Neurology Commons^™

Treatment Of Gravitational Pulling Sensation In Patients With Mal De Debarquement Syndrome (Mdds): A Model-Based Approach, Sergei B. Yakushin, Theodore Raphan, Catherine Cho

Publications and Research

Perception of the spatial vertical is important for maintaining and stabilizing vertical posture during body motion. The velocity storage pathway of vestibulo-ocular reflex (VOR), which integrates vestibular, optokinetic, and proprioception in the vestibular nuclei vestibular-only (VO) neurons, has spatio-temporal properties that are defined by eigenvalues and eigenvectors of its system matrix. The yaw, pitch and roll eigenvectors are normally aligned with the spatial vertical and corresponding head axes. Misalignment of the roll eigenvector with the head axes was hypothesized to be an important contributor to the oscillating vertigo during MdDS. Based on this, a treatment protocol was developed using simultaneous …

Transcranial Direct Current Stimulation On Parkinson’S Disease: Systematic Review And Meta-Analysis, Paloma Cristina Alves De Oliveira, Thiago Anderson Brito De Araújo, Daniel Gomes Da Silva Machado, Abner Cardoso Rodrigues, Marom Bikson, Suellen Marinho Andrade, Alexandre Hideki Okano, Hougelle Simplicio, Rodrigo Pegado, Edgard Morya

Publications and Research

Background: Clinical impact of transcranial direct current stimulation (tDCS) alone for Parkinson’s disease (PD) is still a challenge. Thus, there is a need to synthesize available results, analyze methodologically and statistically, and provide evidence to guide tDCS in PD.

Objective: Investigate isolated tDCS effect in different brain areas and number of stimulated targets on PD motor symptoms.

Methods: A systematic review was carried out up to February 2021, in databases: Cochrane Library, EMBASE, PubMed/MEDLINE, Scopus, and Web of science. Full text articles evaluating effect of active tDCS (anodic or cathodic) vs. sham or control on motor symptoms of PD were …

Stimulating The Facial Nerve To Treat Ischemic Stroke: A Systematic Review, Turner S. Baker, Justin Robeny, Danna Cruz, Alexis Bruhat, Alfred-Marc Iloreta, Anthony Costa, Thomas James Oxley

Publications and Research

Acute ischemic stroke (AIS) is a common devastating disease that has increased yearly in absolute number of cases since 1990. While mechanical thrombectomy and tissue plasminogen activator (tPA) have proven to be effective treatments, their window-of-efficacy time is very short, leaving many patients with no viable treatment option. Over recent years there has been a growing interest in stimulating the facial nerves or ganglions to treat AIS. Pre-clinical studies have consistently demonstrated an increase in collateral blood flow (CBF) following ganglion stimulation, with positive indications in infarct size and neurological scores. Extensive human trials have focused on trans-oral electrical stimulation …

Leveraging High-Resolution 7-Tesla Mri To Derive Quantitative Metrics For The Trigeminal Nerve And Subnuclei Of Limbic Structures In Trigeminal Neuralgia, Judy Alper, Alan C. Seifert, Gaurav Verma, Kuang-Han Huang, Yael Jacob, Ameen Al Qadi, John W. Rutland, Sheetal Patel, Joshua Bederson, Raj K. Shrivastava, Bradley N. Delman, Priti Balchandani

Publications and Research

Background: Trigeminal Neuralgia (TN) is a chronic neurological disease that is strongly associated with neurovascular compression (NVC) of the trigeminal nerve near its root entry zone. The trigeminal nerve at the site of NVC has been extensively studied but limbic structures that are potentially involved in TN have not been adequately characterized. Specifically, the hippocampus is a stress-sensitive region which may be structurally impacted by chronic TN pain. As the center of the emotion-related network, the amygdala is closely related to stress regulation and may be associated with TN pain as well. The thalamus, which is involved in the trigeminal …

A Systematic Review And Meta-Analysis On The Efficacy Of Repeated Transcranial Direct Current Stimulation For Migraine, Guoshuai Cai, Zhu Xia, Leigh Charvet, Feifei Xiao, Abhishek Datta, X Michelle Androulakis

Publications and Research

Purpose: Transcranial direct current stimulation (tDCS) may have therapeutic potential in the management of migraine. However, studies to date have yielded conflicting results. We reviewed studies using repeated tDCS for longer than 4 weeks in migraine treatment, and performed meta-analysis on the efficacy of tDCS in migraine.

