An Integrative View of Tdcs-Induced Motor Cortex Modulation in Patients
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3D Histological Reconstruction of Fiber Tracts and Direct Comparison with Diffusion Tensor MRI Tractography
3D Histological Reconstruction of Fiber Tracts and Direct Comparison with Diffusion Tensor MRI Tractography Julien Dauguet1, Sharon Peled2, Vladimir Berezovskii3, Thierry Delzescaux4, Simon K. Warfield1, Richard Born3, and Carl-Fredrik Westin5 1 Computational Radiology Laboratory, Children’s Hospital, Brigham and Women’s Hospital, Harvard Medical School, Boston, USA 2 Harvard Center for Neurodegeneration and Repair, Boston, USA 3 Department of Neurobiology, Harvard Medical School, Boston, USA 4 Service Hospitalier Fr´ed´eric Joliot, CEA, Orsay, France 5 Laboratory of Mathematics in Imaging, Brigham and Women’s Hospital, Harvard Medical School, Boston, USA Abstract. A classical neural tract tracer, WGA-HRP, was injected at multiple sites within the brain of a macaque monkey. Histological sections of the labeled fiber tracts were reconstructed in 3D, and the fibers were segmented and registered with the anatomical post-mortem MRI from the same animal. Fiber tracing along the same pathways was performed on the DTI data using a classical diffusion tracing technique. The fibers derived from the DTI were compared with those segmented from the histology in order to evaluate the performance of DTI fiber tracing. While there was generally good agreement between the two methods, our results reveal certain limitations of DTI tractography, particularly at regions of fiber tract crossing or bifurcation. 1 Introduction Tracing neural connections lies at the heart of neuroanatomy, and has profound implications for the study of neural function and for the study of developmental and adult plasticity of the nervous system. It is also important for the study of neurodegenerative diseases, and for the planning of neurosurgical procedures, such as tumor ablation. -
Chapter 8 Nervous System
Chapter 8 Nervous System I. Functions A. Sensory Input – stimuli interpreted as touch, taste, temperature, smell, sound, blood pressure, and body position. B. Integration – CNS processes sensory input and initiates responses categorizing into immediate response, memory, or ignore C. Homeostasis – maintains through sensory input and integration by stimulating or inhibiting other systems D. Mental Activity – consciousness, memory, thinking E. Control of Muscles & Glands – controls skeletal muscle and helps control/regulate smooth muscle, cardiac muscle, and glands II. Divisions of the Nervous system – 2 anatomical/main divisions A. CNS (Central Nervous System) – consists of the brain and spinal cord B. PNS (Peripheral Nervous System) – consists of ganglia and nerves outside the brain and spinal cord – has 2 subdivisions 1. Sensory Division (Afferent) – conducts action potentials from PNS toward the CNS (by way of the sensory neurons) for evaluation 2. Motor Division (Efferent) – conducts action potentials from CNS toward the PNS (by way of the motor neurons) creating a response from an effector organ – has 2 subdivisions a. Somatic Motor System – controls skeletal muscle only b. Autonomic System – controls/effects smooth muscle, cardiac muscle, and glands – 2 branches • Sympathetic – accelerator “fight or flight” • Parasympathetic – brake “resting and digesting” * 4 Types of Effector Organs: skeletal muscle, smooth muscle, cardiac muscle, and glands. III. Cells of the Nervous System A. Neurons – receive stimuli and transmit action potentials -
Functional Role of the Supplementary and Pre-Supplementary Motor Areas
REVIEWS Functional role of the supplementary and pre-supplementary motor areas Parashkev Nachev*‡, Christopher Kennard‡ and Masud Husain* Abstract | The supplementary motor complex consists of the supplementary motor area, the supplementary eye field and the pre-supplementary motor area. In recent years, these areas have come under increasing scrutiny from cognitive neuroscientists, motor physiologists and clinicians because they seem to be crucial for linking cognition to action. However, theories regarding their function vary widely. This Review brings together the data regarding the supplementary motor regions, highlighting outstanding issues and providing new perspectives for understanding their functions. Ever since