Learning and memory - Introduction

Learning & Memory

Learning and Memory - Introduction

Albert Einstein said: "the most incomprehensible fact about nature is that it is comprehensible". Indeed, physical phenomena are comprehensible. Weather changes, chemical reactions and molecular structures appear quite complex, but their underlying principles are amazingly simple. All physical phenomena are governed by four fundamental forces - gravity, electromagnetism, strong and weak nuclear forces. Recently, these forces can further be unified by a single theory -- the string theory.

What about the brain? Is its ability of comprehension comprehensible? In the seventeenth century, Isaac Newton had discovered the gravitational law and Robert Boyle had formulated the law for gas property, but human beings were still quite ignorant about physiological systems. William Harvey, a pioneer in blood circulation, told Robert Boyle that it was the valves in the veins which guided him to the next phase of his thinking.

We now know that thoughts are not controlled by blood vessels and sorrow has nothing to do with a "broken heart". They come from our brain -- the only thing which can try to understand itself. With a size smaller than a TV set, our brain contains more than 10 billions of neurons. Each neuron is connected to many (up to thousands) other neurons. The junction between neurons is called the synapse. Brain functions are the results of signal transmission through trillions of synapses.

Since neurons are made up of the same atoms as found in the physical world, it might be possible to explain the brain functions in terms of physical laws. In the past few decades, significant progress has been made toward this goal. The mechanism of learning can be explained at the molecular level. We shall start from the basic information, namely, the generation of nerve impulses and the function of ion channels. You may jump to any topic on your left.