Dynamic Modulation of Decision Biases by Brainstem Arousal Systems
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Magnetic Resonance Imaging of Multiple Sclerosis: a Study of Pulse-Technique Efficacy
691 Magnetic Resonance Imaging of Multiple Sclerosis: A Study of Pulse-Technique Efficacy Val M. Runge1 Forty-two patients with the clinical diagnosis of multiple sclerosis were examined by Ann C. Price1 proton magnetic resonance imaging (MRI) at 0.5 T. An extensive protocol was used to Howard S. Kirshner2 facilitate a comparison of the efficacy of different pulse techniques. Results were also Joseph H. Allen 1 compared in 39 cases with high-resolution x-ray computed tomography (CT). MRI revealed characteristic abnormalities in each case, whereas CT was positive in only 15 C. Leon Partain 1 of 33 patients. Milder grades 1 and 2 disease were usually undetected by CT, and in all A. Everette James, Jr.1 cases, the abnormalities noted on MRI were much more extensive than on CT. Cerebral abnormalities were best shown with the T2-weighted spin-echo sequence (TE/TR = 120/1000); brainstem lesions were best defined on the inversion-recovery sequence (TE/TI/TR =30/400/1250). Increasing TE to 120 msec and TR to 2000 msec heightened the contrast between normal and abnormal white matter. However, the signal intensity of cerebrospinal fluid with this pulse technique obscured some abnormalities. The diagnosis of multiple sclerosis continues to be a clinical challenge [1,2). The lack of an objective means of assessment further complicates the evaluation of treatment regimens. Evoked potentials, cerebrospinal fluid (CSF) analysis , and computed tomography (CT) are currently used for diagnosis, but all lack sensitivity and/or specificity. Furthermore, postmortem examinations demonstrate many more lesions than those suggested by clinical means [3). -
Brainstem: Structure & Its Mode of Action
Journal of Neurology & Neurophysiology 2021, Vol.12, Issue 3, 521 Opinion Brainstem: Structure & Its Mode of action Karthikeyan Rupani Research Fellow, Tata Medical Centre, India. Corresponding Author* The brainstem is exceptionally little, making up around as it were 2.6 percent of the brain's add up to weight. It has the basic parts of directing cardiac, and Rupani K, respiratory work, making a difference to control heart rate and breathing rate. Research Fellow, Tata Medical Centre, India; It moreover gives the most engine and tactile nerve supply to the confront and E-mail: [email protected] neck by means of the cranial nerves. Ten sets of cranial nerves come from the brainstem. Other parts incorporate the direction of the central apprehensive Copyright: 2021 Rupani K. This is an open-access article distributed under the framework and the body's sleep cycle. It is additionally of prime significance terms of the Creative Commons Attribution License, which permits unrestricted within the movement of engine and tangible pathways from the rest of the use, distribution, and reproduction in any medium, provided the original author brain to the body, and from the body back to the brain. These pathways and source are credited. incorporate the corticospinal tract (engine work), the dorsal column-medial lemniscus pathway and the spinothalamic tract [3]. The primary part of the brainstem we'll consider is the midbrain. The midbrain Received 01 March 2021; Accepted 15 March 2021; Published 22 March 2021 (too known as the mesencephalon) is the foremost prevalent of the three districts of the brainstem. It acts as a conduit between the forebrain over and the pons and cerebellum underneath. -
Imaging Retinotopic Maps in the Human Brain ⇑ Brian A
Vision Research 51 (2011) 718–737 Contents lists available at ScienceDirect Vision Research journal homepage: www.elsevier.com/locate/visres Review Imaging retinotopic maps in the human brain ⇑ Brian A. Wandell , Jonathan Winawer Psychology Department, Stanford University, Stanford, CA 94305, United States article info abstract Article history: A quarter-century ago visual neuroscientists had little information about the number and organization of Received 5 April 2010 retinotopic maps in human visual cortex. The advent of functional magnetic resonance imaging (MRI), a Received in revised form 2 August 2010 non-invasive, spatially-resolved technique for measuring brain activity, provided a wealth of data about Available online 6 August 2010 human retinotopic maps. Just as there are differences amongst non-human primate maps, the human maps have their own unique properties. Many