Neurons can be understood to be fairly directional. There is no direct electrical connection between neurons: there's actually a small gap between the upstrea

Neurons can be understood to be fairly directional. There is no direct electrical connection between neurons: there's actually a small gap between the upstream neuron and the downstream neuron. When the electrical signal reaches this gap, the up-stream neuron releases a chemical signal, which is processed by the down-stream. So the state of the up-stream neuron depends very little on the down-stream neuron: if the down-stream neuron is in it's refractory period and can't process the chemical signal, the up-stream neuron can still fire all day, and the chemicals it releases will essentially fall on deaf ears. That is a somewhat simplified view, and there is such a thing as retrograde signaling (chemical messaging from the post-synaptic neuron to the pre-synaptic neuron), but it's believed these signals have less to do with the primary flow of information in the brain, and probably relate to slower processes like modifying the strength of the chemical signal in the affected synapse.