Chris Rorden Overview of course Motivation and Significance of Topic Basic terms and anatomy 2 Brain function Brain functions are both distributed and modular Modular focal injury can lead to specific impairment ID: 570764
Download Presentation The PPT/PDF document "1 Introduction: Traumatic Brain Injury" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
1
Introduction: Traumatic Brain Injury
Chris Rorden
Overview of course
Motivation and Significance of Topic
Basic terms and anatomySlide2
2
Brain function
Brain functions are both distributed and modular. Modular: focal injury can lead to specific impairment. E.G. Lanugage deficits typically seen after left but not right hemisphere injury.Distributed: large network involvedDamage to any nodes or white matter tracts lead to eye movement deficits.Knock on effects: damage to one node degrades performance upstream.Damage to V1 effectively disables V2. Disconnection syndromes:Damage to white matter sufficient to disable intact cortex. Slide3
Regeneration
3
Peripheral nervous system can exhibit profound rehabilitation.
In general, CNS neurons do not regenerate, though glial cells often do.
Neurons can exhibit dendritic sprouting.
Changes in neurotransmitters and blood flow also play a role.
Rivers and Head ~1908Slide4
PlasticityThe brain is often able to compensate in response to small injuries.Most rehabilitation aims to leverage this.Plasticity effects are age related, typically younger individuals show better effects.Plasticity also changes with time. Injury and recovery often exhibits a characteristic time course.Plasticity is typically a good thing, but not always.
4Slide5
Types of InjuryFocal versus Diffuse.Focal refers to discrete spatial extent, for example TBI due to mechanical force (vulnerable regions) or stroke due to blockage (ischemic).Diffuse refers to widespread injury to many regions. For example TBI due shearing of white matter or stroke due to bleeding (hemorrhagic).
5Slide6
TBITBI classification remains vague.Mild injuries much more common.
6Slide7
ClassificationGCS: Glasgow Coma ScalePTA: Post traumatic AmnesiaLOC: Loss of consciousnessMild TBI TermsComplicated mTBI: injury visible in brain scanPostconcussion injury: long term deficitsConcussion: mTBI ~ brain clearly injured, typically full functional recovery. Permanent injury debated
7Slide8
Immediate and long term effects of TBIContusion (bruising) results in increased cranial pressure. Brain can herniate. Life or death situation.TBI also associated with latent effects. Often symptoms get worse with time.Epilepsy (recurrent seizures) can begin months after injury.
8Slide9
TBI and ageTBI most common in young and old.Classic ‘Bathtub’ function. Children run into things, do not attend wellAdolescents drive cars and are often addled by testosterone.Older individuals often fall.
9Slide10
10
Reporting findings
How do we describe anatomy to others?We could use anatomical names, but often hard to identify.We could use Brodmann’s Areas, but this requires histology – not suitable for invivo research.Both show large between-subject variability.Requires anatomical coordinate system.Slide11
11
Ambiguous Coordinates
Human brain rotated relative to spineAmbiguous dimenstionsDorsal/ventralRostral/caudalUnambiguous dimensionsHead/FootSuperior/InferiorAnterior/Posterior
R
C
R
C
R
C
V
D
V
D
V
D
Rat
HumanSlide12
12
Anatomy – Common Terms
Posterior
<>
Anterior
Posterior
<>
Anterior
Inferior
<>
Superior
lateral <
medial
> lateral
Radiological convention: Left on right side
Neurological convention: Left on left side
sagittal
coronal
axialSlide13
13
Brain Coordinates
On Earth: North, South, East and West.0˚N/S explicitly defined by spheres rotation (equator). 0˚E/W arbitrary (Greenwich by convention).For brain: Left/Right, Sup./Inf., Ant./Post.Origin of L/R explicitly defined (brain symmetry)Origin of S/I and A/P arbitrary.Slide14
14
Coordinates -
TalairachAnterior Commissure (AC) is the origin for neuroscience.We measure distance from AC57x-67x0 means ‘right posterior middle’.Three values: left-right, posterior-anterior, ventral-dorsalSlide15
15
Recognizing the cortical lobes
Cortical lobes: Frontal, Parietal, Occipital Temporal, Insula.N.B. Cerebellum and subcortical gray matter.Slide16
16
The major sulci
Postcentral
easy to find: becomes
intraparietal
.
Precentral
easy to find- attached to
superior frontal
. Between these is the
Central (Rolandic)
.
Interhemispheric fissure
Sylvian (lateral) fissureSlide17
17
Major sulci
You can usually find the central suclus’ motor hand area (omega shape on axial slice)Slide18
18
Gyri and sulci
Naming of most gyri (ridges) and sulci (valleys) follows simple pattern of position (superior, middle, inferior) and lobe name.