Proust and Neuroscience at the table:
Marcel Proust lived in his memory. He would close his eyes and disappear. This is understandable: His life was a feeble thing. He rarely left his room. He read train schedules to fall asleep, and he slept a lot. He dutifully informed his mother of his bowel movements and thought he was allergic to the sun. Faced with this claustrophobic reality, wouldn't you live in your memory?

But Proust's sense of memory was no idle exercise in nostalgia. He believed that memory was life: We exist only in a remembrance of things past and are made up of those fragile details that somehow defy the corrosive passage of time. Indeed, Proust's fiction, full of languid and precious sentences, was a virtual case study in the idea of memory, its peculiar habits, and particular properties.

From his eight self-centered and exquisite novels, three basic truths of remembering emerge:
1. The sense of smell has a unique relationship with memory;
2. Memory is a simultaneous stab at truth and a lie;
3. Some memories persist unconsciously, without our even knowing we remember them.

While Proust was writing his rich soap opera set in Combray, starring himself in the role of Marcel, science pursued its own intuitive concepts of memory. It took a while to escape the influence of Freud, but once modern science discovered the concept of the neuron, consciousness soon became a summation of kinase proteins and ion channels. The soul vanished and the brain became a swollen gray source for everything. The search for the molecular details of mind and memory is an ongoing process, a Sisyphean struggle of scientific reductionism against unimaginable complexity. But to the endless surprise of science, it was not the first to faithfully describe memory. Instead, a writer with a taste for the precious and the buttery had, by sheer force of adjectives and loneliness, beat them all. Proust was a neuroscientist.

Proustian revelation #1: "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. And at once the vicissitudes of life had become indifferent to me, its disasters innocuous, its brevity illusory. It was me." In other words, Proust ate a cookie. He had a cup of tea too. But what Proust discovered was that the madeleine, via the sense of taste, summoned a once hidden memory to the conscious surface. The memory was not some sepia-colored Kodachrome, but something visceral, complete, and three-dimensional. The memory was a novel. Eight of them, to be precise.

Proust's intuitive idea of cerebral structure was absolutely right. The sense of smell is unique. It synapses directly on the hippocampus, the center of the brain's memory, whereas all our other senses are first processed by the thalamus, the source of language and logic. This neurological anomaly explains why something delicious creates silence at the dinner table: Faced with the divine, we have nothing worthwhile to say.

Proustian revelation #2: "Our senses, at least as they are instantly transferred to memory, falsify for us the real nature of the world.ŠOur memories are true to us, and perhaps that is all."
The scientific method, firmly invested in objectivity, has never excelled at explaining subjectivity. This is why we have art. But as science searches for the patterns of consciousness, it is forced to confront the idea that our sense of being is defined by its privacy: Each one of us sees the world differently. Memory exaggerates these subtly distinct views, refashioning reality's disorders and discrepancies into a coherent drama. In our sentimental daydreams, we are all unconscious fiction writers, the heroic protagonists of our own star vehicle. Our narratives, however, come at the expense of verisimilitude.

In a recent set of experiments by the labs of Joseph LeDoux at NYU and Karim Nader at McGill, scientists demonstrated that long-term memory requires protein synthesis (the neuronal equivalent of creativity). The injection of a chemical, which stops new proteins from being created, prevents the act of remembering from occurring. (This is diagnosed medically as retrograde amnesia, but what amnesiacs might lack is the ability to misremember.) Every time we remember, the neuronal structure of the memory, no matterhow constant it may feel, is delicatelytransformed. If you prevent the memory from changing, it ceases to exist.

So the purely objective memory, the one "true" to the original taste of the madeleine, is the one memory forever lost to you. The moment you remember the taste is the same moment you forget its true flavor; the present is constantly corrupting the past. To put it another way, memories are like photographs, vulnerable to the grease of our fingertips. You touch them too much and all you see are the markings of your own hand.

Proustian revelation #3: "But when from a long distant past nothing subsists, after the people are dead, after the things are broken and scattered, taste and smell alone, more fragile but more enduring, more unsubstantial, more persistent, more faithful, remain poised a long time, like souls, remembering, waiting, hoping, amid the ruins of all the rest; and bear unflinchingly, in the tiny and almost impalpable drop of their essence, the vast structure of recollection."

Some memories exist outside time, like magic carpets folded delicately in our mind. But even as our memories define us, they exist without us. Science has never understood how untouched memories persist. How do we continue to know what we don't remember? How does the mind remain hidden from itself? How does an entire novel, or eight of them, just lie away waiting for a madeleine?

Scientific rumors (also known as gossip with acronyms) are emerging that might unlock the molecular details of this Proustian paradox. Because the theory is still an unpublished hypothesis, it lacks the sterile significance of "scientific truth," but the eloquence of its logic is tantalizing. A researcher (he insists on anonymity until the data is complete) believes he has found the "synaptic mark" of memory, an invisible linger that endures in the far electrical reaches of neurons. This molecule could be the reductionist answer to Proust's search for the origins of his past.

This avant-garde theory is based on the memory molecule's strange structural properties, which can change its shape without any genetic instruction. Like a sculptor molding clay, repeated stimulation with serotonin, a chemical released by neurons when you think, changes the form of the molecule. Once remodeled, this new molecular sculpture is cast in a metaphorical bronze (resistant to all the cellular weathers) and goes on to "mark" a specific neuronal connection as a memory. The protein's shiny new bronzed state recruits the requisite synaptic architecture needed for long-term remembrance and voilà! The memory is born in the brain.

This molecule (if the theory is true) is the synaptic element that exists outside time. Its presence explains how sentimental ideas endure, how idle experience can become a perpetuating pattern of neuronal connection. It is why the details of Combray could exist silently below the surface, tucked behind the curtain of consciousness. This theory feels true, illuminating a possible cellular reality so beautiful, so elegant, an artist could have dreamed it.

Proust would not be surprised by any of these scientific discoveries. He fancied himself a teller of truth, insisting: "It is the task of art to travel back in the direction from which we have come to the depths, where what has really existed lies unknown within us." Even at his most decadent, Proust was still deductive. He described the world as he saw it, the sensitive reality he felt. Though science has unraveled many rainbows, when it comes to understanding the meanings of the mind, scientists might benefit from a close reading of some beautiful prose.