human maps can be measured reliably in individual sub- Keywords: jects during experimental sessions lasting less than an hour. The efficiency of the measurements and the Visual field maps relatively large amplitude of functional MRI signals in visual cortex make it possible to develop quanti- Retinotopy tative models of functional responses within specific maps in individual subjects. During this last quarter- Human visual cortex Functional specialization century, there has also been significant progress in measuring properties of the human brain at a range of Optic radiation length and time scales, including white matter pathways, macroscopic properties of gray and white mat- Visual field map clusters ter, and cellular and molecular tissue properties. We hope the next 25 years will see a great deal of work that aims to integrate these data by modeling the network of visual signals. -
Interaction Among Ocularity, Retinotopy and On-Center/Off Center Pathways During Development
INTERACTION AMONG OCULARITY, RETINOTOPY AND ON-CENTER/OFF CENTER PATHWAYS DURING DEVELOPMENT Shigeru Tanaka Fundamental Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305, Japan ABSTRACT The development of projections from the retinas to the cortex is mathematically analyzed according to the previously proposed thermodynamic formulation of the self-organization of neural networks. Three types of submodality included in the visual afferent pathways are assumed in two models: model (A), in which the ocularity and retinotopy are considered separately, and model (B), in which on-center/off-center pathways are considered in addition to ocularity and retinotopy. Model (A) shows striped ocular dominance spatial patterns and, in ocular dominance histograms, reveals a dip in the binocular bin. Model (B) displays spatially modulated irregular patterns and shows single-peak behavior in the histograms. When we compare the simulated results with the observed results, it is evident that the ocular dominance spatial patterns and histograms for models (A) and (B) agree very closely with those seen in monkeys and cats. 1 INTRODUCTION A recent experimental study has revealed that spatial patterns of ocular dominance columns (ODes) observed by autoradiography and profiles of the ocular dominance histogram (ODH) obtained by electrophysiological experiments differ greatly between monkeys and cats. ODes for cats in the tangential section appear as beaded patterns with an irregularly fluctuating bandwidth (Anderson, Olavarria and Van Sluyters 1988); ODes for monkeys are likely to be straight parallel stripes (Hubel, Wiesel and LeVay, 1977). The typical ODH for cats has a single peak in the middle of the ocular dominance corresponding to balanced response in ocularity (Wiesel and Hubel, 1974). -
Retinotopy Versus Face Selectivity in Macaque Visual Cortex
Retinotopy versus Face Selectivity in Macaque Visual Cortex Reza Rajimehr1,2, Natalia Y. Bilenko1, Wim Vanduffel1,3, 1 and Roger B. H. Tootell Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/26/12/2691/1782578/jocn_a_00672.pdf by MIT Libraries user on 17 May 2021 Abstract ■ Retinotopic organization is a ubiquitous property of lower- Distinct subregions within face-selective patches showed tier visual cortical areas in human and nonhuman primates. In either (1) a coarse retinotopic map of eccentricity and polar macaque visual cortex, the retinotopic maps extend to higher- angle, (2) a retinotopic bias to a specific location of visual order areas in the ventral visual pathway, including area TEO field, or (3) nonretinotopic selectivity. In general, regions in the inferior temporal (IT) cortex. Distinct regions within IT along the lateral convexity of IT cortex showed more overlap cortex are also selective to specific object categories such as between retinotopic maps and face selectivity, compared with faces. Here we tested the topographic relationship between regions within the STS. Thus, face patches in macaques can be retinotopic maps and face-selective patches in macaque visual subdivided into smaller patches with distinguishable retino- cortex using high-resolution fMRI and retinotopic face stimuli. topic properties. ■ INTRODUCTION has been recently challenged by the demonstration of small Visual cortical areas are typically defined on the basis of receptive fields in anterior IT cortex (DiCarlo & Maunsell, differences in histology (cytoarchitecture and myelo- 2003; Op De Beeck & Vogels, 2000). architecture), anatomical connections, functional proper- How do the retinotopic maps in IT cortex relate to ties, and retinotopic organization (Felleman & Van Essen, the functionally defined category-selective areas? Neuro- 1991). -