Methods: In this meta-analysis, we included the common outcome measurements reported across randomized controlled trials (RCTs). Subgroup analysis was performed at different post-treatment endpoints, and with different stimulation intensities and polarities.

Results: Five RCTs were included in the quantitative meta-analysis with a total of 104 migraine patients. We found a significant reduction of …

Network-Level Mechanisms Underlying Effects Of Transcranial Direct Current Stimulation (Tdcs) On Visuomotor Learning, Pejman Sehatpour, Clément Dondé, Matthew J. Hoptman, Johanna Kreither, Devin Adair, Elisa Dias, Blair Vail, Stephanie Rohrig, Gail Silipo, Javier Lopez-Calderon, Antigona Martinez, Daniel C. Javitt

Publications and Research

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation approach in which low level currents are administered over the scalp to influence underlying brain function. Prevailing theories of tDCS focus on modulation of excitation-inhibition balance at the local stimulation location. However, network level effects are reported as well, and appear to depend upon differential underlying mechanisms. Here, we evaluated potential network-level effects of tDCS during the Serial Reaction Time Task (SRTT) using convergent EEG- and fMRI-based connectivity approaches. Motor learning manifested as a significant (p <.0001) shift from slow to fast responses and corresponded to a significant increase in beta-coherence (p <.0001) and fMRI connectivity (p <.01) particularly within the visual-motor pathway. Differential patterns of tDCS effect were observed within different parametric task versions, consistent with network models. Overall, these findings demonstrate objective physiological effects of tDCS at the network level that result in effective behavioral modulation when tDCS parameters are matched to network-level requirements of the underlying task.

Applications Of Non-Invasive Neuromodulation For The Management Of Disorders Related To Covid-19, Abrahão Fontes Baptista, Adriana Baltar, Alexandre Hideki Okano, Alexandre Moreira, Ana Carolina Pinheiro Campos, Ana Mércia Fernandes, André Russowsky Brunoni, Bashar W. Badran, Clarice Tanaka, Daniel Ciampi De Andrade, Daniel Gomes Da Silva Machado, Edgard Morya, Eduardo Trujillo, Jaiti K. Swami, Joan A. Camprodon, Katia Monte-Silva, Katia Nunes Sá, Isadora Nunes, Juliana Barbosa Goulardins, Marom Bikson, Pedro Sudbrack-Oliveira, Priscila De Carvalho, Rafael Jardim Duarte-Moreira, Rosana Lima Pagano, Samuel Katsuyuki Shinjo, Yossi Zana

Publications and Research

Background: Novel coronavirus disease (COVID-19) morbidity is not restricted to the respiratory system, but also affects the nervous system. Non-invasive neuromodulation may be useful in the treatment of the disorders associated with COVID-19.

Objective: To describe the rationale and empirical basis of the use of non-invasive neuromodulation in the management of patients with COVID-10 and related disorders.

Methods: We summarize COVID-19 pathophysiology with emphasis of direct neuroinvasiveness, neuroimmune response and inflammation, autonomic balance and neurological, musculoskeletal and neuropsychiatric sequela. This supports the development of a framework for advancing applications of non-invasive neuromodulation in the management COVID-19 and related disorders.

