Psychology - Neurones

• Neuron

  A specialized cell in the body that transmits information electrochemically
• Types of neurons

  • Sensory neuron
  • Relay neuron
  • Motor neuron
• Sensory neuron

  • Detects information (e.g. pressure or heat) and passes it through the peripheral nervous system to the central nervous system
• Relay neuron


  • Detects information from the sensory neuron and can pass information to the central nervous system for processing, and can also pass information to motor neurons
• Motor neuron


  • Detects information from relay neurons and carries information to the muscle, making it contract or relax
• Reflex arc

  The collection of neurons that allows reflex actions, where the body moves quickly in response to possible danger
• Parts of a neuron

  • Dendrites
  • Cell body
  • Axon
• Dendrites

  The extensions of neurons that attach signals sent from other neurons
• Cell body

  Contains the genetic information of the nerve cell and controls the cell's functions
• Axon

  A long extension of the nerve cell that allows it to pass messages on to other nerve cells
• Myelin sheath

  Insulation that covers the axon, making the electrical signal or nerve impulse travel faster
• Sense receptors

  Specialized dendrites that detect external stimuli like heat, taste, or light
• Motor end plates

  Attachments at the end of motor neurons that connect them to muscle fibers, used to activate muscles
• Synapse

  The structure where a presynaptic neuron converts an electrical signal into a chemical signal that is detected by a postsynaptic neuron
• Synaptic transmission

  1. Presynaptic neuron releases neurotransmitters

  2. Neurotransmitters detected by receptors on postsynaptic neuron

  3. Neurotransmitters taken back into presynaptic cell by transport proteins
• Neurotransmitters

  Chemical molecules released by neurons that are detected at receptor sites
• Excitatory neurotransmitters

  Make the postsynaptic cell more likely to fire
• Inhibitory neurotransmitters

  Make the postsynaptic cell less likely to fire
• Summation

  The interaction between excitatory and inhibitory processes that determines whether the postsynaptic cell will fire
• Hebb's theory of learning and neural growth

  The idea that when we learn, our brain physically changes by creating new neural pathways
• Neuroplasticity

  The brain's ability to physically change in response to experience
• Cell assemblies

  Groups of neurons that fire together when we learn new things
• The more neural pathways are used, the stronger and more efficient they become
• Improvements in performance

  Are due to increased effort, as supported by Hebb's ideas about neural pathways becoming more efficient with use
• There is biological evidence of neurons growing new connections when electrically stimulated
• Effective learning is a complex problem that can't be fully explained just by the growth of new synaptic connections