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Neuroanatomy & NeuroplasticitySection 2

THE ESSENTIAL BRAIN INJURY

GUIDE

ContributorsErin D. Bigler, PhDMichael R. Hoane, PhDStephanie Kolakowsky-Hayner, PhD, CBIST, FACRMDorothy A. Kozlowski, PhDEric Spier, MD, BIM, CBISTina Trudel, PhD

Neuroanatomy and Neuroimaging

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Learning Objectives

Understand the anatomy of the brain, spine, and

spinal cord;

Compare the incidence of

spinal cord injury to TBI

Distinguish between symptom patternsdue to brain injury and syndromes inspinal cord injury

Articulate the methods of neuroimagingwhich support diagnostic and treatmentdecisions when a patient has sustainedeither a brain injury or spinal cord injury.

NEUROANATOMY

Skull Anatomy

The skull is a rounded layer of bone designed to protect the brain from penetrating injuries

The inside of the skull is rough with many bony protuberances

These ridges can result in injury to the brain during rapid acceleration

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Cerebrospinal Fluid3rd & 4th Ventricles

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Lateral Ventricles

3rd & 4th

Ventricles

Lateral Ventricles

The Meninges The meninges are layers

of tissue that separate the skull and the brain

There are 3 layers Pia Mater Arachnoid Dura Mater

Pia Mater Arachnoid Dura Mater

Essential TIP!

The Meninges P-A-D the Brain

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Subdural space

Subarachnoid space

Gray Matter White Matter

AXON

CellBody Dendrites

Dendritic Spines

AXONTerminals

Synapse

Brain Cells

NEURONS

Neuron B Neuron CNeuron A

Neurons Communicate via Synapses

AXONTERMINALsynaptic

vesicle

SYNAPTIC CLEFTneurotransmitters

receptor

DENDRITIC SPINE

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BRAIN STEM

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Brain Stem Anatomy

Midbrain Pons

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Medulla

Reticular Activating System

Arousal

Alertness

Concentration

Basic biological rhythms

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DIENCEPHALON

Thalamus and Hypothalamus16

LIMBIC SYSTEM

Limbic System18

Hippocampus Amygdala

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Basal Ganglia and CerebellumBasal Ganglia Cerebellum

THE CEREBRAL CORTEX

Two Hemispheres Four Lobes Interconnected

Information Processing

Holistic

Visual Spatial

Intuitive

Controls left side of body

Music, art, shapes

Linear

Verbal-analytic

Logical

Controls right side of body

Speaking, reading, writing

Right Hemisphere Left hemisphere

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Cerebral Features

• 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

GyriSulcus

Fissure

Frontal Lobe

Primary Motor CortexPrefrontal Cortex

Frontal Poles

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Frontal Lobe Functions Planning

Organizing

Problem Solving

Judgment

Impulse Control

Decision Making

Working Memory

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Temporal Lobe

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Expressive and Receptive SpeechBroca’s Area

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Wernicke’s Area

Occipital Lobe

Primary Visual Cortex

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Visual PathwayLeft Visual Field

Right Visual Field

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Parietal Lobe

Somatosensory Cortex

Primary Sensory Cortex

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SPINE AND SPINAL CORD

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Spinal Column Divisions

Cervical Spine showing Lateral, Anterior, and Posterior view

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Thoracic Vertebrae showing Lateral, Anterior, and Posterior views

Lumbar Vertebrae showing Lateral, Anterior, and Posterior views

Vertebral BodiesSpinal Cord

Meninges

Vertebra

Disk

Nerve Root

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Spinal Cord

Afferent Sensory Information

Efferent Signals

Spinal Cord

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Essential TIP! Afferent Nerves Ascend upward

Spinal Cord Syndromes

Central Cord Syndrome

Brown-Sequard Syndrome

Anterior Cord Syndrome

Posterior Cord Syndrome

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NEUROIMAGING

Computed Tomography (CT)

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Magnetic Resonance Imaging (MRI)37

Diffusion Tensor Imaging (DTI) Functional MRI (fMRI)

Brain Symmetry & Imaging38

MechanismsofTraumaticInjury

TRAUMATICIMPACTContactInjury

Headstruckbyoragainstanobject

TRAUMATICINERTIALNon‐ContactInjury

Brainmoveswithinskull

CLOSEDNon‐Penetrating

OPENPenetratingSkullFracture

MeningesBreach

Rotational/AngularForcesNon‐ContactInjury

Brainmoveswithinskull

FOCAL‐ OR‐

DIFFUSE

PRIMARILYDIFFUSEMULTIFOCAL

PRIMARILYFOCAL

BrainContusions

BrainLacerations

IntracerebralHemorrhage

DiffuseAxonalInjury

EpiduralHematomas

SubduralHematomas

IntracerebralHemorrhage

Infections

DiffuseAxonalInjury

WhiteMatterLesion

Hemorrhage

Categories of Brain Injury Focal Contusions

Lesions

Hematomas

Diffuse Diffuse Axonal Injury Hemorrhage

Mechanism of InjuryAcceleration-Deceleration (Traumatic Inertial)

http://www.calshipleymd.com/medical-animation/neurology-library/diffuse-axonal-injury-dai/

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Mechanism of Injury The bouncing of the

brain in the skull can result in injury in two sites

Coup Contrecoup

The initial site of injury (coup)

The contrecoup injury

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Mechanism of Injury: Intracranial Pressure

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Neuroprotection and Neuroplasticity

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Learning Objectives

Understand the conceptions of

neuroprotection, neuroplasticity, andneurodegeneration

Be able to explain factors leading to

neurodegeneration following TBI

Be able to articulate the

effects of braininjury and injury

severity

Be able to articulate the two main

areas of the brain known to be sites of

neurogenesis

Be able to distinguish betweenrehabilitative training models appropriate

for TBI and those for stroke

NEUROPLASTICITY

Early Research on NeuroplasticityThumb

D2 D3D4

D5

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Synaptogenesis

The greater the numbers of synapses within a grouping of neurons, the greater the speed and efficiency with which those neurons communicate

Definition: the formation of synapses between neurons

Dendritic spines have the ability to change in response

to experience

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Neuroplasticity Post-TBI

• Plasticity: the ability of the nervous system to change, grow or compensate for injury

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Neuroplasticity: TBI Research49

NEUROPROTECTION

Biological Cascade Following TBI Primary Injury - direct damage to the

brain Secondary Injury - causes additional

damage Excitotoxicity Edema Apoptosis

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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)

Human Studies Showing Efficacy (TBI)

Magnesium Increase Mg2 (decreased Mg2 results in excessive

production of free radical and mild inflammation)

Failed

Progesterone Decrease cerebral edema

Initial Efficacy; Follow Up Trial

Nicotinimide Reduce injury volume; decrease glial activation;

reduce BBB breaches; reduce edema

Unknown

?

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