Preference for Concentric Orientations in the Mouse Superior Colliculus
ARTICLE Received 12 Jan 2015 | Accepted 25 Feb 2015 | Published 2 Apr 2015 DOI: 10.1038/ncomms7773 OPEN Preference for concentric orientations in the mouse superior colliculus Mehran Ahmadlou1 & J Alexander Heimel1 The superior colliculus is a layered structure important for body- and gaze-orienting responses. Its superficial layer is, next to the lateral geniculate nucleus, the second major target of retinal ganglion axons and is retinotopically organized. Here we show that in the mouse there is also a precise organization of orientation preference. In columns perpendicular to the tectal surface, neurons respond to the same visual location and prefer gratings of the same orientation. Calcium imaging and extracellular recording revealed that the preferred grating varies with retinotopic location, and is oriented parallel to the concentric circle around the centre of vision through the receptive field. This implies that not all orientations are equally represented across the visual field. This makes the superior colliculus different from visual cortex and unsuitable for translation-invariant object recognition and suggests that visual stimuli might have different behavioural consequences depending on their retinotopic location. 1 Netherlands Institute for Neuroscience, an institute of the Royal Academy of Arts and Sciences, Cortical Structure & Function group, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands. Correspondence and requests for materials should be addressed to J.A.H. (email: [email protected]). NATURE COMMUNICATIONS | 6:6773 | DOI: 10.1038/ncomms7773 | www.nature.com/naturecommunications 1 & 2015 Macmillan Publishers Limited. All rights reserved. ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/ncomms7773 ells in the primary visual cortex (V1) respond optimally to single and multi-units recorded at different depths preferred the edges or lines of a particular orientation. -
Orienting Head Movements Resulting from Electrical Microstimulation of the Brainstem Tegmentum in the Barn Owl
The Journal of Neuroscience, January 1993, 13(l): 351370 Orienting Head Movements Resulting from Electrical Microstimulation of the Brainstem Tegmentum in the Barn Owl Tom Masino and Eric I. Knudsen Department of Neurobiology, Stanford University, Stanford, California 943055401 The size and direction of orienting movements are repre- movement latency, duration, velocity, and size each dem- sented systematically as a motor map in the optic tectum of onstrated dependencies on stimulus amplitude, frequency, the barn owl (du Lac and Knudsen, 1990). The optic tectum and duration. projects to several distinct regions in the medial brainstem The data demonstrate directly that at the level of the mid- tegmentum, which in turn project to the spinal cord (Masino brain tegmentum there exists a three-dimensional Cartesian and Knudsen, 1992). This study explores the hypothesis that representation of head-orienting movements such that hor- a fundamental transformation in the neural representation izontal, vertical, and roll components of movement are en- of orienting movements takes place in the brainstem teg- coded by anatomically distinct neural circuits. The data sug- mentum. Head movements evoked by electrical microstim- gest that in the projection from the optic tectum to these ulation in the brainstem tegmentum of the alert barn owl were medial tegmental regions, the topographic code for orienting cataloged and the sites of stimulation were reconstructed movement that originates in the tectum is transformed into histologically. Movements elicited from the brainstem teg- this Cartesian code. mentum were categorized into one of six different classes: [Key words: optic tectum, superior colliculus, saccadic saccadic head rotations, head translations, facial move- head movement, brainstem tegmentum, interstitial nucleus ments, vocalizations, limb movements, and twitches. -
Brainstem Dysfunction in Critically Ill Patients
