1. Synaptic Coupling

2. Two Types of Synapses Pereda et al., Nat. Rev. Neurosci., 2014
Camillo Golgi – “Reticular theory”
1906 Nobel Prize in Physiology or Medicine

3. Two Types of Synapses Pereda et al., Nat. Rev. Neurosci., 2014
Santiago Ramón y Cajal – “neuron theory”
Shared Nobel Prize with Golgi in 1906

4. Gap Junctions Mediate Electrical Coupling
Each connexon has 6 identical subunits

5. Gap Junctions Mediate Electrical Coupling
Electron micrograph shows a row of gap junctions

6. Electrical Synapses are Ubiquitous in the Central Nervous System and Elsewhere
Insulin-secreting pancreatic β-cells are electrically coupled

7. Current Flows at an Electrical Synapse

9. Neurotransmitters are Packaged Into Synaptic Vesicles

10. Synaptic Vesicles Appear in Electron Micrographs
SV = synaptic vesicle
ax = axon
d = dendrite

11. There are Two Types of Neurotransmitter Receptors

12. The Receptors are Membrane-Spanning Proteins
outside
inside
Molecular model of a G-protein coupled receptor

13. Fast Spike-mediated Synaptic Transmission

14. The Vertebrate Neuromuscular Junction – A Model Synapse

15. Synaptic Input Can Be Excitatory or Inhibitory
EPSP=Excitatory Postsynaptic Potential
IPSP=Inhibitory Postsynaptic Potential

16. Synaptic Strength Exhibits Short-Term Plasticity
Depression usually caused by rundown of docked vesicles in the
readily releasable pool

17. Synaptic Strength Exhibits Short-Term Plasticity
Depression can also be due to inhibition of presynaptic Ca2+ channels

18. Synaptic Strength Exhibits Short-Term Plasticity
Facilitation can be caused by buildup of free Ca2+ in the synaptic
terminal or the buildup of Ca2+ bound to exocytotic binding sites

19. Synaptic Strength Exhibits Short-Term Plasticity
Facilitation can occur with the accumulation of presynaptic free Ca2+
or Ca2+ bound to sites on the docked vesicles

20. Synaptic Strength Exhibits Short-Term Plasticity
Internalization or inhibition of postsynaptic receptors

21. Synaptic Strength Exhibits Short-Term Plasticity
Some receptors remain bound between stimuli

22. Synaptic Strength Also Exhibits Long-Term Plasticity
SDSP = Spike Timing Dependent Synaptic Plasticity

23. Synaptic Strength Also Exhibits Long-Term Plasticity
LTP = Long Term Potentiation

24. And Structural Reorganization
Developmental changes in synaptic organization

25. This Remodeling Involves Removal or Addition of Dendritic Spines

26. This Remodeling Involves Removal or Addition of Dendritic Spines

27. This Remodeling Involves Removal or Addition of Dendritic Spines
Image of spines in a striatal neuron

28. Growth of a Dendritic Spine