Results: …

Update On The Use Of Transcranial Electrical Brain Stimulation To Manage Acute And Chronic Covid-19 Symptoms, Giuseppina Pilloni, Marom Bikson, Bashar W. Badran, Mark S. George, Steven A. Kautz, Alexandre Hideki Okano, Abrahão Fontes Baptista, Leigh E. Charvet

Publications and Research

The coronavirus disease 19 (COVID-19) pandemic has resulted in the urgent need to develop and deploy treatment approaches that can minimize mortality and morbidity. As infection, resulting illness, and the often prolonged recovery period continue to be characterized, therapeutic roles for transcranial electrical stimulation (tES) have emerged as promising non-pharmacological interventions. tES techniques have established therapeutic potential for managing a range of conditions relevant to COVID-19 illness and recovery, and may further be relevant for the general management of increased mental health problems during this time. Furthermore, these tES techniques can be inexpensive, portable, and allow for trained self-administration. Here, …

A Study Of The Relationship Between Uric Acid And Substantia Nigra Brain Connectivity In Patients With Rem Sleep Behavior Disorder And Parkinson’S Disease, Timothy M. Ellmore, Jessika Suescun, Richard J. Castriotta, Mya C. Schiess

Publications and Research

Low levels of the natural antioxidant uric acid (UA) and the presence of REM sleep behavior disorder (RBD) are both associated with an increased likelihood of developing Parkinson’s disease (PD). RBD and PD are also accompanied by basal ganglia dysfunction including decreased nigrostriatal and nigrocortical resting state functional connectivity. Despite these independent findings, the relationship between UA and substantia nigra (SN) functional connectivity remains unknown. In the present study, voxelwise analysis of covariance was used in a cross-sectional design to explore the relationship between UA and whole-brain SN functional connectivity using the eyes-open resting state fMRI method in controls without …

Two Nights Of Recovery Sleep Restores Hippocampal Connectivity But Not Episodic Memory After Total Sleep Deprivation, Ya Chai, Zhuo Fang, Fan Nils Yang, Sihua Xu, Yao Deng, Andrew Raine, Jieqiong Wang, Meichen Yu, Mathias Basner, Namni Goel, Junghoon J. Kim, David A. Wolk, John A. Detre, David F. Dinges, Hengyi Rao

Publications and Research

Sleep deprivation significantly impairs a range of cognitive and brain function, particularly episodic memory and the underlying hippocampal function. However, it remains controversial whether one or two nights of recovery sleep following sleep deprivation fully restores brain and cognitive function. In this study, we used functional magnetic resonance imaging (fMRI) and examined the effects of two consecutive nights (20-hour time-in-bed) of recovery sleep on resting-state hippocampal connectivity and episodic memory deficits following one night of total sleep deprivation (TSD) in 39 healthy adults in a controlled in-laboratory protocol. TSD significantly reduced memory performance in a scene recognition task, impaired hippocampal …

Transcutaneous Auricular Vagus Nerve Stimulation-Paired Rehabilitation For Oromotor Feeding Problems In Newborns: An Open-Label Pilot Study, Bashar W. Badran, Dorothea D. Jenkins, Daniel Cook, Sean Thompson, Morgan Darcy, William H. Devries, Georgia Mappin, Philipp Summers, Marom Bikson, Mark S. George

Publications and Research

Neonates born premature or who suffer brain injury at birth often have oral feeding dysfunction and do not meet oral intake requirements needed for discharge. Low oral intake volumes result in extended stays in the hospital (>2 months) and can lead to surgical implant and explant of a gastrostomy tube (G-tube). Prior work suggests pairing vagus nerve stimulation (VNS) with motor activity accelerates functional improvements after stroke, and transcutaneous auricular VNS (taVNS) has emerged as promising noninvasive form of VNS. Pairing taVNS with bottle-feeding rehabilitation may improve oromotor coordination and lead to improved oral intake volumes, ultimately avoiding the …

Modeling Interval Timing By Recurrent Neural Nets, Theodore Raphan, Eugene Dorokhin, Andrew R. Delamater

Publications and Research

The purpose of this study was to take a new approach in showing how the central nervous system might encode time at the supra-second level using recurrent neural nets (RNNs). This approach utilizes units with a delayed feedback, whose feedback weight determines the temporal properties of specific neurons in the network architecture. When these feedback neurons are coupled, they form a multilayered dynamical system that can be used to model temporal responses to steps of input in multidimensional systems. The timing network was implemented using separate recurrent “Go” and “NoGo” neural processing units to process an individual stimulus indicating the …

