brain structure linking to aggression

• function of prefrontal cortex

  regulates behaviour and governs social interaction, can delay gratification of an impulse by inhibiting messages from amygdala
• what happens when PFC is damaged

  levels of inhibition if amygdala is reduced so levels of aggression increase
• evidence to support PFC has links to aggression

  Phineas Gage - had iron rod through head, after accident became more irresponsible and aggressive = due to damage to his PFC
• function of hypothalamus


  regulates responses to emotional circumstances and maintains homeostasis and the regulation of hormones
• what happens when hypothalamus is damaged

  results in inappropriate aggressive responses to perceived threat, releases more testosterone = higher aggression
• evidence to show hypothalamus is linked to aggression

  animal experiments = electrical stimulation of hypothalamus in cats causes sham rage, a very aggressive response
• function of amygdala


  center for emotions, behaviour and motivation, recognises threats and triggers basic aggressive responses to them
• what happens when the amygdala is damaged/removed

  makes animals more passive and less aggressive
• evidence for amygdala linking to aggression in humans

  charles whitmann - conducted a school shooting, killed his wife and mother, experiences feelings of rage, confusion and violent impulses = caused by a tumor he had pressing against his amygdala
• evidence for amygdala linking to aggression in research

  Swantje - found people with higher aggression had smaller amygdala volumes
• what happens when serotonin levels are decreased/underactive

  self control levels reduce = more impulsive behaviors and stimulates dopamine overactivity
• research showing decreased serotonin can lead to aggression

  levels of serotonin breakdown product were lower in violent impulsive offenders
• evaluation - evidence for brain structure linking aggression

  animal experiments - Flynn - showed stimulation of hypothalamus caused sham rage and extreme aggression

  CA = ethical issues and animals have a less developed cerebral cortex than humans so cant apply results to humans
• application of brain damage linking aggression

  in law - finding individuals NGRI = can help explain people aggression - however can be other factors that influenced their aggression
• strength 1


  scientific method used eg PET scans = objectivity = validity increases as no subjectivity in data

  CA = difficult to isolate brain areas so can't fully establish cause and effect between specific areas and certain behaviours
• strength 2


  explanation is reductionist = simple organic causation for aggression, not a complete explanation

  CA = needs to be reductionist as too difficult to do research into all behaviors and parts of brain that could impact aggression
• general - function of thalamus

  receives info from senses and passes it onto appropriate areas, acts as a gate to info and has a role on sleep and wakefulness
• general - function of cerebellum

  coordinates posture, balance, movement, receives and integrates info from spinal cord
• general - function of corpus collosum

  a dense collection of nerve cells, physically connect the two hemispheres and allows communication between them
• general - function of limbic system

  consists of amygdala and other structures, plays role in regulating emotional responses and in memory
• general - function of hypothalamus

  controls motivational behaviour, has a role in stress response, maintains balance of bodily functions/homeostasis
• general - function of frontal lobe

  controls high level cognitive functions eg thinking, problem solving, has motor cortex so controls voluntary movements
• general - function of parietal lobe

  processes sensory info from skin
• general - function of occipital lobe

  contains visual cortex so deals with visual info
• general - function of temporal lobe


  deals with sound info, processes location, volume and pitch of sounds, has a role in understanding language
• what are neurons


  nerve cells which carry messages as electrical or chemical signals
• function of a dendrite

  carry impulses from neighbouring neurons to body cells
• function of axon


  carry impulses down length of neuron
• function of myelin sheath

  fatty layer which covers the axon to protect it and speed up the transmission of electrical impulses
• function of terminal button

  where neurotransmitters are released
• what is role of sensory neurons

  carry messages from sensory receptors to CNS
• role of motor neurons

  carries messages from CNS to effectors
• role of relay neurons

  connect sensory and motor neurons
• how are messages within the neuron transmitted

  electrically
• how are messages between neurons transmitted

  chemically
• what is the process of action potential

  1 - at rest inside of neuron is negatively charged and outside is positive

  2 - when neuron is sufficiently activated by a stimulus the inside becomes positively charged for a split second = depolarisation

  3 - this creates an electrical impulse also called action potential
• what are neurons separated by

  a synaptic cleft/synapse
• process of synaptic transmission

  1 - process starts with an action potential - electrical impulse triggers the release of NTs from vesicles in the axon

  2 - NTs diffuse as chemicals across the synapse

  3 - they fit into matching receptor sites on the post synaptic neuron and they are converted back to electrical impulses

  4 - NTs remaining in the synapse are reabsorbed into pre synaptic neuron (reuptake) to be used again