  In the last decades, important progress has been achieved in the
understanding of the neurotrophic effects of intermittent fasting (IF), caloric
restriction (CR) and exercise. Improved neuroprotection, synaptic plasticity
and adult neurogenesis (NSPAN) are essential examples of these neurotrophic
effects. The importance in this respect of the metabolic switch from glucose to
ketone bodies as cellular fuel has been highlighted. More recently, calorie
restriction mimetics (CRMs; resveratrol and other polyphenols in particular)
have been investigated thoroughly in relation to NSPAN. In the narrative review
sections of this manuscript, recent findings on these essential functions are
synthesized and the most important molecules involved are presented. The most
researched signaling pathways (PI3K, Akt, mTOR, AMPK, GSK3$\beta$, ULK, MAPK,
PGC-1$\alpha$, NF-$\kappa$B, sirtuins, Notch, Sonic hedgehog and Wnt) and
processes (e.g., anti-inflammation, autophagy, apoptosis) that support or
thwart neuroprotection, synaptic plasticity and neurogenesis are then briefly
presented. This provides an accessible entry point to the literature. In the
annotated bibliography section of this contribution, brief summaries are
provided of about 30 literature reviews relating to the neurotrophic effects of
interest in relation to IF, CR, CRMs and exercise. Most of the selected reviews
address these essential functions from the perspective of healthier aging
(sometimes discussing epigenetic factors) and the reduction of the risk for
neurodegenerative diseases (Alzheimer's disease, Huntington's disease,
Parkinson's disease) and depression or the improvement of cognitive function.
