Continuing with my mind’s eye: on a grubby ceiling, there were two overhead fans beating to little effect, and at the rear of the shophouse rose an elderly wooden staircase to God knows where. Now and again an Indian man would appear from the street, walk the length of the eating house and disappear upwards into the gloom.

Above was either a cheap boarding house or a knocking shop. Or maybe both. I was never inclined to venture above to find out. Beneath the stairs were stacked sacks of rice, bags of cement, crates of soda, folding chairs and commodities of the like. I invariably drank one beer while eating the paratha and took another can back with me to sup in the hotel.

That was what I remembered.

But the original eating house was no longer there, neither was its dough maestro, nor was its Chinese beer seller. In its place was another restaurant much cleaner, brighter and well ventilated than the original.The curry was familiar enough, the bread was close enough, and the beer was just as cold. Yet somewhere between one side of Geylang Road and the other lay the distance between remembering and returning.

I was disappointed, but after wandering for five minutes, I found a similar establishment across the road.

I do not have teddy bear sex anymore -- a lack of flexibility in the thigh muscles --  though I do miss the strawberry jam at the end.


THINKING ABOUT THINKING
The Neuron — The Messenger

If we are going to understand memory, consciousness, thought, fear, pleasure, or even the strange experience of arriving alone in an unfamiliar railway station, we must begin with something surprisingly small: the neuron.

A neuron is a specialised living cell whose job is to receive, process and pass on information. There are billions of them in the human brain, each connected, directly or indirectly, with vast numbers of others. Individually, a neuron is not particularly impressive. It cannot think. It does not contain a memory of your childhood or an opinion about the hotel you have just checked into.

But put roughly 86 billion of them together, connect them in extraordinarily complicated ways, and something remarkable happens. You happen.Your memories. Your fears. Your personality. The sound of music. The taste of mango. The face of someone you loved fifty years ago. The irritation of being stuck on a third-class train. The sudden feeling, on arriving somewhere entirely new, that you are awake and intensely alive. All of these experiences depend upon neurons communicating with one another.

The anatomy of a neuron
A typical neuron has several important parts.The dendrites are like branches growing from the cell. Their job is largely to receive information from other neurons. Thousands of signals may arrive at a neuron through these branching structures.

At the centre is the cell body, which keeps the neuron alive and integrates much of the information it receives. You might think of it as the neuron's headquarters.If the incoming information is sufficiently important, the neuron sends a signal along a long fibre called the axon. This signal travels away from the cell body towards other neurons. But there is a catch. Neurons usually do not actually touch one another.

Between one neuron and the next is a tiny gap called a synapse. When an electrical signal reaches the end of an axon, it triggers the release of chemical messengers called neurotransmitters. These cross the tiny gap and influence the next neuron.

So the basic pattern is:Receive → decide → transmit → influence another neuron. And then it happens again. And again. And again. Millions of times every second: A conversation without end.

It is tempting to imagine the brain as a vast collection of tiny wires carrying messages from one place to another. But it is much more complicated than that.

A single neuron may receive signals from thousands of other neurons. Some signals encourage it to act. Others tell it not to. At every moment, countless cells are influencing one another in an immense, shifting conversation. 

There is no single neuron in your head labelled MEMORY. Nor is there one labelled ME, FEAR, CHILDHOOD, or WHERE THE HELL AM I?

Instead, experiences are represented by patterns of activity across networks of neurons.When you recognise the smell of rain in Singapore, for example, one group of neurons may be processing the smell itself. Others may be connecting it with memories. Others may be involved in emotion. Others may be preparing your body to move. The experience emerges from the interaction of the whole network.

The first great idea for you to grasp is that the brain does not work because individual neurons are clever. It works because neurons are connected.

From simplicity to complexity

This is one of the extraordinary things about the brain. The individual parts are relatively simple.

A neuron receives signals. It responds according to certain rules. It sends signals onwards. Yet from the interaction of billions of these simple cells emerges something unimaginably complicated.

A symphony is not contained in a single violin;  a city is not contained in a single house;  and you are not contained in a single neuron.

You are, in some sense, an ever-changing pattern created by the activity of billions of cells communicating with one another. The neurons themselves are constantly changing their connections and their strength of communication. Experiences alter the network. Learning alters it. Trauma alters it. Repetition alters it.This ability of the brain to change will become increasingly important when we come to memory.

The traveller's parallel

A traveller provides a useful way of thinking about this. Imagine arriving in a completely unfamiliar place. You step off the train. Immediately your senses begin collecting information. Your eyes notice the architecture. Your ears register unfamiliar languages and the sound of traffic. Your nose detects food, drains, incense, diesel.You are trying to work out where you are, where you are going, whether you are lost, whether that man is a taxi driver, and whether the hotel you booked actually exists. No single neuron understands the situation.

Instead, vast networks of neurons are working together. Some process what you see;  some what you hear; some compare the present with memories of previous journeys; some are involved in attention; some in emotion; some in deciding what to do next.

Out of all this electrical and chemical chatter comes a simple conscious experience: I have arrived somewhere new.That is the astonishing journey we are about to explore and we begin with a tiny cell – the neuron. And from that tiny cell, eventually, we will arrive at memory, identity, imagination and perhaps the most mysterious question of all: How can billions of communicating cells produce the experience of being you?

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