L7: Synaptic Integration

why does 4 shocks delivered one after the other to a presynapse increase voltage much higher than if they were spread out?

due to temporal summation, the voltages build up and the 2nd neuron has no time to recover

where does synaptic integration take place?

at the axon hillock

why does location of IPSP or EPSP matter for neural firing?

closer to the base of the dendrite or soma means the graded potential does not have to travel as far and the cell is more likely to reach the action potentials threshold

How might a demyelinating condition impact the summation process?

Electrical signals might move down the axon too slowly, arriving later than other inputs and preventing the postsynaptic cell from firing

what is the difference between temporal and spatial summation?

temporal is how much signal from 1 neuron and spatial is how many neurons are signaling

what 3 factors must a postsynaptic cell integrate?

1. how much signal (temporal)

2. how many signals (spatial)

3. type of signal (IPSP or EPSP)

if a GABA-nergic neuron and glutamanergic neuron were to fire on a third neuron at the same time, what would be the effect on the third neuron's synapse?

there would be net no difference if they fired simultaneously because glutamate is excitatory and GABA is inhibitory

what would come in during an EPSP response?

an excitatory post-synaptic potential would have sodium come into the cell, to drive it towards depolarization (more positive)

how would ions flow during an IPSP?

an inhibitory post-synaptic potential would drive towards repolarization/hyperpolarization, so Cl- coming into the cell or K+ leaving the cell

If one neuron fires in the middle of the axon and another synchronized/identical neuron fires at the cell's dendrites, which has a stronger effect on the post-synaptic neuron?

the neuron that fired closer to the axon terminal where vesicles are released, so the one in the middle of the axon

what are the components of a synapse?

presynaptic cell, synaptic cleft, postsynaptic cell

what are nerves?

bundles of axons in the peripheral nervous system