they were first identified, the regions that which we hope will stimulate the development of comprise the supplementary motor complex (SMC) have conceptual frameworks for a better understanding remained, in large part, a mystery. Most investigators now of this region. appreciate that these brain regions are far from ‘supple- mentary’ to requirements1–7. Without them, there are Anatomy and connections profound alterations in behaviour. For example, lesions to The supplementary motor area (SMA) and pre- these areas in humans can lead to alien-limb syndrome, supplementary motor area (pre-SMA) are, in humans, with patients demonstrating involuntary actions such as located on the medial aspect of the brain: in the dorso- grasping nearby objects — even other people — without medial frontal cortex3,14, anterior to the leg representa- ever intending to do so8,9. Some individuals demonstrate tion of the primary motor cortex (FIG. 1). Both areas lie utilization behaviour: unable to resist the impulse to use in the superior frontal gyrus and constitute the medial an object that has been placed within their reach, even part of Brodmann’s area 6c (later divided into two areas: when the object is not needed10. -
A Core Speech Circuit Between Primary Motor, Somatosensory, and Auditory Cortex
bioRxiv preprint doi: https://doi.org/10.1101/139550; this version posted May 19, 2017. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Speech core 1 A core speech circuit between primary motor, somatosensory, and auditory cortex: Evidence from connectivity and genetic descriptions * ^ Jeremy I Skipper and Uri Hasson * Experimental Psychology, University College London, UK ^ Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy, and Center for Practical Wisdom, Dept. of Psychology, The University of Chicago Running title: Speech core Words count: 20,362 Address correspondence to: Jeremy I Skipper University College London Experimental Psychology 26 Bedford Way London WC1H OAP United Kingdom E-mail: [email protected] bioRxiv preprint doi: https://doi.org/10.1101/139550; this version posted May 19, 2017. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Speech core 2 Abstract What adaptations allow humans to produce and perceive speech so effortlessly? We show that speech is supported by a largely undocumented core of structural and functional connectivity between the central sulcus (CS or primary motor and somatosensory cortex) and the transverse temporal gyrus (TTG or primary auditory cortex). Anatomically, we show that CS and TTG cortical thickness covary across individuals and that they are connected by white matter tracts. -
The Prefrontal Cortex
Avens Publishing Group Inviting Innovations Open Access Review Article J Hum Anat Physiol July 2017 Volume:1, Issue:1 © All rights are reserved by Ogeturk. AvensJournal Publishing of Group Inviting Innovations Human Anatomy The Prefrontal Cortex: A Basic & Physiology Embryological, Histological, Anatomical, and Functional Ramazan Fazıl Akkoc and Murat Ogeturk* Department of Anatomy, Firat University, Turkey Guideline *Address for Correspondence Murat Ogeturk, Firat University, Faculty of Medicine, 23119 Elazig, Turkey, Tel: +90-424-2370000 (ext: 4654); Fax: +90-424-2379138; Keywords: Prefrontal cortex; Working memory; Frontal lobe E-Mail: [email protected] Abstract Submission: 24 May, 2017 Accepted: 11 July, 2017 The prefrontal cortex (PFC) unites, processes and controls the Published: 19 August, 2017 information coming from cortex and subcortical structures, and Copyright: © 2017 Akkoc RF. This is an open access article distributed decides and executes goal-oriented behavior. A major function of PFC under the Creative Commons Attribution License, which permits is to maintain the attention. Furthermore, it has many other functions unrestricted use, distribution, and reproduction in any medium, provided including working memory, problem solving, graciousness, memory, the original work is properly cited. and intellectuality. PFC is well developed in humans and localized to the anterior of the frontal lobe. This article presents a systematic review and detailed summary of embryology, histology, anatomy, functions and lesions of PFC. I. Lamina zonalis: Contains few Cajal horizontal cells. The axons of Martinotti cells located at deep layers, the last branches of the apical dendrites of pyramidal cells, and the last branches Introduction of the afferent nerve fibers extend to this lamina. -
