Neural basis of learning

Neural basis of learning

1. Neural pathways

   • Learning:Learning is defined as a relatively permanent change in behaviour that occurs as a result of experience
     • Learning is an ongoing process that continues throughout the life span, enabling us to adapt and cope in an ever-changing world. Learning may occur intentionally or unintentionally and can also be active or passive.
     • When a neuron is stimulated it produces an action potential and when the action potential gets to the end of the axon terminals of the presynaptic neuron it stimulates the release of a neurotransmitter called GLUTAMATE into the synaptic gap between the presynaptic neuron and the dendrites of a neighboring postsynaptic neuron.
       • neurotransmitter strengthens connections
     • dopamine:release of dopamine at this time provides a pleasurable experience. This positive consequence rewards the activity motivating the individual to repeat it.
     • repeated stimulation
       • Hebbian learning: if two neurone are active at the same tie, the synapse between them are strengthened, thus facilitating the passage of nerve impulses along a particular circuit.
         • long term potentiation: Hebb's hypothesis lead to the discovery go LTP-refers to long-lasting strengthening of the synaptic connections of neurons, resulting in a more effective functioning of the neurons whenever they are activated. LTP is a crucial neural mechanism that makes learning possible.
     • as the brain receives specific appropriate input through the senses or processes information, with appropriate frequency, intensity and duration, the brain physically changes its structure
   • Neurons
     • Proliferation is the first processes, which refers to the production of new cells/ neurons in the brain primarily occurring early in life.
       • Early in development, the cells lining the ventricles divide where some cells become stem cells where others remain where they are or become neurons.
       • Migration, which refers to the movement of newly formed neurons and glia to their eventual locations.
         • Migration occurs in a variety of directions throughout the brain and cells following chemical paths in the brain
       • Myelination occurs which is the process by which glia produce the fatty sheath that covers the axons of some neurons called the myelin sheath and occurs gradually for decades.
       • synaptogenesis that refers to the formation of the synapses between neurons.
         • synaptogenesis occurs throughout the life as neurons are constantly forming new connections. The process slows significantly later in the lifetime.

2. plasticity : refers to the brains ability to change and reorganise itself by forming new neural connection throughout life

   • developmental plasticity :brains natural ability to form new connections in order to process sensory information from environmental stimulation
     • synaptic pruning: eliminates weaker synaptic contacts while stronger connections are kept and strengthened
   • adaptive plasticity: is the brains ability to form new connections to recover or compensate for lost function and\or to maximise remaining functioning in the event of brain injury
     • Axonal sprouting: undamaged axons grow new nerve endings to reconnect neurone whose links were injured or severed
     • rerouting : undamged neurone that has lost connection with an active neurone may seek a new active neurone and connect with it instead

3. structure

   • soma
     • dendrites
     • axon
       • myelin sheath
       • axon terminal
         • synaptic gap
           • neurotransmitter
             • post synaptic neuron

4. Maturation and development

   • maturation: involves the orderly, sequential changes the body is genetically predetermined to undertake
   • critical periods:optimum times for the development of certain pathways in response to appropriate stimulation
   • sensitive periods: when an organism is more responsive to certain environmental stimulus or experiences
     • experience dependent learning
       • particular learning
     • experience expectant learning
       • experience = unexpected
   • reflex: innate, automatic reaction involving a simple rapid response to a specific stimulus, which does not depend on conscious thought or processing