[bad-joke]

> 1) Neurogenesis halts in your early 20s. After that, no new neurons for you, sorry. Although the connections may change.

This statement as written is almost total nonsense. A cursory internet search yields abundant studies on adult neurogenesis. Even small amounts of cardiovascular exercise increase brain volume, stimulate neural growth, and create synaptic connections in adults well into old age.

At best, one could claim that neuron growth slows as we age, but it absolutely doesn't halt.

[bitwize]

And yet when Arturo Alvarez-Buylla and his team of researchers actually searched for physical evidence of young neurons in adult brains, they found... nothing: https://www.nature.com/articles/nature25975

The studies which came before may be based on nonprimate animal models in which adult neurogenesis does occur. But the best evidence we have to date suggests that adult humans do not grow new neurons.

[p1esk]

That article you linked to is about neurogenesis in hippocampus only.