7. Mind the Gap

Dr Geoff Bunn's ten-part history is a journey through 5000 years of our understanding of the most complex thing in the known universe.

From Neolithic times to the present day, Geoff journeys through the many ideas of what the brain is for and how it fulfils its functions.

What soon becomes obvious is that our understanding of this most inscrutable organ has in all periods been coloured by the social and political expedients of the day no less than by the contemporary scope of scientific or biological exploration.

In this episode, the focus is on how the microscope allowed neurologists to detail the structure of brain cells. While Sigmund Freud, who started out as a neurologist, had hoped his gold chloride staining method would revolutionise brain research, it was in fact Camillo Golgi's La Reazione Nero, using silver nitrate, that enabled brain scientists to see the cell composition more clearly. Combined with the Gudden microtome, which provided extremely thin sections of brain tissue, neurologists began to explore how neurons are connected, with Charles Sherrington coining the term synapse to describe the gap between them.

Featuring the voices of Paul Bhattacharjee, Jonathan Forbes and Hattie Morahan.

Produced by Marya Burgess.

First broadcast on BBC Radio 4 in November 2011.