Short- and Long-Term Deficits After Unilateral Ablation Andthe Effects of Subsequent Callosal Section’
0270.6474/84/0404-0918$02.00/0 The Journal of Neuroscience Copyright 0 Society for Neuroscience Vol. 4, No. 4, pp. 918-929 Printed in U.S.A. April 1984 SUPPLEMENTARY MOTOR AREA OF THE MONKEY’S CEREBRAL CORTEX: SHORT- AND LONG-TERM DEFICITS AFTER UNILATERAL ABLATION ANDTHE EFFECTS OF SUBSEQUENT CALLOSAL SECTION’ COBIE BRINKMAN Experimental Neurology Unit, The John Curtin School of Medical Research, Australian National University, Canberra, Australia 2601 Received March 7, 1983; Revised November 11, 1983; Accepted November 15, 1983 Abstract The short-term and long-term behavioral effects of unilateral lesions of the supplementary motor area (SMA) were studied in five monkeys (Mczcaca fascicularis ssp). A monkey with a unilateral lesion of the premotor area (PM) served as a control. In all animals, general behavior was unaffected by the lesions. For a few weeks postoperatively, all monkeys showed a clumsiness of forelimb movements, bilaterally, which involved both the distal and proximal muscles. Two SMA-lesioned monkeys (but not the PM-lesioned one), studied for up to 1 year postoperatively, showed a characteristic deficit of bimanual coordination where the two hands tended to behave in a similar manner instead of sharing the task between them. This deficit was more pronounced after a lesion contralateral to the nonpreferred hand. The deficit was interpreted as indicating that the intact SMA now influenced the motor outflow of both the ipsilateral hemisphere and the contralateral one through the corpus callosum. Callosal section immediately abolished the bimanual deficit, although the clumsiness returned transiently. The results imply that SMA may give rise normally to discharges informing the contralateral hemisphere of intended and/or ongoing movements via the corpus callosum. -
Down but Not out in Posterior Cingulate Cortex: Deactivation Yet Functional Coupling with Prefrontal Cortex During Demanding Semantic Cognition
NeuroImage 141 (2016) 366–377 Contents lists available at ScienceDirect NeuroImage journal homepage: www.elsevier.com/locate/ynimg Down but not out in posterior cingulate cortex: Deactivation yet functional coupling with prefrontal cortex during demanding semantic cognition Katya Krieger-Redwood ⁎, Elizabeth Jefferies, Theodoros Karapanagiotidis, Robert Seymour, Adonany Nunes, Jit Wei Aaron Ang, Vierra Majernikova, Giovanna Mollo, Jonathan Smallwood Department of Psychology/York Neuroimaging Centre, University of York, Heslington, York, United Kingdom article info abstract Article history: The posterior cingulate cortex (pCC) often deactivates during complex tasks, and at rest is often only weakly cor- Received 30 March 2016 related with regions that play a general role in the control of cognition. These observations led to the hypothesis Accepted 29 July 2016 that pCC contributes to automatic aspects of memory retrieval and cognition. Recent work, however, has sug- Available online 30 July 2016 gested that the pCC may support both automatic and controlled forms of memory processing and may do so by changing its communication with regions that are important in the control of cognition across multiple do- Keywords: mains. The current study examined these alternative views by characterising the functional coupling of the Posterior cingulate cortex Dorsolateral prefrontal cortex pCC in easy semantic decisions (based on strong global associations) and in harder semantic tasks (matching Semantic control words on the basis of specific non-dominant features). Increasingly difficult semantic decisions led to the expect- Executive ed pattern of deactivation in the pCC; however, psychophysiological interaction analysis revealed that, under Rest these conditions, the pCC exhibited greater connectivity with dorsolateral prefrontal cortex (PFC), relative to Connectivity both easier semantic decisions and to a period of rest. -
Cortex Brainstem Spinal Cord Thalamus Cerebellum Basal Ganglia
