Alexander "Axel" Borst (born August 18, 1957 in Bad Neustadt an der Saale) is a German neurobiologist.
Borst studied biology at the University of Würzburg, where he obtained his PhD as a member of Martin Heisenberg's group.
Afterwards, he led an Independent Junior Research Group at the Friedrich Miescher Laboratory of the Max Planck Society.
He discovered that dedicated brain structures known as mushroom bodies play a crucial role in olfactory learning in flies (Heisenberg, Borst, Wagner, Byers, J. Neurogenetics 1985).
Borst’s research aims to connect a formal, mathematical description of these processes with the underlying biophysical properties of nerve cells.