Immediate Neurophysiological Effects Of Transcranial Electrical Stimulation, Anli Liu, Mihály Vöröslakos, Gregory Kronberg, Simon Henin, Matthew R. Krause, Yu Huang, Alexander Opitz, Ashesh Mehta, Christopher C. Pack, Bart Krekelberg, Antal Berényi, Lucas C. Parra, Lucia Melloni, Orrin Devinsky, György Buzsáki

Publications and Research

Noninvasive brain stimulation techniques are used in experimental and clinical fields for their potential effects on brain network dynamics and behavior. Transcranial electrical stimulation (TES), including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), has gained popularity because of its convenience and potential as a chronic therapy. However, a mechanistic understanding of TES has lagged behind its widespread adoption. Here, we review data and modelling on the immediate neurophysiological effects of TES in vitro as well as in vivo in both humans and other animals. While it remains unclear how typical TES protocols affect neural activity, we …

Increased Excitability Induced In The Primary Motor Cortex By Transcranial Ultrasound Stimulation, Benjamin C. Gibson, Joseph L. Sanguinetti, Bashar W. Badran, Alfred B. Yu, Evan P. Klein, Christopher C. Abbott, Jeffrey T. Hansberger, Vincent P. Clark

Publications and Research

Background: Transcranial Ultrasound Stimulation (tUS) is an emerging technique that uses ultrasonic waves to noninvasively modulate brain activity. As with other forms of non-invasive brain stimulation (NIBS), tUS may be useful for altering cortical excitability and neuroplasticity for a variety of research and clinical applications. The effects of tUS on cortical excitability are still unclear, and further complications arise from the wide parameter space offered by various types of devices, transducer arrangements, and stimulation protocols. Diagnostic ultrasound imaging devices are safe, commonly available systems that may be useful for tUS. However, the feasibility of modifying brain activity with diagnostic tUS …

Manipulation Of Human Verticality Using High-Definition Transcranial Direct Current Stimulation, Taiza E. G. Santos, Diandra B. Favoretto, Iman Ghodratti Toostani, Diego C. Nascimento, Brunna P. Rimoli, Eduardo Bergonzoni, Tenysson Will Lemos, Dennis Quangvinh Truong, Alexandre C. B. Delbem, Bahador Makkiabadi, Renato Moraes, Francisco Louzada, Marom Bikson, Joao P. Leite, Dylan J. Edwards

Publications and Research

Background: Using conventional tDCS over the temporo-parietal junction (TPJ) we previously reported that it is possible to manipulate subjective visual vertical (SVV) and postural control. We also demonstrated that high-definition tDCS (HD-tDCS) can achieve substantially greater cortical stimulation focality than conventional tDCS. However, it is critical to establish dose-response effects using well-defined protocols with relevance to clinically meaningful applications.

Objective: To conduct three pilot studies investigating polarity and intensity-dependent effects of HD-tDCS over the right TPJ on behavioral and physiological outcome measures in healthy subjects. We additionally aimed to establish the feasibility, safety, and tolerability of this stimulation protocol.

Methods: …

Dual Inhibition Of Bcl-2/Bcl-Xl And Xpo1 Is Synthetically Lethal In Glioblastoma Model Systems, Enyuan Shang, Yiru Zhang, Chang Shu, Chiaki Tsuge Ishida, Elena Bianchetti, Mike-Andrew Westhoff, Georg Karpel-Massler, Markus D. Siegelin

Publications and Research

XPO1 has recently emerged as a viable treatment target for solid malignancies, including glioblastoma (GBM), the most common primary malignant brain tumor in adults. However, given that tumors become commonly resistant to single treatments, the identification of combination therapies is critical. Therefore, we tested the hypothesis that inhibition of anti-apoptotic Bcl-2 family members and XPO1 are synthetically lethal. To this purpose, two clinically validated drug compounds, the BH3-mimetic, ABT263, and the XPO1 inhibitor, Selinexor, were used in preclinical GBM model systems. Our results show that inhibition of XPO1 reduces cellular viability in glioblastoma cell cultures. Moreover, addition of ABT263 significantly …

Multiple Sclerosis Identification Based On Fractional Fourier Entropy And A Modified Jaya Algorithm, Shui-Hua Wang, Hong Cheng, Preetha Phillips, Yu-Dong Zhang