Harvard-MIT Division of Health Sciences and Technology HST.131: Introduction to Neuroscience Course Director: Dr. David Corey Motor Systems I 1 Emad Eskandar, MD Motor Systems I - Muscles & Spinal Cord Introduction Normal motor function requires the coordination of multiple inter-elated areas of the CNS. Understanding the contributions of these areas to generating movements and the disturbances that arise from their pathology are important challenges for the clinician and the scientist. Despite the importance of diseases that cause disorders of movement, the precise function of many of these areas is not completely clear. The main constituents of the motor system are the cortex, basal ganglia, cerebellum, brainstem, and spinal cord. Cortex Basal Ganglia Cerebellum Thalamus Brainstem Spinal Cord In very broad terms, cortical motor areas initiate voluntary movements. The cortex projects to the spinal cord directly, through the corticospinal tract - also known as the pyramidal tract, or indirectly through relay areas in the brain stem. The cortical output is modified by two parallel but separate re entrant side loops. One loop involves the basal ganglia while the other loop involves the cerebellum. The final outputs for the entire system are the alpha motor neurons of the spinal cord, also called the Lower Motor Neurons. Cortex: Planning and initiation of voluntary movements and integration of inputs from other brain areas. Basal Ganglia: Enforcement of desired movements and suppression of undesired movements. Cerebellum: Timing and precision of fine movements, adjusting ongoing movements, motor learning of skilled tasks Brain Stem: Control of balance and posture, coordination of head, neck and eye movements, motor outflow of cranial nerves Spinal Cord: Spontaneous reflexes, rhythmic movements, motor outflow to body. -
Cerebral Cortex
Cerebral Cortex • Research on the structure and function of the brain reveals that there are both specialized and diffuse areas of function • Motor and sensory areas are localized in discrete cortical areas called domains • Many higher mental functions such as memory and language appear to have overlapping domains and are more diffusely located • Broadmann areas are areas of localized function Cerebral Cortex - Generalizations • The cerebral cortex has three types of functional areas – Motor areas / control voluntary motor function – Sensory areas / provide conscious awareness of sensation – Association areas / act mainly to integrate diverse information for purposeful action • Each hemisphere is chiefly concerned with the sensory and motor functions of the opposite (contralateral) side of the body Motor Areas • Cortical areas controlling motor functions lie in the posterior part of the frontal lobes • Motor areas include the primary motor cortex, the premotor cortex, Broca’s area, and the front eye field Primary Motor Cortex • The primary motor cortex is located in the precentral gyrus of the frontal lobe of each hemisphere • Large neurons (pyramidal cells) in these gyri allow us to consciously control the precise or skill voluntary movements of our skeletal muscles Pyramidal cells • These long axons, which project to the spinal cord, form the massive Dendrites voluntary motor tracts called the pyramidal, or corticospinal tracts • All other descending motor tracts issue from brain stem nuclei and consists of chains of two, three, or -
A Practical Review of Functional MRI Anatomy of the Language and Motor Systems
REVIEW ARTICLE FUNCTIONAL A Practical Review of Functional MRI Anatomy of the Language and Motor Systems X V.B. Hill, X C.Z. Cankurtaran, X B.P. Liu, X T.A. Hijaz, X M. Naidich, X A.J. Nemeth, X J. Gastala, X C. Krumpelman, X E.N. McComb, and X A.W. Korutz ABSTRACT SUMMARY: Functional MR imaging is being performed with increasing frequency in the typical neuroradiology practice; however, many readers of these studies have only a limited knowledge of the functional anatomy of the brain. This text will delineate the locations, anatomic boundaries, and functions of the cortical regions of the brain most commonly encountered in clinical practice—specifically, the regions involved in movement and language. ABBREVIATIONS: FFA ϭ fusiform face area; IPL ϭ inferior parietal lobule; PPC ϭ posterior parietal cortex; SMA ϭ supplementary motor area; VOTC ϭ ventral occipitotemporal cortex his article serves as a review of the functional areas of the brain serving to analyze spatial position and the ventral stream working Tmost commonly mapped during presurgical fMRI studies, to identify what an object is. Influenced by the dorsal and ventral specifically targeting movement and language. We have compiled stream model of vision, Hickok and Poeppel2 hypothesized a sim- what we hope is a useful, easily portable, and concise resource that ilar framework for language. In this model, the ventral stream, or can be accessible to radiologists everywhere. We begin with a re- lexical-semantic system, is involved in sound-to-meaning map- view of the language-processing system. Then we describe the pings associated with language comprehension and semantic ac- gross anatomic boundaries, organization, and function of each cess. -
