  Pubmed ID: 23130002

We developed a unique protocol where transcranial direct current stimulation (tDCS) of the motor cortex is performed during positron emission tomography (PET) scan using a μ-opioid receptor (μOR) selective radiotracer, [(11)C]carfentanil. This is one of the most important central neuromechanisms associated with pain perception and regulation. We measured μOR non-displaceable binding potential (μOR BP(ND)) in a trigeminal neuropathic pain patient (TNP) without creating artifacts, or posing risks to the patient (e.g., monitoring of resistance). The active session directly improved in 36.2% the threshold for experimental cold pain in the trigeminal allodynic area, mandibular branch, but not the TNP patient's clinical pain. Interestingly, the single active tDCS application considerably decreased μORBP(ND) levels in (sub)cortical pain-matrix structures compared to sham tDCS, especially in the posterior thalamus. Suggesting that the μ-opioidergic effects of a single tDCS session are subclinical at immediate level, and repetitive sessions are necessary to revert ingrained neuroplastic changes related to the chronic pain. To our knowledge, we provide data for the first time in vivo that there is possibly an instant increase of endogenous μ-opioid release during acute motor cortex neuromodulation with tDCS.

Real-time Sharing and Expression of Migraine Headache Suffering on Twitter: a Cross-sectional Infodemiology Study

Journal of Medical Internet Research. 2014  |  Pubmed ID: 24698747

Although population studies have greatly improved our understanding of migraine, they have relied on retrospective self-reports that are subject to memory error and experimenter-induced bias. Furthermore, these studies also lack specifics from the actual time that attacks were occurring, and how patients express and share their ongoing suffering.

Migraine and the Mu-Opioidergic System-Can We Directly Modulate It? Evidence from Neuroimaging Studies

Current Pain and Headache Reports. Jul, 2014  |  Pubmed ID: 24842566

Migraine is a chronic trigeminal pain condition that affects the daily lives of a large part of our population. Its debilitating headache attacks, with increased sensitivity to multiple forms of stimuli, force many patients to rely on over the counter analgesics and resort to abuse of prescription medications, particularly opioid agonists. In the latter case, the indiscriminate medication-driven activation of the opioid system can lead to undesired side effects, such as the augmentation of hyperalgesia and allodynia, as well as the chronification of the attacks. However, we still lack information regarding the impact of migraine attacks and their relief on the function of μ-opioid receptor (μOR) mediated neurotransmission, the primary target of opioid medications. This line of inquiry is of particular importance as this neurotransmitter system is arguably the brain's most important endogenous mechanism involved in pain regulation, and understanding this endogenous mechanism is crucial in determining the effectiveness of opioid medications. Recently, new advances in molecular neuroimaging and neuromodulation have provided important information that can elucidate, in vivo, the role of the endogenous opioid system in migraine suffering and relief.

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