Hyperpolarizing graded potentials can be caused by: (choose all the correct answers)

 As you learned, graded potentials can be hyperpolarizing or depolarizing. 

The ions that flow in @ the dendrites/soma will diffuse outwards in all directions.

 Some will end up at the axon hillock where they will either trigger an action potential (A.P.) or not.

Consider:

An A.P. is triggered when a threshold potential of -55mV is reached at the hillock.

Hyperpolarizing graded potentials would drive the membrane more negative than -70mV

Depolarizing graded potentials would drive the membrane more positive than -70mV

Review what types of ion channels can be opened @ dendrites/soma (last week's lecture)

Hyperpolarizing graded potentials can be caused by: (choose all the correct answers)

1.   Opening of photo-gated Cl- channels 
2.   Opening of ligand-gated Ca2+ channels 
3.   Closing of voltage-gated Na+ channels 
4.   Opening of mechanically-gated K+ channel

reference key insight