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