Benghanem et al. Critical Care (2020) 24:5 https://doi.org/10.1186/s13054-019-2718-9 REVIEW Open Access Brainstem dysfunction in critically ill patients Sarah Benghanem1,2 , Aurélien Mazeraud3,4, Eric Azabou5, Vibol Chhor6, Cassia Righy Shinotsuka7,8, Jan Claassen9, Benjamin Rohaut1,9,10† and Tarek Sharshar3,4*† Abstract The brainstem conveys sensory and motor inputs between the spinal cord and the brain, and contains nuclei of the cranial nerves. It controls the sleep-wake cycle and vital functions via the ascending reticular activating system and the autonomic nuclei, respectively. Brainstem dysfunction may lead to sensory and motor deficits, cranial nerve palsies, impairment of consciousness, dysautonomia, and respiratory failure. The brainstem is prone to various primary and secondary insults, resulting in acute or chronic dysfunction. Of particular importance for characterizing brainstem dysfunction and identifying the underlying etiology are a detailed clinical examination, MRI, neurophysiologic tests such as brainstem auditory evoked potentials, and an analysis of the cerebrospinal fluid. Detection of brainstem dysfunction is challenging but of utmost importance in comatose and deeply sedated patients both to guide therapy and to support outcome prediction. In the present review, we summarize the neuroanatomy, clinical syndromes, and diagnostic techniques of critical illness-associated brainstem dysfunction for the critical care setting. Keywords: Brainstem dysfunction, Brain injured patients, Intensive care unit, Sedation, Brainstem -
Isolated Necrosis of Central Tegmental Tracts Due to Neonatal Hypoxic-Ischemic Encephalopathy: MRI Findings
Journal of Neurology & Stroke Case Report Open Access Isolated necrosis of central tegmental tracts due to neonatal hypoxic-ischemic encephalopathy: MRI findings Abstract Volume 11 Issue 1 - 2021 Perinatal hypoxia is an old entity that still prevails today and may lead to neurological Tomás de Andrade Lourenção Freddi, Luiz sequelae that can go unnoticed until a certain age, generating many costs for public health. In this case report, we demonstrate on magnetic resonance imaging an unusual pattern of Fellipe Curvêlo Ciraulo Santos, Nelson Paes perinatal hypoxia in a preterm 5-month-old infant, involving the central tegmental tracts Fortes Diniz Ferreira, Felipe Diego Gomes and briefly discuss its possible pathophysiology. Dantas Department of Radiology, Hospital do Coração, Brazil Keywords: magnetic resonance imaging, asphyxia, hypoxic-ischemic encephalopathy, tegmentum, neonates, brainstem Correspondence: Tomás de Andrade Lourenção Freddi, Hospital do Coração, 147 Desembargador Eliseu Guilherme Street, São Paulo, SP, 04004-030, Brazil, Tel +5511976059280, Email Received: May 25, 2020 | Published: Febrauary 15, 2021 Abbreviations: MRI, magnetic resonance imaging; HII, that connect the red nucleus and the inferior olivary nucleus, being hypoxic-ischemic injury; FLAIR, fluid-attenuated inversion recovery; part of the dentato-rubro-olivary system, called Guillain–Mollaret CTT, central tegmental tract; VGB, vigabatrin triangle.3–5 Introduction Hypoxic-ischemic injury (HII) is one of the most important causes of encephalopathy in neonates, irrespective of gestational age, and may occur in the uterus or during delivery by different intrapartum conditions. In preterm or very low birth weight infants, brain magnetic resonance imaging (MRI) can demonstrate multiple different findings, which a detailed description is beyond the scope of this article, although being periventricular leukomalacia the most frequent (seen in at least 50% of cases). -
SAY: Welcome to Module 1: Anatomy & Physiology of the Brain. This
12/19/2018 11:00 AM FOUNDATIONAL LEARNING SYSTEM 092892-181219 © Johnson & Johnson Servicesv Inc. 2018 All rights reserved. 1 SAY: Welcome to Module 1: Anatomy & Physiology of the Brain. This module will strengthen your understanding of basic neuroanatomy, neurovasculature, and functional roles of specific brain regions. 1 12/19/2018 11:00 AM Lesson 1: Introduction to the Brain The brain is a dense organ with various functional units. Understanding the anatomy of the brain can be aided by looking at it from different organizational layers. In this lesson, we’ll discuss the principle brain regions, layers of the brain, and lobes of the brain, as well as common terms used to orient neuroanatomical discussions. 2 SAY: The brain is a dense organ with various functional units. Understanding the anatomy of the brain can be aided by looking at it from different organizational layers. (Purves 2012/p717/para1) In this lesson, we’ll explore these organizational layers by discussing the principle brain regions, layers of the brain, and lobes of the brain. We’ll also discuss the terms used by scientists and healthcare providers to orient neuroanatomical discussions. 2 12/19/2018 11:00 AM Lesson 1: Learning Objectives • Define terms used to specify neuroanatomical locations • Recall the 4 principle regions of the brain • Identify the 3 layers of the brain and their relative location • Match each of the 4 lobes of the brain with their respective functions 3 SAY: Please take a moment to review the learning objectives for this lesson. 3 12/19/2018 11:00 AM Directional Terms Used in Anatomy 4 SAY: Specific directional terms are used when specifying the location of a structure or area of the brain. -
