Download Exercise 5: Synaptic Integration - הפקולטה למדעי הבריאות

BEN-GURION UNIVERSITY OF THE NEGEV
P.O.B 653, BEER-SHEVA 84105, ISRAEL
‫גוריון בנגב‬-‫אוניברסיטת בן‬
50145 ‫שבע‬-‫ באר‬,356 .‫ד‬.‫ת‬
‫המחלקה לפיזיולוגיה‬
‫הפקולטה למדעי הבריאות‬
Department of Physiology
Faculty of Health Sciences
Exercise 5: Synaptic Integration
Site of Impulse Initiation Tutorial
Experiments and observations
Where does the spike initiate and why?
Why is the action potential in the soma of reduced amplitude compared to that in the
axon?
Why is there an action potential in the dendrite if the dendrite is passive?
Can the site of impulse initiation be altered by parameter changes? Change
the synaptic strength (conductance).
Has the site of initiation changed with synaptic strength?
Change the location of the synapse on the dendrite.
Has the site of initiation changed with synaptic location?
Change the morphology of the soma.
Can you explain your results when you change the soma morphology?
Synaptic Integration Tutorial
Experiments and observations
Why is the voltage change in the initial segment so steep?
The EPSP occuring first will now be closest to the cell soma. Will this sequence of
EPSPs cause an action potential to initiate?
Deliver a train of synaptic inputs at a single synaptic location.
Can you explain why three EPSPs in a train generate a spike when the same EPSPs
occuring simultaneously do not?
What do these relations tell you about voltage spread in a passive dendritic arbor?
How does threshold change with position of the synapse on the dendrite for EPSPs
occuring simultaneously? Explain.
How does inhibitory synaptic input (IPSP) at one synapse affect voltage
spread and impulse initiation?
How does inhibitory synaptic input (an IPSP) at one synapse affect voltage spread
and impulse initiation? For the IPSP, explore the effect of changing (increase the
conductance of the two remaining excitatory synapses to 2.5 nS):
1.
Its onset time with respect to EPSPs
2.
Its location