Cortical Parcellation Protocol
CORTICAL PARCELLATION PROTOCOL APRIL 5, 2010 © 2010 NEUROMORPHOMETRICS, INC. ALL RIGHTS RESERVED. PRINCIPAL AUTHORS: Jason Tourville, Ph.D. Research Assistant Professor Department of Cognitive and Neural Systems Boston University Ruth Carper, Ph.D. Assistant Research Scientist Center for Human Development University of California, San Diego Georges Salamon, M.D. Research Dept., Radiology David Geffen School of Medicine at UCLA WITH CONTRIBUTIONS FROM MANY OTHERS Neuromorphometrics, Inc. 22 Westminster Street Somerville MA, 02144-1630 Phone/Fax (617) 776-7844 neuromorphometrics.com OVERVIEW The cerebral cortex is divided into 49 macro-anatomically defined regions in each hemisphere that are of broad interest to the neuroimaging community. Region of interest (ROI) boundary definitions were derived from a number of cortical labeling methods currently in use. Protocols from the Laboratory of Neuroimaging at UCLA (LONI; Shattuck et al., 2008), the University of Iowa Mental Health Clinical Research Center (IOWA; Crespo-Facorro et al., 2000; Kim et al., 2000), the Center for Morphometric Analysis at Massachusetts General Hospital (MGH-CMA; Caviness et al., 1996), a collaboration between the Freesurfer group at MGH and Boston University School of Medicine (MGH-Desikan; Desikan et al., 2006), and UC San Diego (Carper & Courchesne, 2000; Carper & Courchesne, 2005; Carper et al., 2002) are specifically referenced in the protocol below. Methods developed at Boston University (Tourville & Guenther, 2003), Brigham and Women’s Hospital (McCarley & Shenton, 2008), Stanford (Allan Reiss lab), the University of Maryland (Buchanan et al., 2004), and the University of Toyoma (Zhou et al., 2007) were also consulted. The development of the protocol was also guided by the Ono, Kubik, and Abernathy (1990), Duvernoy (1999), and Mai, Paxinos, and Voss (Mai et al., 2008) neuroanatomical atlases. -
Cortical and Subcortical Anatomy: Basics and Applied
43rd Congress of the Canadian Neurological Sciences Federation Basic mechanisms of epileptogenesis and principles of electroencephalography Cortical and subcortical anatomy: basics and applied J. A. Kiernan MB, ChB, PhD, DSc Department of Anatomy & Cell Biology, The University of Western Ontario London, Canada LEARNING OBJECTIVES Know and understand: ! Two types of principal cell and five types of interneuron in the cerebral cortex. ! The layers of the cerebral cortex as seen in sections stained to show either nucleic acids or myelin. ! The types of corrtex: allocortex and isocortex. ! Major differences between extreme types of isocortex. As seen in primary motor and primary sensory areas. ! Principal cells in different layers give rise to association, commissural, projection and corticothalamic fibres. ! Cortical neurons are arranged in columns of neurons that share the same function. ! Intracortical circuitry provides for neurons in one column to excite one another and to inhibit neurons in adjacent columns. ! The general plan of neuronal connections within nuclei of the thalamus. ! The location of motor areas of the cerebral cortex and their parallel and hierarchical projections to the brain stem and spinal cord. ! The primary visual area and its connected association areas, which have different functions. ! Somatotopic representation in the primary somatosensory and motor areas. ! Cortical areas concerned with perception and expression of language, and the anatomy of their interconnections. DISCLOSURE FORM This disclosure form must be included as the third page of your Course Notes and the third slide of your presentation. It is the policy of the Canadian Neurological Sciences Federation to insure balance, independence, objectivity and scientific rigor in all of its education programs.