Introduction to Neuronal Synapses

Overview

• Previous Module Recap
  • Explored electrical properties of individual neurons
  • Membrane potentials from electrical forces and diffusion
  • Action potentials (spikes) generation and propagation
  • Need to understand collective behavior of neurons

Approach to Neuroscience

• Multiple scales and levels of analysis
• Course progression:
  1. Single molecules (ion channels)
  2. Electrical behavior of neurons
  3. Neuronal circuits
  4. Functional brain regions

Basic Cellular Anatomy of Neurons

• Neuron Polarization
  • Specialized regions for input (dendrites) and output (axon)
• Dendrites
  • Greek origin: "dendron" (tree)
  • Branching, tree-like structure
• Signal Transmission
  • Dendrite → Cell body
  • Depolarization initiates action potential
  • Action potential travels down axon

Synapses

• Definition: Junction between two neurons
• Types of Synapses
  1. Electrical Synapses
     • Simpler, direct ion passage
     • Fast, synchronous coupling
  2. Chemical Synapses
     • More complex, chemical release in synaptic cleft
     • Converts chemical signal back to electrical or other cellular effects
     • Slower but allows diverse and complex signaling

Importance of Synapses

• Critical for neuronal computations and signaling
• Influence on behavior

Future Topics in the Course

• Inner workings of chemical synapses
• Neuronal networks and behavior
• Defective synaptic physiology in disorders
• Synaptic targets for drugs and poisons
• Synaptic plasticity: Changes over time, role in learning and memory