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