Readers question photons colliding, black sea snakes and more

Brain boost

It’s possible that therapies such as external brain stimulation and neurofeedback, as well as some drugs, may one day boost brain flexibility. A new line of research suggests flexibility is important for learning, Laura Sanders reported in “Learning takes brain acrobatics” (SN: 9/16/17, p. 22).

Online reader Glenn wondered if drugs for Parkinson’s disease and Huntington’s disease that help with movement problems could also remedy learning difficulties that accompany these conditions.

“Currently, there are no drugs that