brain damage & neuroplasticity. etiology of brain damage traumatic brain injury (tbi)...
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Brain Damage & Neuroplasticity
Etiology of Brain Damage
• Traumatic Brain Injury (TBI)
• Cerebrovascular Injury (CVI)
• Tumors
• Anoxia (e.g., near drowning, drug overdose)
• Toxins (e.g., lead)
• Diseases (e.g., Herpes, encephalitis)
• Seizures
Traumatic Brain Injury
1. Open Head Injury (e.g., missile wound) –
focal damage and some diffuse damage
Classic Case: Phineas Gage
Phineas Gage: Frontal Lobe
Injury
Rosenzweig et al., 2002
Prefrontal Cortex:
Organizes cognitions,
emotions and behavior.
Blue – dorsolateral prefrontal
Green – orbitofrontal region
Rosenzweig et al., 2002
Prefrontal Cortex: Distinguishes Homo Sapiens from other mammals
Rosenzweig et al., 2002
Behavioral Disruption Following Prefrontal Lesions
(note: any type of brain damage can result in a Prefrontal Syndrome)
Rosenzweig et al., 2002
Traumatic Brain Injury (cont’d)2. Closed Head Injury
- concussion (mild brain injury)- moderate to severe brain injury: classification dependent on the degree of post-traumatic amnesia (or anterograde amnesia – deficits in new learning)- Pathophysiology of TBI
~ focal damage (coupe & contra-coupe) ~ diffuse damage (shearing & tearing of
axons referred to as diffuse axonal injury)
Functional Changes:
• Depends on where the focal damage is:– Frontal?
– Parietal?
– Occipital?
– Temporal?
– Limbic System?
– Basal Ganglia?
– Hypothalamus?
– Brainstem?
Identify behaviors associated with these
areas.
Focal damage can affect specific behaviors and
impact related behaviors.
Diffuse damage will cause widespread tissue loss.
Cerebrovascular Injury
• Stroke (Ischemia – loss or reduction of blood circulation)
Thrombosis (large blockage)
Transient Ischemic Attack (TIA)
What causes the brain damage? (next slide)
Stroke: Source of Injury and Treatment
Rosenzweig et al., 2002
Behavioral Disruption
following Right Hemisphere
Stroke: Hemispatial
Neglect
Rosenzweig et al., 2002
Other Causes of Brain Damage:• Tumors – these can be small to large cyst-like
tumors or sticky, tentacle-like tumors• Toxins – heavy metals such as lead cause damage.
Lead replaces the oxygen molecule, causing widespread damage (sources: lead paint, leaded gasoline fumes)
• Anoxia – loss of oxygen causes diffuse damage• Diseases – numerous…• Seizures – uncontrolled electrical activity cause
Glutamate Toxic Casacade (as occurs with stroke)
Did you know that…
• if you understand the functional organization of the brain in a healthy person, you will be able to understand functional changes following brain damage?
AND (if you understand this)
• you will be able to understand problems associated with psychiatric disorders?
Remember – There is always recovery due to Neuroplasticity
Rosenzweig et al., 2002