Neuroplasticity and Neurotransmission Notes

Neuroplasticity

  • Definition: The brain's ability to change and adapt its connections between neurons over time, often in response to environmental factors.
    • Involves rearranging connections between neurons.
    • Facilitates the creation of new neural pathways.
    • With frequent use, these pathways strengthen, enhancing synaptic connections.
    • Analogy: Brain as a garden, neuroplasticity as the gardener.
      • Learning something new is like creating a new path.
      • Practicing a skill strengthens the path.
      • Well-worn paths are easier to navigate, mirroring skill mastery.
    • Enables learning, habit formation, and behavioral changes.

Key Terminology

  • Formation of Neural Networks
    • Highly interconnected network of neurons that send electrical signals to each other to help humans process information.
  • Neurons
    • Nerve cells that transmit messages throughout the body using electrical and chemical signals.
    • Enable various functions like talking, walking, and writing.
    • Communicate via neurotransmitters across synapses.
  • Synapses
    • Connections between neurons; each neuron has multiple synapses.
  • Dendrites
    • Branch-like structures on neurons that receive messages.
  • Synaptic Plasticity
    • The brain's ability to change and adapt connections between neurons.
    • Essential for learning, memory, and adapting to new experiences.
  • Long-term Potentiation (LTP)
    • Strengthens connections between neurons that are frequently used.
    • Critical for learning and memory.
  • Long-term Depression (LTD)
    • Weakens connections between neurons that are not frequently used.
    • Aids in forgetting or adjusting.
  • Neural Pruning
    • The process where unused synapses decay and disappear.
    • Increases brain efficiency by clearing space for quicker connections.

Neural Networks and Synaptic Pruning

  • Neural Networks:
    • Definition: Interconnected neurons that transmit electrical signals to process information.
  • Neural Pruning:
    • Definition: Elimination of unused synapses to enhance brain efficiency.
    • Infants are born with numerous neurons and potential connections.
    • Unused connections are pruned away during development.
    • Result: A more efficient neural network with faster connections.

Neurotransmission

  • Definition: The process by which neurons communicate by sending chemical messages.
    • Underlies various behaviors and functions, including mood, sleep, learning, memory, sexual arousal, and mental health.
    • Different neurotransmitters influence different behaviors.
    • Neurons transmit electrical impulses and release neurotransmitters across synapses.
    • Neurotransmitters are received by receptors on other neurons.
    • Analogy: Neurons as houses, neurotransmitters as mail carriers, synapses as the space between houses.

Neurotransmitters

  • Definition: Chemicals that transmit messages in the brain and nervous system.

Inhibitory Neurotransmitters

  • Decrease the likelihood of a neuron firing an action potential, calming the nervous system.
  • Prevent overexcitation, which could lead to seizures or anxiety.
  • Regulate mood, sleep, and motor control.
  • GABA:
    • Slows down brain activity.
    • Reduces overactivity.
    • Promotes relaxation and can alleviate anxiety.

Excitatory Neurotransmitters

  • Increase the likelihood of a neuron firing.
  • Roles include learning, memory, cognitive function, motor control, and sensory information.
  • Dopamine:
    • Associated with reward, motivation, and pleasure.
    • Released during rewarding experiences.

Molecules Affecting Neurotransmitters

  • Antagonist:
    • Reduces the effect of a neurotransmitter by blocking receptor sites.
  • Agonist:
    • Increases the effect of a neurotransmitter by helping it bind to the receptor.

Key Neurotransmitters and Their Roles

  • Serotonin
    • Role: Regulates mood, sleep, and appetite; contributes to well-being and happiness.
    • Effect: Low levels linked to depression, anxiety, and insomnia; balanced levels support emotional stability.
  • Acetylcholine
    • Role: Muscle movement, memory, and learning; found in both the CNS and PNS.
    • Effect: In CNS, involved in attention, learning, and memory. In PNS, transmits nerve impulses to muscles. Low levels associated with Alzheimer's; nicotine acts as an agonist.
  • Dopamine
    • Role: Reward, motivation, pleasure; movement and emotional responses.
    • Effect: Linked to pleasure and reward; significant role in addiction. Imbalance linked to Parkinson's (too little) and schizophrenia (too much).
  • Adrenaline
    • Role: Neurotransmitter and hormone during stressful situations (fight or flight).
    • Effect: Prepares the body for action by increasing heart rate, blood pressure, and energy; heightens alertness and focus.