Chapter 15 PSYB64
Soccer players perform worse on tests for attention, memory, and planning compared to swimmers and
o Sortland and Tysvaer (1989) using CT found that 1/3 of former Norwegian national soccer
members had cerebral atrophy.
o Most likely the source of injury is from “heading” the ball.
o It is reported that the greatest cognitive deficits occurred among players who headed the ball
Brain is protected by skull bones/meninges, cerebrospinal fluid (CSF), and blood-brain barrier. Damage
can occur due to interruptions in the blood supply and head injuries.
Cells in nervous system (NS) rely on oxygen which is supplied by rich network of blood vessels
o Circulation of blood to neural tissue can be ruptured/blocked and that can cause serious damage
Stroke – type of brain damage caused by an interruption of blood supply to the brain by bleeding or
blockage of blood vessel.
o Risk factors of stroke – age, hypertension, smoking, diabetes, high cholesterol, obesity, alcohol
use, cocaine, amphetamines, heroin, and other drugs
o Atherosclerosis also increases risk of stroke when arteries are narrowed/hardened
Cerebral hemorrhage (Bleeding in the brain)– Condition caused by bleeding in the brain.
o Generally results from hypertension (high blood pressure) or structural defects in arteries serving
o Sometimes occur due to rupture of aneurysms –balloon-like bulge in walls of arteries
o Can occur due to blood diseases such as leukemia or exposure to toxic chemicals.
o Usually fatal because of brain damage produced by blocking blood supply to neurons and
flooding areas of brain with salty blood that dehydrates and kills nearby neurons
Ischemia (low oxygen level) – Blockage of blood vessels result in ischemia. It is condition where
inadequate blood flow results in insufficient quantities of oxygen being delivered to tissue.
o Cases of Ischemia account for 80% of all strokes.
o Can result in neural tissue death in an area called infarct – can causes changes in consciousness,
sensation, ability to move (depends on their size and location)
o Transient ischemic attacks (TIAs) – produces brief (less than 24 hours) episode of stroke
symptoms that doesn’t cause permanent damage. They are strong predictors of subsequent
When an area of the brain is deprived of oxygen for a sufficient amount of time, cells begin to die. The
area of dead tissue is referred to as an infarct.
Material causing blockage of a blood vessel can be classified as either a thrombosis or an embolism.
Thrombosis –A plug of blood or other material that blocks a blood vessel without from its point of origin.
Embolism – A plug that passes into smaller and smaller blood vessels until it forms a blockage.
o Blockages in small blood vessels are less damaging than in large arteries serving the brain but
multiple small strokes can cause significant damage.
Cells in middle layers of cortex and hippocampus are most vulnerable to ischemia. It isn’t only lack of
oxygen that caused cell dead, there are other processes involved in brain damage caused by ischemia.
Excitotoxicity – coined by John Olney to describe ability of excess glutamate to kill neurons
o Now believe that cell death after a stroke is caused by excess glutamate activity triggered by lack
o Excess glutamate in neuron initiates cascade of events leading to cell death
o In response to unusual amounts of glutamate, abnormal calcium activity in the cell stimulates 4
‘executioner’ enzymes that damage cell’s energy stores, membranes, cytostructure, and DNA