Dr. Geoff Bunn presents a journey through 5000 years of our understanding of the most complex thing in the known universe: the brain, in this major ten-part BBC Radio 4 series.

In Episode 5, 'The Spark of Being', the focus is on electricity and communication, within the brain and between the brain and the rest of the body. When John Walsh showed, in 1776, that an eel could generate electricity, it became possible that human consciousness also relied on sparks fizzing within the brain. Coming at a time when Benjamin Franklin – an acknowledged expert on electricity – was signing the Declaration of Independence which asserted that all men are created equal, it generated a new perspective on the workings of the brain; the old heirarchical model was discarded in favour of the doctrine of equipotentiality.

The series is entirely written and presented by Dr Geoff Bunn of Manchester Metropolitan University, with actors Paul Bhattacharjee and Jonathan Forbes providing the voices of those who have written about the brain from Ancient Egypt to the present day, and actor Hattie Morahan giving the Anatomy Lesson which establishes the part of the brain to be highlighted in each episode – in this instance the Corpus Callosum. The original, atmospheric score is supplied by composer, Barney Quinton. Producer: Marya Burgess.