The Quantum brain (QB) question.
Thanks to the so-called Copenhagen interpretation, quantum mechanics has been connected with consciousness since its early days. The group around Niels Bohr suggested that  an observer is an essential part of quantum mechanics. Schrödinger's cat was an attempt to questioning that idea, not to explain it. Although many alternative interpretation have been proposed since then, the Copenhagen interpretation is still the predominant which will be found in most text books.