ESSAYS: Proust was a neuroscientistby Jonathon Lehrer, Canongate, 242pp, £16.99

WE ASSUME neuroscientists were the first to understand the brain, but Jonah Lehrer (author of the best-seller The Decisive Moment)believes intuitive artists often understood brain function long before scientists did, and in his new book he makes a convincing case for this hypothesis.

Proust Was a Neuroscientistis a collection of essays about eight neurologically prescient artists: Walt Whitman, George Eliot, Auguste Escoffier (a slight stretch), Marcel Proust, Paul Cézanne, Igor Stravinsky, Gertrude Stein and Virginia Woolf.

Every essay convincingly explores the subjects' neurological foresight, but the one on Marcel Proust (1871-1922) and his novel In Search of Lost Timemay be the best, and it certainly gives a good sense of the way Lehrer synthesises aesthetic insight and science.

Proust’s opus begins with a section (entitled ‘Overture’) that opens with the adult narrator (Proust’s avatar, Marcel) describing his current state of mind and closes (more or less) with the famous account of eating a madeleine and drinking lime-flower tea and the effect this has on him:

No sooner had the warm liquid mixed with the crumbs touched my palate than a shudder ran through me and I stopped, intent upon the extraordinary thing that was happening to me. An exquisite pleasure had invaded my senses, something isolated, detached, with no suggestion of its origin . . .

I drank a second mouthful, in which I find nothing more than in the first, then a third, which gives me rather less than the second. It is time to stop. The potion is losing its magic. It is plain that the truth I am seeking lies not in the cup but in myself.

And what Marcel strives to locate in himself in the 3,500 pages that follow is his past, but what his memory offers up is skewed, partial and unreliable, a simulacrum.

UP TO PROUST, by and large, memory was believed to be more or less purposeful (when the ego issued directions it did its best to oblige), and, although no one claimed memories were infallible, nobody posited that memories were deliberately constructed lies, either. The best comparison was with film: memories were like old films retrieved from cranial storerooms and projected on the cinema screen inside the skull: the colours might be weird and the pictures jerky, but the content was basically true.

Proust’s theory of memory asserted the reverse: the mental associations that flowed from a stimulus were as likely to be random as logical, and, moreover, all memories were phoney, so though they felt real they were really elaborate fabrications.

What Proust proposed, neuroscientists (and Freud), even as Proust was composing, were groping towards. It was Santiago Ramón y Cajal (recipient of the 1906 Nobel Prize in Medicine) who first hypothesised that the cells in the brain aren’t arranged in a seamless web but stand alone and that the gaps between cells – now known as synaptic clefts – are the sites of memory and communication. He was right: memories exist in the synapses, and this storage system explains the haphazardness of memories when one remembers.

Take the madeleine-and-lime-flower-tea moment in the “Overture” again: the narrator consumes: this excites smell and taste neurons in his brain, and then neurons downstream holding childhood memories of Combray and Aunt Léonie fire up. It was in Combray with Léonie that the narrator had his first madeleine-and-lime-flower-tea moment, so this is logical. However, the madeleine-and-lime-flower- tea experience in the “Overture” also stimulates other memories; for instance, “the game wherein the Japanese amuse themselves by filling a porcelain bowl with water and steeping in it little pieces of paper”. This has nothing to do with his childhood; it just happens to lie downstream of his taste neurons. Thus today we can explain the random nature of recall posited by Proust a century ago with what we know about brain structure, but what about the falsity of content? The answer to this lies with the chemistry.

What exactly happens chemically during recall isn't understood completely, but it's known now by neuroscience that proteins are made when this happens and that in turn means the following: when we remember, what we're remembering is incorporated along with the present in which it is being remembered into the architecture of the brain and made permanent by new proteins created by the process of retrieval. So remembering changes the brain's structure, and the more a memory is remembered the more the structure changes, and the more the brain's structure changes the more the memory is modified to fit what we know now.

In Lehrer's judgment Proust's intuition of what is now a neurological certainty – memories are constructions that meld past and present – is remarkable, but in his opinion Proust's greater achievement was to understand why. What Proust grasped (as neuroscience has today) was that without the transformative process there was no memory: in Lehrer's words, "We have to misremember something in order to remember it."

I can’t think of a better bannister to hold on to when reading Proust: once you know this vast novel is the story of a character, Marcel, who has to take the false and the not-accurate or else settle for nothing, then everything in it makes sense.

Lehrer’s book is short. Yet despite its brevity he packs in an enormous amount of history and biography, science and criticism. There is more content here than in many books three times as long. He’s also a fine writer whose sentences are always lovely and pure and comprehensible.

I’ve heard it said that we live in a golden age as far as science writing is concerned. I’ve no idea, but I do know a golden book when one bumps into me, and this is one.

Carlo Gébler's play Charles & Mary, about the Lamb siblings and the composition of their Tales from Shakespeare, has just been published by the Lagan Press and will be broadcast on BBC Radio 3 tomorrow at 8pm. His novel The Dead Eightwill be published by New Island this summer