1. Introduction: Traumatic Brain Injury
Chris Rorden
Overview of course
Motivation and Significance of Topic
Basic terms and anatomy
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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 involved
Damage 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.

3. Regeneration
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 ~1908

4. Plasticity
The 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.

5. Types of Injury Focal 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).

6. TBI classification remains vague. Mild injuries much more common.
Severe
Moderate
Mild

7. GCS: Glasgow Coma Scale PTA: Post traumatic Amnesia
Classification
GCS: Glasgow Coma Scale
PTA: Post traumatic Amnesia
LOC: Loss of consciousness
Mild TBI Terms
Complicated mTBI: injury visible in brain scan
Postconcussion injury: long term deficits
Concussion: mTBI ~ brain clearly injured, typically full functional recovery. Permanent injury debated

8. Immediate and long term effects of TBI
Contusion (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.

9. TBI and age
TBI most common in young and old.
Classic ‘Bathtub’ function.
Children run into things, do not attend well
Adolescents drive cars and are often addled by testosterone.
Older individuals often fall.

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.
Images by Chris Rorden

11. Ambiguous Coordinates
Rat
Human brain rotated relative to spine
Ambiguous dimenstions
Dorsal/ventral
Rostral/caudal
Unambiguous dimensions
Head/Foot
Superior/Inferior
Anterior/Posterior R C V D
Human
Images by Chris Rorden V D V

12. Anatomy – Common Terms coronal sagittal axial
lateral < medial > lateral
Posterior <> Anterior
Inferior <> Superior
Posterior <> Anterior
Images by Chris Rorden
axial
Radiological convention: Left on right side
Neurological convention: Left on left side

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.
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Brain image by Chris Rorden

14. Coordinates - Talairach
Anterior Commissure (AC) is the origin for neuroscience.
We measure distance from AC
57x-67x0 means ‘right posterior middle’.
Three values: left-right, posterior-anterior, ventral-dorsal
Images by Chris Rorden

15. Recognizing the cortical lobes
Cortical lobes: Frontal, Parietal, Occipital Temporal, Insula.
N.B. Cerebellum and subcortical gray matter.
Images by Chris Rorden

16. The major sulci
Postcentral easy to find: becomes intraparietal. Precentral easy to find- attached to superior frontal. Between these is the Central (Rolandic).
Images by Chris Rorden
Sylvian (lateral) fissure
Interhemispheric fissure

17. Major sulci
You can usually find the central suclus’ motor hand area (omega shape on axial slice)
Images by Chris Rorden

18. Gyri and sulci
Naming of most gyri (ridges) and sulci (valleys) follows simple pattern of position (superior, middle, inferior) and lobe name.
Images by Chris Rorden