Behavioral Neuroscience, Lecture on September 26th
*Potassium and chloride channels are "leak" channels so they are open at all
times allowing ions to go in and out freely.
Depolarize or hyperpolarize?
*Disregarding the sodium-potassium pump.
What happens to the resting membrane potential if you....
>increase organic anions
>> more anions stay in the cell.
>Increase extracellular Cl-?
>> more Cl- enters the cell. Force of diffusion pushes more Cl- into the cell.
> increase extracellular Na+?
>> little to no effect because the ion channels are closed!
>> but if you increase it enough it may hyperpolarize.
> increase extracellular K+
>> more K+ stays in the cell.
>> the force of diffusion usually pushes potassium out but now the concentration
gradient due to increase of potassium is reduced so more potassium can stay in
Not all ion channels are the same.
> leak channels are located everywhere across the neuron.
> "chemically-gated" channels near the soma and dendrites. Neurotransmitters
activate these channels.
>> stay open as long as the transmitter is attached.
>> has a binding site where neurotransmitters attach. During attachment, the
site changes shape allowing ions to move through.
>> let's positive ions into the cell.
>> causes small local changes in memory potential called post-synaptic
potentials (PSP). they occur on dendrites and the cell body.
>> EPSPs increase chances of generating an action potential. (Excitatory)
>> IPSPs decrease chances of generating an action potential. (Inhibitory)
> the axon hillock integrates excitatory postsynpatic potentials and inhibitory
post synaptic potentials and