Sir Charles Sherrington is one of the greatest names in the history of neuroscience, and
especially in neurophysiology. His book ‘The Integrative Action of the Nervous System’ – dating from a series of lectures in Yale (1906) is still an absolutely amazing read. Sherrington was a most beautiful and elegant writer. Introducing the term ‘the synapse’, he writes as follows:
It seems therefore likely that the nexus between neurone and neurone in the reflex-arc, at least in the spinal arc of the vertebrate, involves a surface of separation between neurone and neurone; and this as a transverse membrane across the conductor must be an important element in intercellular conduction. The characters distinguishing reflex-arc conduction from nerve-trunk conduction may therefore be largely due to intercellular barriers, delicate transverse membranes, in the former. In view, therefore, of the probable importance physiologically of this mode of nexus between neurone and neurone it is convenient to have a term for it. The term introduced has been synapse.
Nobody writes like this anymore – not in neuroscience anyway: the writing is both information dense and beautifully-posed. Phrases like ‘delicate transverse membranes’ capture still the prevailing image of the synapse. This book is long since out of copyright, and is downloadable in multiple formats (including Kindle!) here; many of his full-text papers are here. This is his Nobel Prize biography. And here’s a superb appreciation; and here some memories of a laboratory world that no longer exists; another excellent perspective; and an obituary of David Whitteridge, Sherrington’s successor, who among many discoveries gave us the cortical magnification factor – the idea that ‘proportionately more cortical surface was devoted to the representation of the fovea than the retinal periphery’.
Sherrington is famous for another metaphor – that of the ‘Enchanted Loom‘:
The great topmost sheet of the mass, that where hardly a light had twinkled or moved, becomes now a sparkling field of rhythmic flashing points with trains of traveling sparks hurrying hither and thither. The brain is waking and with it the mind is returning. It is as if the Milky Way entered upon some cosmic dance. Swiftly the head mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of subpatterns.
This is from his book, Man on His Nature. It’s not quite correct. The brain is hardly less active in sleep than it is during waking; however, the sentence that the ‘brain is waking and mind is returning’ feels introspectively correct as describing the way the amnestic fog of sleep dissipates and consciousness is back – whatever the reality is actually happening in the brain.