It is mental experimental synthesis upon earlier paragraphs.
From the en.wikipedia.org
Absent this suppressor, protein synthesis is exaggerated, producing a range of mental and physical disorders.
From the sciencedaily.com
However, as these amino acids are necessary for protein and neurotransmitter synthesis, Phe buildup hinders the development of the brain, causing mental retardation.
From the en.wikipedia.org
Mental toughness and other qualities of mind needed for leadership can be developed by introspection, analysis of situations, synthesis of action plan, and implementation.