Action Potentials and Synapses

Overview

• Neurons communicate through action potentials and neurotransmitters.
• Synapse: Junction where neuron A releases neurotransmitter due to an action potential, influencing neuron B.
• Balance of excitatory and inhibitory inputs to a neuron determines action potential occurrence.

Neuronal Communication

• Neurons are electrical devices; membrane channels allow ion flow.
• Resting membrane potential: -70 mV (inside more negative than outside).
• Inputs affect membrane potential, making it more positive (excitatory) or negative (inhibitory).

Action Potentials (AP)

• Fundamental communication units between neurons.
• Occur when membrane potential reaches approximately -50 mV (threshold).
• Termed as spikes; shape recorded via electrical equipment.

Synaptic Communication

• Action potential at presynaptic terminal releases neurotransmitter into the synaptic cleft.
• Synaptic cleft: 20-40 nm gap between neurons.
• Neurotransmitter binds to receptors on the postsynaptic side, influencing ion flow.

Key Terms

• Axon: Generates and transmits action potentials; causes neurotransmitter release.
• Dendrite: Receives synaptic inputs; determines neuron firing action potential.
• Membrane potential: Electrical potential across neuron's membrane.
• Action potential: Brief electrical event signaling neuron activity; triggers neurotransmitter release.
• Neurotransmitter: Chemical influencing excitatory or inhibitory effects on target neurons.
• Synapse: Junction for neuron communication via neurotransmitter.

Research at QBI

• Neuronal communication research by Professor Pankaj Sah.
• Synapse research by Dr. Victor Anggono and Professor Frederic Meunier.

Additional Resources

• Explore more topics like brain anatomy, disorders, synaptic plasticity, and types of neurons at the Queensland Brain Institute website.