I've heard two theories about how neurons change their interconnections with each other. I'm just wondering which one of them, or both of them, are true.

 

1) The dentrites of one neuron branch out and make connections with other nearby neuron on their axons. To change a connection, the dendritic branches physical move away from one neuron and connect to another one.

 

2) Dendritic branches do not move from/to other neurons' axons. Instead the receptors at the connection site change in quantity and type. So if at one site, there are a lot of one kind of receptor that readily reacts to a neurotransmitter that is readily emitted at that site, this site can be easily used to transmit signals from the one neuron to the other. To change this, the quantity of receptors reduces (or changes type), thereby making the recipient neuron less likely to fire when the sender neuron transmits a signal to it. Therefore, this site is no longer useful for transmitting signals.

 

Are both these true? If not, which one is?

Anybody?

I'm pretty sure the dendrites do not connect to the axons, but rather exchange chemical synpases with other nearby dendrites.