1. Postsynaptic Potentials
Lesson 10

2. Postsynaptic Potentials
Signaling in Dendrites & Soma
Vm changes
dendrites & soma
Excitatory: +
Inhibitory: ~

3. Postsynaptic Potentials - PSPs
Chemically-gated ion channels
Graded
Summation
Duration
10 – 100 milliseconds
Velocity
Fast  approximately speed of light
Decremental
Weaken over time & space ~

4. EPSPs Excitatory Postsynaptic Potential Depolarization (+)
Vm becomes more positive
Na+ influx ~

5. Vm EPSP + + - Record here Depolarization more likely to  AP ~ Time
-55 mV
- 65 mv
AT REST -
Time

6. Vm Temporal + Summation + - 2 pulses same synapse ~ Time -55 mV
AT REST -
Time

7. Vm Temporal + Summation + - Time Repeated stimulation -55 mV - 65 mv
AT REST -
Time

8. Vm Spatial + Summation + + - Time Multiple synapses -55 mV - 65 mv
AT REST -
Time

9. IPSPs Inhibitory Postsynaptic Potential similar to EPSPs
EXCEPT opposite
hyperpolarization (-)
Vm becomes more negative
K+ efflux ~

10. Vm IPSP - + - Time Hyperpolarization less likely to fire
also summate (max) Vm
-55 mV
- 65 mv
AT REST -
Time

11. EPSPs & IPSPs summate CANCEL EACH OTHER Net stimulation
EPSPs + IPSPs = net effects
*Integration ~

12. +
EPSP
IPSP -
- 65 mv

13. Postsynaptic Potentials
Soma & Dendrites
Chemically-gated channels
Passive current
Graded
Summation
EPSP
Excitatory
Depolarization
Na+ influx
AP more likely
IPSP
Inhibitory
Hyperpolarization
K+ efflux
AP less likely