Publications and Research

Aim: Currently, identifying multiple sclerosis (MS) by human experts may come across the problem of “normal-appearing white matter”, which causes a low sensitivity. Methods: In this study, we presented a computer vision based approached to identify MS in an automatic way. This proposed method first extracted the fractional Fourier entropy map from a specified brain image. Afterwards, it sent the features to a multilayer perceptron trained by a proposed improved parameter-free Jaya algorithm. We used cost-sensitivity learning to handle the imbalanced data problem. Results: The 10 × 10-fold cross validation showed our method yielded a sensitivity of 97.40 ± 0.60%, …

Spinal Excitability Changes After Transspinal And Transcortical Paired Associative Stimulation In Humans, Maria Knikou

Publications and Research

Paired associative stimulation (PAS) produces enduring neuroplasticity based on Hebbian associative plasticity. This study established the changes in spinal motoneuronal excitability by pairing transcortical and transspinal stimulation. Transcortical stimulation was delivered after (transspinal-transcortical PAS) or before (transcortical-transspinal PAS) transspinal stimulation. Before and after 40 minutes of each PAS protocol, spinal neural excitability was assessed based on the amplitude of the transspinal-evoked potentials (TEPs) recorded from ankle muscles of both legs at different stimulation intensities (recruitment input-output curve). Changes in TEPs amplitude in response to low-frequency stimulation and paired transspinal stimuli were also established before and after each PAS protocol. TEP …

Coding Of Velocity Storage In The Vestibular Nuclei, Sergei B. Yakushin, Theodore Raphan, Bernard Cohen

Publications and Research

Semicircular canal afferents sense angular acceleration and output angular velocity with a short time constant of ≈4.5 s. This output is prolonged by a central integrative network, velocity storage that lengthens the time constants of eye velocity. This mechanism utilizes canal, otolith, and visual (optokinetic) information to align the axis of eye velocity toward the spatial vertical when head orientation is off-vertical axis. Previous studies indicated that vestibular-only (VO) and vestibular-pause-saccade (VPS) neurons located in the medial and superior vestibular nucleus could code all aspects of velocity storage. A recently developed technique enabled prolonged recording while animals were rotated and …

Beta Oscillatory Changes And Retention Of Motor Skills During Practice In Healthy Subjects And In Patients With Parkinson’S Disease, Aaron B. Nelson, Clara Moisello, Jing Lin, Priya Panday, Serena Ricci, Andrea Canessa, Alessandro Di Rocco, Angelo Quartarone, Giuseppe Frazzitta, Ioannis U. Isaias, Giulio Tononi, Chiara Cirelli, M. Felice Ghilardi

Publications and Research

Recently we found that modulation depth of beta power during movement increases with practice over sensory-motor areas in normal subjects but not in patients with Parkinson’s disease (PD). As such changesmight reflect use-dependentmodifications, we concluded that reduction of beta enhancement in PD represents saturation of cortical plasticity. A few questions remained open: What is the relation between these EEG changes and retention of motor skills? Would a second task exposure restore beta modulation enhancement in PD? Do practice-induced increases of beta modulation occur within each block? We thus recorded EEG in patients with PD and age-matched controls in two consecutive …

Persistent Amygdala Novelty Response Is Associated With Less Anterior Cingulum Integrity In Trauma-Exposed Women, Seungyeon A. Yoon, Mariann R. Weierich

Publications and Research

Objectives: We investigated the potential role of cingulum and uncinate fasciculus integrity in trauma-related neural hypervigilance, indexed by less discrimination between amygdala activation to novel and familiar affective images.

Participants: 22 women (mean age 21.7 ± 3.9 years) with a history of trauma, and 20 no-trauma controls (mean age 21.9 ± 4.8 years).

Measures: Trauma exposure and trauma-related symptoms were assessed during structured clinical interview. White matter integrity in the anterior cingulum, parahippocampal cingulum, and uncinate fasciculus was measured using diffusion weighted imaging. Amygdala response to novel and familiar affective scenes was measured with functional magnetic resonance imaging.

