Unit 1 Psychology AOS 1: How does the brain function?

The role of mental processes and behaviour
1. Approaches over time to understanding the role of the brain, including phrenology, first brain experiments and neuroimaging techniques
  1. Development of psychology
    1. Phrenology - the relationship between features on the surface of a skull and a person’s characteristics.
      1. Franz Gall - different parts of brain have different functions
        localisation of brain function - the size of the area on the skull was how developed was also the amount of influence a characteristic is
        Spurzheim furthered his work by developed ‘faculties’. There were originally 27 but updated to 35.
        • Affective = Feelings (Destructiveness, hope, self-esteem) • Intellectual = Perceptive (Time, melody, language)
  2. Brain Experiments
    1. Electrical stimulation of the brain = initiate or inhibit activity in the brain using an electrode
      1. Penfield mapped the cortex, using epilepsy patients using this
    2. Brain ablation = disabling/destroying/removing selected brain tissue and assessing behavioural changes
      1. • Flourens removed small bits of cortex to observe recovery, understanding of a holistic view of the brain
      2. Lashley theories
        Lashley = a healthy part of cortex can take over function of damaged area
        Lashley = Mass action theory that large areas of brain that can function in complex functions
    3. Corpus callosum = a bundle of nerves that connects the left and right cerebral hemispheres and serves as the main communication pathway
    4. Hemispherical specialisation: Left controls language and logical thinking, right controls visual-spatial awareness
      1. Communicate through the corpus collosum to create a coordinated response
      2. Sperry and Gazzinga’s Split Brain Experiment
  3. Neuroimaging Techniques
    1. Structural = produces scans to look at the brain structure and anatomy
    2. Functional = analyse a function of the brain ‘at work’ and brain structure
2. The basic structure and function of the central and peripheral nervous systems and the body’s internal cells and organs
  1. Nervous system functions by receiving, processing and coordinating a response to information.
    1. CNS and PNS
      1. Central nervous system (CNS) consists of the brain and spinal cord.
      2. Peripheral nervous system (CNS) consists of the network of nerves outside CNS.
        Sympathetic and parasympathetic responses
        Sypathetic
        Pupils dilate, HR increase, Increase perspiration
        Parasympathetic
        Pupils contract, HR decrease, Decrease perspiration
3. The role of the neuron, and the role of glial cells in supporting neuronal function
  1. Neuron is an individual nerve cell. Specialised to receive, process and/or transmit messages.
    1. Sensory neurons located in the PNS and send sensory information to the CNS. They are specialized to respond to a stimulation
    2. Motor neurons carry messages from CNS to cells in skeletal muscles/organs/glands
    3. Interneurons are connecting neurons and are in the CNS only.
    4. Parts of the Neuron
      1. Dendrite receives information from a nearby neuron.
      2. Soma is the cell body which combines information from the dendrites and sends it to the axon.
      3. Axon transmits information from the soma towards axon terminal.
      4. Axon terminal hold and release neurotransmitters substance.
      5. Axon terminal hold and release neurotransmitters substance.
      6. Myelin is the white and fatty substance that insulates an axon increasing speed of neural transmissions
      7. Myelin sheath protects against interference from nearby neurons. It is not continuous and is separated by small gaps called nodes of Ranvier.
  2. Glial cells are specialised cells that are involved in insulation, nutrients, repair and eliminate waste in the nervous system.
  3. Synaptic transmissions
4. Structure and function of the brain
  1. Forebrain higher order thinking such as thinking, learning, memory, perception,
    1. Hypothalamus: maintains homeostasis and regulates pituitary gland (hormones)
    2. Thalamus: filters information from sense receptor sites (except the nose), and directs it to the appropriate lobes
    3. Cerebrum: made up of the four lobes
  2. Midbrain controls functions such as movement; processing of: visual, auditory information, sleep and arousal (‘alertness’)
    1. Reticular formation is a network of neurons that runs through the centre of the midbrain, hindbrain and brain stem towards the forebrain.