Functional Organization of Cerebral Cortex
Functional Organization of Cerebral Cortex Systems Neuroscience University of Texas Health Sci. Center Graduate School of Biomedical Sciences 2019 Daniel J. Felleman, Ph.D. 7.168 [email protected] Outline Concepts underlying the subdivision of cortex Architectonics Topography: vision, audition, somatic sensation Cortical connections: hierarchical and parallel ‘streams’ Cortical Modules Specializations? Color Faces Objects/Places Actions Attention From monkeys to humans: what do we now know about brain homologies? Martin I Sereno , Roger BH Tootell Figure 2 Folded (left column) and unfolded (right column) reconstructions of the left cerebral cortex of a human, common chimpanzee, and macaque monkey are shown at the same scale. The cortical surface was Current Opinion in Neurobiology Volume 15, Issue 2 2005 135 - 144 http://dx.doi.org/10.1016/j.conb.2005.03.014reconstructed from T1-weighted MRI Global architectonics Principles of cortical lamination How is cortex subdivided? • Architectonics: cyto-, myelo-, chemo-, immuno-, etc. • Topography: retinotopy, somatotopy, tonotopy, movements, etc. • Connections: anterograde and retrograde tracers; cortical streams and hierarchical organization • Functional properties of neurons: single cells, circuits, modules, areas • Functional contributions to behavior: natural and experimental lesions Human Architectonics: Brodmann and von Bonin Nissl Myelin Pigment Architectonics continued: Immuno-labeled neuron types Smi32 is an antibody against a non-phosphorylated neurofilament. CAT301 is an antibody against cat spinal cord that labels large neuron types; specifically magnocellular-dominated pathways in monkeys and man. smi32 CAT301 Area V2 thick stripes Architectonics alone is usually insufficient… Quantitative Architectonics Macaque cortical areas identified by architecture after Felleman and Van Essen Lewis and Van Essen Some of the proposed cortical areas of primates shown on a dorsolateral view of the left cerebral hemisphere. -
Chapter 128: Basic Mechanisms of Sleep: New Evidence On
128 BASIC MECHANISMS OF SLEEP: NEW EVIDENCE ON THE NEUROANATOMY AND NEUROMODULATION OF THE NREM-REM CYCLE EDWARD F. PACE-SCHOTT J. ALLAN HOBSON The 1990s brought a wealth of new detail to our knowledge NREM sleep (noradrenergic, serotonergic, and cholinergic of the brain structures involved in the control of sleep and systems damped), and REM sleep (noradrenergic and sero- waking and in the cellular level mechanisms that orchestrate tonergic systems off, cholinergic system undamped) (1–4). the sleep cycle through neuromodulation. This chapter pre- sents these new findings in the context of the general history Original Reciprocal Interaction Model: An of research on the brainstem neuromodulatory systems and Aminergic-Cholinergic Interplay the more specific organization of those systems in the con- trol of the alternation of wake, non–rapid eye movement The model of reciprocal interaction (5) provided a theoretic (NREM), and REM sleep. framework for experimental interventions at the cellular and Although the main focus of the chapter is on the our molecular level that has vindicated the notion that waking own model of reciprocal aminergic-cholinergic interaction, and REM sleep are at opposite ends of an aminergically we review new data suggesting the involvement of many dominant to cholinergically dominant neuromodulatory more chemically specific neuronal groups than can be ac- continuum, with NREM sleep holding an intermediate po- commodated by that model. We also extend our purview to sition (Fig. 128.1). The reciprocal interaction hypothesis the way in which the brainstem interacts with the forebrain. (5) provided a description of the aminergic-cholinergic in- These considerations inform not only sleep-cycle control terplay at the synaptic level and a mathematic analysis of per se, but also the way that circadian and ultradian rhythms the dynamics of the neurobiological control system.