Results: Trauma-exposed …

Cerebellar Tdcs: A Novel Approach To Augment Language Treatment Post-Stroke, Rajani Sebastian, Sadhvi Saxena, Kyrana Tsapkini, Andreia V. Faria, Charltien Long, Amy Wright, Cameron Davis, Donna C. Tippett, Antonios P. Mourdoukoutas, Marom Bikson, Pablo Celnik, Argye E. Hillis

Publications and Research

People with post-stroke aphasia may have some degree of chronic deficit for which current rehabilitative treatments are variably effective. Accumulating evidence suggests that transcranial direct current stimulation (tDCS) may be useful for enhancing the effects of behavioral aphasia treatment. However, it remains unclear which brain regions should be stimulated to optimize effects on language recovery. Here, we report on the therapeutic potential of right cerebellar tDCS in augmenting language recovery in SMY, who sustained bilateral MCA infarct resulting in aphasia and anarthria. We investigated the effects of 15 sessions of anodal cerebellar tDCS coupled with spelling therapy using a randomized, …

Updating Temporal Expectancy Of An Aversive Event Engages Striatal Plasticity Under Amygdala Control, Glenn Dallérac, Michael Graupner, Jeroen Knippenberg, Raquel Chacon Ruiz Martinez, Tatiane Ferreira Tavares, Lucille Tallot, Nicole El Massioui, Anna Verschueren, Sophie Höhn, Julie Boulanger Bertolus, Alex D. Reyes, Joseph E. Ledoux, Glenn E. Schafe, Lorenzo Diaz-Mataix, Valérie Doyère

Publications and Research

Pavlovian aversive conditioning requires learning of the association between a conditioned stimulus (CS) and an unconditioned, aversive stimulus (US) but also involves encoding the time interval between the two stimuli. The neurobiological bases of this time interval learning are unknown. Here, we show that in rats, the dorsal striatum and basal amygdala belong to a common functional network underlying temporal expectancy and learning of a CS–US interval. Importantly, changes in coherence between striatum and amygdala local field potentials (LFPs) were found to couple these structures during interval estimation within the lower range of the theta rhythm (3–6 Hz). Strikingly, we …

Research Methods In Occupational Health Psychology, Irvin Sam Schonfeld, Chu-Hsiang Chang

Publications and Research

http://www.springerpub.com/occupational-health-psychology.html

Occupational Health Psychology (OHP) is a rapidly expanding interdisciplinary field that focuses on the science and practice of psychology in promoting and developing workplace health- and safety-related initiatives. This comprehensive text for undergraduate and graduate survey courses is the first to encompass a wide range of key issues in OHP. It draws from the domains of psychology, public health, preventive medicine,nursing, industrial engineering, law, and epidemiology to focus on the theory and practice of protecting and promoting the health, well-being, and safety of individuals in the workplace and improving the quality of work life.

The text addresses key psychosocial …

Striatal Dopaminergic Innervation Regulates Subthalamic Beta-Oscillations And Cortical-Subcortical Coupling During Movements: Preliminary Evidence In Subjects With Parkinson’S Disease, Andrea Canessa, Nicolo G. Pozzi, Gabriele Arnulfo, Joachim Brumberg, Martin M. Reich, Gianni Pezzoli, Maria F. Ghilardi, Cordula Matthies, Frank Steigerwald, Jens Volkman, Ioannis U. Isais

Publications and Research

Activation of the basal ganglia has been shown during the preparation and execution of movement. However, the functional interaction of cortical and subcortical brain areas during movement and the relative contribution of dopaminergic striatal innervation remains unclear. We recorded local field potential (LFP) activity from the subthalamic nucleus (STN) and high-density electroencephalography (EEG) signals in four patients with Parkinson’s disease (PD) off dopaminergic medication during a multi-joint motor task performed with their dominant and non-dominant hand. Recordings were performed by means of a fully-implantable deep brain stimulation (DBS) device at 4 months after surgery. Three patients also performed a single-photon …

Temporary Nerve Block At Selected Digits Revealed Hand Motor Deficits In Grasping Tasks, Aude Cateron, Kerry Mcpartlan, Christina Gioeli, Emily Reid, Matt Turturro, Barry Hahn, Cynthia Benson, Wei Zhang