      1. Reticular activating system (RAS) screens incoming sensory information and regulates arousal
  3. Hindbrain controls motor function and vital and automatic responses such as breathing + heart rate + sleep + arousal
    1. Pons is involved with sleep, dreaming and arousal
    2. Medulla controls vital body functions
    3. Cerebrum coordinates movement, balance and precision
5. The role of the cerebral cortex
  1. Cerebral cortex is divided into 4 lobes
    1. Frontal Lobe function is to initiate and execute voluntary motor activity, planning and speech
      1. Primary motor cortex responsible for the planning, initiation and performance of specific movements
      2. Broca’s area responsible for articulate speech
    2. Parietal Lobe receives and processes sensory information
      1. Primary somatosensory cortex receives and process sensory information from the skin and body parts.
    3. Temporal Lobe processes auditory perception and has a role in memory, visual perception including facial recognition and emotional responses to sensory information.
      1. Primary auditory cortex receives and processes sound from both ears
      2. Wernicke’s area is responsible for speech comprehension and interpreting the sounds of human speech
    4. Occipital Lobe receives and processes visual information
      1. Primary visual cortex is the largest area of the occipital lobe and responsible for processing visual information
Brain plasticity and brain damage
1. Development and changes in brain structure and function
  1. Development
    1. Myelination is the growth and development of myelin
    2. Synaptogenesis is the formation of new synapses between the brain’s neurons.
    3. Synaptic pruning is a process where synaptic connections are eliminated which is designed to fine tune the neural connections
  2. Neural pathways and connections
  3. Frontal Lobe development
2. Brain Plasticity = the ability for the brain to change in response to experience
  1. Adaptive plasticity is the ability of brain to compensate for loss of function or maximize the remaining functions
    1. Rerouting = undamaged neuron that has lost a connection will seek a new active neuron
    2. Sprouting = growth to form new connections. This process involves rerouting
3. Developmental plasticity is the development and consolidation of neural pathways in the foetal stage as well as in babies, children and adolescents
  1. 1. Proliferation = A foetus’s cells develop into neurons. Approx. 250,000/min
    1. 2. Migration = newly formed neurons move outward to their destination. The neuron’s role is determined by its location.
      1. 3. Circuit formation = axons of new neurons grow out to target cells and form synapses with them.
        4. Circuit pruning = elimination of excess synapses and neurons
        5. Myelination
  2. Sensitive period is a time when an organism is more responsive to certain stimulation
  3. Critical period is a narrow period where in development an animal is preprogrammed for learning to occur
4. Brain injury is any brain damage that impairs/interferes with the normal functioning of the brain, either temporarily or permanently.
  1. Biopsychosocial changes
    1. Biological changes are primarily physical. E.g. prefrontal cortex injury would affect motor activities
    2. Psychological changes are primarily emotional, personality and cognition which in turn can impact on behaviour. Persistent apathy, inability to plan (severe cases)
    3. Social changes are a breakdown in relationships, difficult to establish new relationships. Due to the combined biological and psychological changes.
  2. Neurological disorders
    1. Spatial neglect is a neurological disorder where individuals are unable to notice anything on either their left or right side. Patients believe there is nothing wrong with them
    2. Parkinson’s disease is a progressive neurological disorder that has both motor and non-motor symptoms
      1. Motor Symptoms: Tremors, Muscle rigidity, Slowness of movement, Postural inability
      2. Non-motor symptoms: Speech, Anosmia, Slow cognitive processing, Mental Health problems
      3. Treatments - Two types of dopamine-based medication to help people manage: Medication that is converted to dopamine by the brain called L-dopa. Based on levodopa which is a chemical converted to dopamine by neurons (a pre-cursor). Effectively stimulate the reception site of dopamine

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Unit 1 Psychology AOS 1: How does the brain function?

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