Biopsychology

• Nervous system


  Consists of CNS and PNS, collects, processes and responds to info from the environment, coordinates functioning of organs and cells
• CNS


  Central nervous system, brain and spinal cord
• Spinal cord


  Extension of the brain, responsible for reflex actions
• PNS


  Peripheral nervous system, sends info from CNS to muscles and glands
• Subdivisions of PNS


  • ANS (autonomic nervous system)
  • SNS (somatic nervous system)
• ANS


  Governs vital, automatic processes in the body (e.g. breathing, heart rate, digestion, sexual arousal, stress)
• Branches of ANS


  • Parasympathetic nervous system
  • Sympathetic nervous system
• SNS


  Controls muscle movement, receives info from sensory receptors
• Endocrine system


  Works alongside nervous system, releases hormones that have slower but powerful effects
• Hormones


  Chemicals secreted into the bloodstream that affect target organs
• Thyroid gland


  Produces hormone thyroxine, increases heart rate and affects cells in the body increasing metabolic rate and growth rate
• Pituitary gland


  Controls release of hormones from all other endocrine glands in the body
• Stress response


  Stress triggers hypothalamus, activates sympathetic branch of ANS, changes from resting parasympathetic state to physiologically aroused sympathetic state, releases adrenaline from adrenal medulla, increases heart rate and produces physiological arousal for fight/flight, parasympathetic nervous system returns body to rest once threat is gone
• Gland


  Organ that synthesises hormones
• Neurons


  Nerve cells that process and transmit messages through electrical/chemical signals
• Types of neurons


  • Motor neurons
  • Sensory neurons
  • Relay neurons
• Structure of a neuron

  • Biology
  • Electric transmission - firing a neuron
• Suggests theory of localisation of function - specific areas of brain associated with particular functions
• 19th century Paul Broca and Karl Wernicke discovered localisation
• Scientists generally believed holistic theory that the brain works as a whole
• Broca and Wernicke argued the brain is localised - different parts of the brain execute different tasks
• If a certain area becomes damaged, the function associated with that area is too
• Hemispheres of the brain

  Brain divided into symmetrical hemispheres, physiological functions dominated by a part - hemispheric lateralisation
• Cerebral cortex


  Outer 3mm thick layer of left and right hemisphere, grey matter
• Cortical areas


  • Motor area
  • Somatosensory area
  • Visual cortex
  • Auditory area
• Motor area


  Back of frontal lobe, controls voluntary movements in opposite side of the body
• Somatosensory area


  Front of parietal lobes, interprets sensory info from the skin (e.g. heat, touch, pressure)
• Visual cortex


  Back of brain occipital lobe, each eye sends info from right/left visual cortex, interpreted by left/right hemisphere
• Auditory area


  Temporal lobe, analyses speech-based info
• Broca's area


  Left frontal lobe, responsible for speech production
• Wernicke's area


  Left temporal lobe, responsible for language comprehension
• Damage to Broca's area causes Broca's aphasia - slow, laborious speech lacking in fluency
• Damage to Wernicke's area causes Wernicke's aphasia - fluent but meaningless speech
• Evidence for localisation


  • Brain scans
  • Neurosurgical evidence
  • Case study of Phineas Gage
• Brain scans have demonstrated specific areas of the brain being active during particular tasks
• Neurosurgical procedures have shown that removing certain brain areas can control aspects of behaviour
• The case of Phineas Gage suggests the frontal lobe may have a role in regulating mood
• Lashley's research suggested higher cognitive functions are not localised, but distributed in a holistic way
• Plasticity


  Brain's ability to compensate for damage or loss of function by other regions taking over that function - brain reorganises itself
• Plasticity allows for functional recovery of the brain after trauma