Synaptic Integration and Synaptic Transmission Lab Objectives

Overview

• Focus on synapse events in two neurons.
• Review concepts from previous labs regarding action potentials and intracellular communication.

Key Concepts

Synaptic Transmission

• Action Potential Propagation: Travels down the axon to the axon terminal.
• Voltage-Gated Calcium Channels: Open at the axon terminal, causing calcium influx.
• Calcium's Role: Triggers exocytosis of neurotransmitters.
• Neurotransmitter Binding: Binds to ligand-gated channels on the post-synaptic neuron (dendrites/soma).
• Post-Synaptic Potential (PSP): A graded potential caused by neurotransmitter binding.

Graded Potentials vs. Action Potentials

• Graded Potentials:
  • Can summate (add together or subtract).
  • Decremental (lose strength as they travel).
  • Excitatory or inhibitory.
  • Involve ligand-gated channels on the soma and dendrites.
  • Strength related to stimulus strength.
• Action Potentials:
  • All-or-none (no partial action potentials).
  • Cannot summate due to the absolute refractory period.
  • Travel through saltatory conduction.
  • Involve voltage-gated channels on the axon hillock and axon.

Summation Concepts

• Temporal Summation: Stimuli from one presynaptic neuron firing repeatedly over time (like ringing a doorbell repeatedly).
• Spatial Summation: Stimuli from multiple presynaptic neurons simultaneously (like doorbells ringing at both front and back doors).

Electrochemical Gradients

• Practice Examples:
  • Potassium: Higher inside the cell, moves out chemically, and electrically attracted to negative ECF.
  • Anion: Higher inside, moves out chemically, attracted to positive ICF.
  • Cation: Higher outside, no net movement when at equilibrium potential.

Important Practices

• Draw arrows correctly on diagrams (directly on the cell, not separate).
• Provide complete analysis for each cell in multi-cell problems.

Lab Exercises

• Synapse Exercises:
  • Experiment with synapses: number, conductance, current, equilibrium potential.
• Key Terms:
  • Conductance: Number of open channels.
  • Current: Number of moving ions.
  • Equilibrium Potential: Membrane potential where electrical and chemical forces are equal and opposite.

Practical Application

• Understanding single synapse processes.
• Influence of neurotransmitters on channel opening and ion movement.

By mastering these objectives, you will gain a deeper understanding of synaptic events and their role in neuronal communication.