Introduction: Traumatic Brain Injury Chris Rorden Overview of course Motivation and Significance of Topic Basic terms and anatomy Except where noted the content in this presentation was created by Chris Rorden. All of his work may be freely reused without individual permission according to the terms of this license. You do not need to obtain a specific statement of permission from the licensor (unless you wish to use the work under different terms than the license stated). Chris Rorden's work is distributed with the Creative Commons Attribution license (CC by http://creativecommons.org/licenses/by/3.0/). You are free to Share - to copy, distribute and transmit the work. And to Remix - to adapt the work. Under the following conditions. Attribution- You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). With the understanding that: Waiver - Any of the above conditions can be waived if you get permission from the copyright holder. Public Domain - Where the work or any of its elements is in the public domain under applicable law, that status is in no way affected by the license. Other Rights - In no way are any of the following rights affected by the license: Your fair dealing or fair use rights, or other applicable copyright exceptions and limitations; The author's moral rights; Rights other persons may have either in the work itself or in how the work is used, such as publicity or privacy rights. Specifically, Chris Rorden asks that you ensure that his images maintain attribution to him. For example, you couple put the text 'From Chris Rorden' beneath a picture or include the text "Images by Chris Rorden, distributed under the Creative Commons Attribution license (CC by http://creativecommons.org/licenses/by/3.0/)" in the notes field of your presentation.

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.

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

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.

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).

TBI classification remains vague. Mild injuries much more common. Severe Moderate Mild http://en.wikipedia.org/wiki/Traumatic_brain_injury

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

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.

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.

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

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

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

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. http://en.wikipedia.org/wiki/File:Longitude_(PSF).png ScottForesman grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law. Brain image by Chris Rorden

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

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

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

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

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