The Brain and Behavior: The Basics

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The Brain and BehaviorThe Basics
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Main Brain Functions

• There are FIVE MAIN brain functions
• Sensation
• Motion / Movement
• Reproduction
• Internal Regulation
• Thought / Cognition
• Most important for crime?

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Which part?

• Which part of brain is responsible for such
  executive cognitive functions?

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Brain Structure and Process

• Brain can be divided into Cortex and Subcortex
• Cerebrum -- largest portion of cortex -- wrinkled
  mass in 2 hemispheres
• Divided into FOUR LOBES

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Brain Structure and Process

• Frontal lobe thought, intellect, associations,
  planning, intent, inhibition/self control
• Parietal lobe works with frontal lobe,
  sensation
• Occipital lobe vision, abstract concepts
• Temporal lobe hearing, learning/memory,
  autonomic response, regulation of hormones,
  emotion, aggression

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Obviously then

• The parts most important for criminal behavior
  are frontal lobes and temporal lobes

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We know the brain

• Controls behaviors, including crime, through
• Learning (i.e., association)
• Emotion (e.g., anger, sadness, vengeance)
• Lack of self-control (i.e., inability to control
  urges)
• Brain chemistry (i.e., neurotransmitter and
  enzyme levels)
• Abnormal influences (e.g., brain dysfunction and
  injury)

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Neurotransmitters

• Neurons are nerve cells in brain (100 bil.)
• Transmit info. from cell to cell through
  electrical impulse
• over trillions of connections (synapses)
• Impulse causes release of neurotransmitters
  (naturally occurring brain chemicals)
• Released into synapse of neuron and
• received by other neurons (or not)
• Stimulate or inhibit brain function

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Neurotransmitters

• Levels affected by genes and environmental
  factors
• (such as social status, diet, drugs, stress,
  toxins)
• Those related to aggression include
• Serotonin (low levels)
• Norepinephrine (low levels)
• Dopamine (high levels)

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Enzymes

• Enzymes are substances in the brain that
• Build neurotransmitters from foods we eat
• and break them down
• For example, monoamine oxidase (MAO)
• metabolizes serotonin, dopamine, norepinephrine
  
• Low levels of MAO found in antisocial populations

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Brain dysfunction

• Means some interference with normal brain
  function
• Can occur in the womb
• For example, alcohol, cigarettes, illicit drugs,
  poor diet, stress, toxins
• Occurs regularly in youth and adults
• 2.5 6.5 million traumatic brain injuries (TBI)
  each year
• 300,000 to hospital 70,000-90,000 long-term
  brain dysfunction

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Brain dysfunction

• Causes include
• Accidents, falls
• Violence victimization
• Sport injuries
• (head injuries)
• Most common in young males (15-24 years old)
• 15,000 children suffer TBI each year

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Brain dysfunction

• Outcomes include
• Language / cognition problems
• Learning / school problems
• Emotional problems
• Relationship problems
• School / work problems

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Brain dysfunction

• Outcomes include
• Difficulty solving problems
• Difficulty planning for future
• Difficulty organizing
• Difficulty controlling violent impulses
• Crime, suicide, divorce, unemployment, substance
  abuse