BIO ASSUMPTIONS

• Neurotransmitters

  Chemical messengers that pass signals across neurons
• Neurotransmitter signaling

  1. Neurotransmitters bind to receptor sites on dendrites

  2. Sends a signal from cell body to axon hillock

  3. Axon terminal releases neurotransmitters into synapse

  4. Neurotransmitters bind to receptor sites of postsynaptic neuron
• Dendrites

  Finger-like structures surrounding a cell body with a nucleus
• Axon

  Long extension reaching an axon terminal
• Synapse

  Gap where neurotransmitters are released
• Postsynaptic neuron

  Neuron that receives the neurotransmitter signal
• Neurotransmitters reach postsynaptic neuron

  Neurotransmitter binds to receptor sites, changing chemical signal to electrical
• Neurotransmitters

  Chemical messengers that pass signals from the presynaptic neuron to the postsynaptic neuron across the synapse
• Neurotransmitters can be linked to schizophrenia

  Dopamine levels have been linked to positive and negative symptoms of schizophrenia
• Dopamine

  Controls bodily movements and emotional responses, affects mood, sleep, memory and learning
• Imbalances in Dopamine (too much)


  Have been linked to schizophrenia
• Two major dopamine pathways linked to positive and negative symptoms of schizophrenia

  1. Mesolimbic pathway (ventral tegmental area to nucleus accumbens)

  2. Mesocortical pathway (ventral tegmental area to frontal lobe)
• Mesolimbic pathway

  Fires too much dopamine too quickly, linked to positive symptoms of schizophrenia (delusions and hallucinations)
• Mesocortical pathway

  Has too little dopamine transmission, linked to negative symptoms of schizophrenia (alogia, apathy and catatonia)
• Localisation of brain function

  Certain areas of the brain are responsible for different functions
• Cerebral cortex

  • Divided into four lobes
• Frontal lobe

  • Located at the front of the brain
  • Involves thinking and creativity
  • Linked to our personalities
  • Responsible for problem-solving, decision making and motor skills
  • Damage can lead to changes in sexual habits, socialisation, attention, and increased risk-taking
• Parietal lobe

  • Found behind the frontal lobes, above the temporal lobes, at the top back of the brain
  • Responsible for sensory processes such as pain, touch, and the ability to feel temperature
  • Damage to the left parietal lobe can result in "Gerstmann's Syndrome" - right-left confusion and difficulty with writing and mathematics
• Temporal lobes

  • Found on either side of the brain and just above the ears
  • Responsible for auditory information such as interpreting sounds and hearing different languages
  • Damage can lead to problems with memory and language skills
• Occipital lobe

  • Found in the bottom back of the brain
  • Responsible for interpreting visual stimuli and information such as identifying colours and recognising words
  • Damage can cause visual problems, such as difficulty recognising objects, an inability to identify colours and trouble recognising words
• Localisation of brain function

  Certain areas of the brain are responsible for different functions
• Cerebral cortex

  • Divided into four lobes: frontal, parietal, occipital and temporal lobes
• Damage to prefrontal cortex

  Can result in impulsivity, loss of self-control, immaturity, and the inability to modify behaviour
• Damage to prefrontal cortex

  Could in turn cause aggressive behaviour
• Limbic system


  • Amygdala, hippocampus, and prefrontal cortex govern emotional expression
• Lower activity in limbic system areas in murderers


  Possibly causing abnormal emotional responses
• Corpus callosum


  Responsible for the transfer of information between the two hemispheres
• Right side of the brain

  Involved in the generation of negative emotions
• Left hemisphere

  Controls and inhibits negative emotions
• Malfunctioning corpus callosum


  Negative emotions generated by the right side of the brain may not be regulated by the left side, leading to violent, uninhibited behaviour
• This assumption can be applied to the violent behaviour of murderers, as found by Raine et al.'s study Brain Abnormalities in Murderers Indicated by PET Scans
• Murderers showed less activity in the prefrontal cortex
• Darwin's theory of natural selection

  Those who adapt to their environment tend to survive and reproduce, whereas those who do not adapt will not survive or reproduce
• Evolutionary psychologists

  • Individual differences in members of a species are due to differences in their genes
  • Those with characteristics most suited to the environment in which they live are more likely to have evolved
• Genes that allow individuals to be successful


  Are passed to their offspring who will, in turn, also be more successful because they innately can survive and evolve too
• Theory of natural selection

  Altruism is an inherited, adaptive trait because saving an offspring (or other relative) enhances the survival of the individual's gene pool
• Darwin's theory of natural selection

  Those who adapt to their environment tend to survive and reproduce, whereas those who do not adapt will not survive or reproduce
• Genes that allow individuals to be successful

  Are passed to their offspring who will also be more successful because they innately can survive and evolve too
• Survival of the fittest


  Genes within evolved families are more likely to be passed to each new generation
• Male mate preferences

  • Look for females who are more fertile (young and healthy)
  • Use visual cues like smooth skin, glossy hair and thin waist (physical attractiveness)
  • Focus is on reproduction