Publications and Research

Peripheral sensory feedback plays a crucial role in ensuring correct motor execution throughout hand grasp control. Previous studies utilized local anesthesia to deprive somatosensory feedback in the digits or hand, observations included sensorimotor deficits at both corticospinal and peripheral levels. However, the questions of how the disturbed and intact sensory input integrate and interact with each other to assist the motor program execution, and whether the motor coordination based on motor output variability between affected and non-affected elements (e.g., digits) becomes interfered by the local sensory deficiency, have not been answered. The current study aims to investigate the effect of …

Direct Current-Induced Calcium Trafficking In Different Neuronal Preparations, Andrzej Wieraszko, Zaghloul Ahmed

Publications and Research

The influence of direct current (DC) stimulation on radioactive calcium trafficking in sciatic nerve in vivo and in vitro, spinal cord, and synaptosomes was investigated. The exposure to DC enhanced calcium redistribution in all of these preparations. The effect was dependent on the strength of the stimulation and extended beyond the phase of exposure to DC. The DC-induced increase in calcium sequestration by synaptosomes was significantly reduced by cobalt and rupture of synaptosomes by osmotic shock. Although both anodal and cathodal currents were effective, the experiments with two electrodes of different areas revealed that cathodal stimulation exerted stronger effect. The …

Abnormal Tau Induces Cognitive Impairment Through Two Different Mechanisms: Synaptic Dysfunction And Neuronal Loss, J. Di, L. S. Cohen, C. P. Corbo, Greg R. Phillips, Abdeslem El Idrissi, Alejandra D. Alonso

Publications and Research

The hyperphosphorylated microtubule-associated protein tau is present in several neurodegenerative diseases, although the causal relationship remains elusive. Few mouse models used to study Alzheimerlike dementia target tau phosphorylation. We created an inducible pseudophosphorylated tau (Pathological Human Tau, PH-Tau) mouse model to study the effect of conformationally modified tau in vivo. Leaky expression resulted in two levels of PH-Tau: low basal level and higher upon induction (4% and 14% of the endogenous tau, respectively). Unexpectedly, low PH-Tau resulted in significant cognitive deficits, decrease in the number of synapses (seen by EM in the CA1 region), reduction of synaptic proteins, and localization …

Utilizing Fast Spin Echo Mri To Reduce Image Artifacts And Improve Implant/Tissue Interface Detection In Refractory Parkinson’S Patients With Deep Brain Stimulators, Subhendra N. Sarkar, Pooja R. Sarkar, Efstathios Papavassiliou, Rafael Rojas

Publications and Research

Introduction. In medically refractory Parkinson’s disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detectDBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity.

Methods. Using an IRB approved protocol 8 advanced PDpatientswere imagedwithinMRconditional safety guidelines at lowRF power (SAR ≤ 0.1 W/kg) in coronal plane at 1.5T by various sequences.The image slices were subjectively evaluated for diagnostic quality and the lead contact diameters were compared to identify a sequence least affected by metallic leads.

Results …

Three‐Dimensional Brain Mri For Dbs Patients Within Ultra‐Low Radiofrequency Power Limits, Subhendra N. Sarkar, Efstathios Papavassiliou, David Hackney, David Alsop, Ananth Madhuranthakam, Ludy Shih, Reed Busse, Susan Laruche, Rafeeque Bhadelia

Publications and Research

Background: For patients with deep brain stimulators (DBS), local absorbed radiofrequency (RF) power is unknown and is much higher than what the system estimates. We developed a comprehensive, highquality brain magnetic resonance imaging (MRI) protocol for DBS patients utilizing three-dimensional (3D) magnetic resonance sequences at very low RF power. Methods: Six patients with DBS were imaged (10 sessions) using a transmit/receive head coil at 1.5 Tesla with modified 3D sequences within ultra-low specific absorption rate (SAR) limits (0.1 W/kg) using T2, fast fluid-attenuated inversion recovery (FLAIR) and T1- weighted image contrast. Tissue signal and tissue contrast from the low-SAR images …