Final answer:
Brain substances involved in neuron growth and survival mainly include neurotrophic factors, neurotransmitters like dopamine and serotonin, and glial-cell-derived signals, with a significant role played by glia such as astrocytes and oligodendrocytes.
Step-by-step explanation:
Substances in the brain that are involved in the growth and survival of neurons include a variety of neurotrophic factors, neurotransmitters, and glial-cell-derived signals. Glia, such as astrocytes and oligodendrocytes, play crucial roles in neurite outgrowth, synaptic plasticity, and the formation of myelin sheaths that protect and insulate axons. Neurotransmitters like dopamine, serotonin, and norepinephrine are pivotal for neuron communication but also influence neuron development and synaptic plasticity. Amino acids like glutamate and GABA (gamma aminobutyric acid) are critical for excitatory and inhibitory signaling in the brain, respectively. Astrocytes particularly aid in synaptic formation and neuron repair, highlighting their significance in neuron survival.