The well-being of a neuron depends on its ability to communicate with other neurons. Studies have shown that electrical and chemical stimulation from both a neuron's inputs and its targets support vital cellular processes. Neurons unable to connect effectively with other neurons atrophy. Useless, an abandoned neuron will die.
Lisa Genova (2011). “Lisa Genova Box Set: Still Alice and Left Neglected”, p.213, Simon and Schuster