THE ESSENTIAL BRAIN INJURY GUIDE

Transcription

1 THE ESSENTIAL BRAIN INJURY GUIDE Neuroanatomy & Neuroplasticity Section 2 Contributors Erin D. Bigler, PhD Michael R. Hoane, PhD Stephanie Kolakowsky-Hayner, PhD, CBIST, FACRM Dorothy A. Kozlowski, PhD Eric Spier, MD, BIM, CBIS Tina Trudel, PhD Learning Objectives Understand the anatomy of the brain, spine, and spinal cord; Distinguish between symptom patterns due to brain injury and syndromes in spinal cord injury Neuroanatomy and Neuroimaging Compare the incidence of spinal cord injury to TBI Articulate the methods of neuroimaging which support diagnostic and treatment decisions when a patient has sustained either a brain injury or spinal cord injury. 3 Skull Anatomy 6 The skull is a rounded layer of bone designed to protect the brain from penetrating injuries NEUROANATOMY The inside of the skull is rough with many bony protuberances These ridges can result in injury to the brain during rapid acceleration 1

2 Cerebrospinal Fluid 3 rd & 4 th Ventricles Lateral Ventricles Lateral Ventricles 7 The Meninges The meninges are layers of tissue that separate the skull and the brain Subdural space Subarachnoid space There are 3 layers Pia Mater Arachnoid Dura Mater 8 Essential TIP! 3 rd & 4 th Ventricles Gray Matter White Matter The Meninges P-A-D the Brain Pia Mater Arachnoid Dura Mater AXON AXON Terminals Brain Cells Neurons Communicate via Synapses Neuron A Neuron B Neuron C Cell Body Synapse Dendrites synaptic vesicle AXON TERMINAL neurotransmitters SYNAPTIC CLEFT NEURONS Dendritic Spines receptor DENDRITIC SPINE 11 BRAIN STEM 2

3 Brain Stem Anatomy 13 Reticular Activating System 14 Midbrain Pons Medulla Arousal Alertness Concentration Basic biological rhythms Thalamus and Hypothalamus 16 DIENCEPHALON Limbic System 18 Hippocampus Amygdala LIMBIC SYSTEM 3

4 Basal Ganglia and Cerebellum Basal Ganglia Cerebellum Two Hemispheres Four Lobes Interconnected THE CEREBRAL CORTEX Information Processing Right Hemisphere Left hemisphere 21 Cerebral Features Gyri Sulcus Holistic Visual Spatial Intuitive Controls left side of body Music, art, shapes Linear Verbal-analytic Logical Controls right side of body Speaking, reading, writing Gyri- Elevated ridges that wind around the brain Sulci- Small grooves dividing the gyri Fissures- Deep grooves, usually dividing large regions/lobes of the brain Fissure Prefrontal Cortex Primary Motor Cortex Frontal Lobe 23 Frontal Lobe Functions Planning 24 Frontal Poles Organizing Problem Solving Judgment Impulse Control Decision Making Working Memory 4

5 Temporal Lobe 25 Expressive and Receptive Speech Broca s Area Wernicke s Area 26 Occipital Lobe 27 Visual Pathway Left Visual Field 28 Right Visual Field Primary Visual Cortex Primary Sensory Cortex Somatosensory Cortex Parietal Lobe 29 SPINE AND SPINAL CORD 5

6 Spinal Column Divisions 31 Vertebral Bodies 32 Spinal Cord Disk Meninges Cervical Spine showing Lateral, Anterior, and Posterior view Nerve Root Vertebra Thoracic Vertebrae showing Lateral, Anterior, and Posterior views Lumbar Vertebrae showing Lateral, Anterior, and Posterior views Spinal Cord 33 Spinal Cord Syndromes 34 Afferent Sensory Information Spinal Cord Central Cord Syndrome Brown-Sequard Syndrome Anterior Cord Syndrome Efferent Signals Posterior Cord Syndrome Essential TIP! Afferent Nerves Ascend upward Computed Tomography (CT) NEUROIMAGING 6

7 Magnetic Resonance Imaging (MRI) 37 Brain Symmetry & Imaging 38 Diffusion Tensor Imaging (DTI) Functional MRI (fmri) Mechanisms of Traumatic Injury Categories of Brain Injury Focal Contusions TRAUMATIC IMPACT Contact Injury Head struck by or against an object OPEN CLOSED Penetrating Non Penetrating Skull Fracture Meninges Breach TRAUMATIC INERTIAL Non Contact Injury Brain moves within skull Rotational/Angular Forces Non Contact Injury Brain moves within skull Mechanism of Injury medical-animation/neurologylibrary/diffuse-axonal-injury-dai/ Acceleration-Deceleration (Traumatic Inertial) 40 Lesions Hematomas FOCAL OR DIFFUSE PRIMARILY FOCAL PRIMARILY DIFFUSE MULTIFOCAL Diffuse Diffuse Axonal Injury Hemorrhage Brain Contusions Brain Lacerations Intracerebral Hemorrhage Diffuse Axonal Injury Epidural Hematomas Subdural Hematomas Intracerebral Hemorrhage Infections Diffuse Axonal Injury White Matter Lesion Hemorrhage Mechanism of Injury Coup Contrecoup The bouncing of the brain in the skull can result in injury in two sites 41 Mechanism of Injury: Intracranial Pressure 42 The initial site of injury (coup) The contrecoup injury 7

8 Learning Objectives Be able to explain factors leading to neurodegeneration following TBI Be able to articulate the effects of brain injury and injury severity Neuroprotection and Neuroplasticity Understand the conceptions of neuroprotection, neuroplasticity, and neurodegeneration Be able to articulate the two main areas of the brain known to be sites of neurogenesis Be able to distinguish between rehabilitative training models appropriate for TBI and those for stroke 43 Early Research on Neuroplasticity 46 Thumb D2 D3 D4 D5 NEUROPLASTICITY Synaptogenesis Definition: the formation of synapses between neurons 47 Neuroplasticity Post-TBI The greater the numbers of synapses within a grouping of neurons, the greater the speed and efficiency with which those neurons communicate Dendritic spines have the ability to change in response to experience Plasticity: the ability of the nervous system to change, grow or compensate for injury 8

9 Neuroplasticity: TBI Research 49 NEUROPROTECTION Biological Cascade Following TBI Primary Injury - direct damage to the brain Secondary Injury - causes additional damage Excitotoxicity Edema Apoptosis 51 Potential Neuroprotective Agents for TBI Neuroprotective agents limit neuronal death following injury and/or enhance recovery Neuroprotective Agent Intervention Target Animal Models Showing Efficacy (Stroke) Magnesium Progesterone Nicotinimide Increase Mg2 (decreased Mg2 results in excessive production of free radical and mild inflammation) Decrease cerebral edema Reduce injury volume; decrease glial activation; reduce BBB breaches; reduce edema Human Studies Showing Efficacy (TBI) Failed? Initial Efficacy; Follow Up Trial Unknown 52 9