brain structure

• Phineas gage suffered a brain injury in 1848
• an iron rod when through Phineas gages face and through the top of his head damaging his prefrontal cortex
• Phineas gages personality had a fundamental change he went from being a reliable person to someone who was irresponsible, profound and aggressive
• case studies of people who had suffered brain damage allowed physicians to begin to map the brain
• the prefrontal cortex is associated with personality and decision making and is the front area of the brain just behind the forehead
• Roger Sperry (1970s)


  tested humans with their corpus callosum severed as treatment for epilepsy, a seizure disorder. He found that the hemispheres in human brains had different functions. The left hemisphere interpreted language but not the right hemisphere
• broca's area is located in the frontal lobe and is responsible for speech production
• Paul Broca had a patient known as 'tan' through which he discovered the area of tans brain the had been damaged was responsible for motor control involved in speech production
• Broca's area location

  lower part of the left frontal lobe
• Broca's areas function

  motor control involved in speech production
• Wernicke's area location

  rear of the left temporal lobe as it joins to the parietal lobe

  
• Wernicke's area function

  understanding of speech
• the midbrain contains an area called the periaqueductal grey matter (PAG) which links the amygdala and the hippocampus with the prefrontal cortex
• the midbrain has a role in coordinating and integrating behavioral responses to perceived internal and external stressors such as pain or threat
• Lonstein and Stern (1998)


  lesions to the PAG in rats that have recently given birth show an increase in aggression when the rats are confronted with potential threat in the form of unfamiliar male rats being put in the cage
• the amygdala is the center for emotions, emotional behavior and motivation
• the amygdala integrates internal and external stimuli and every sensory modality has an input, which when combined gives us an instinctive feeling or reaction to the environment that will include aggression
• the prefrontal cortex connects to the amygdala which may be the cause for the expression aggression
• the hypothalamus maintains homeostasis through the regulation of hormones including hormones that regulate sexual function. this is linked to aggressive behaviour in males through the production of testosterone
• lesions

  damage to the brain causing the area to die
• medial


  middle
• dorsal


  back
• lateral

  side
• homeostasis

  process that maintains the stability of the human body in response to changes in external conditions like temperature
• hormones are chemicals produced by glands that are used to signal between organs and tissues
• testosterone is the is principle male sex hormone and an anabolic steroid
• periaqueductal grey matter (PAG)


  are of grey matter in the midbrain that plays a role in the modulation of pain and in defensive behaviour
• prefrontal cortex location

  right behind the forehead

  
• prefrontal cortex function

  it is influential in governing social interaction and regulation of behaviour
• damage to the prefrontal cortex often leads to problems with anger management, irritability and impulse control