Introduction

The central mystery about the brain is simply this: How can a bunch of interconnected cells make each of us what we are — not only our thoughts, memories, and feelings, but our identity. At present, no one can answer this question. Some philosophers think it is not answerable in principle.

I believe we can understand how the brain makes us what we are. This book, while surely not containing the complete answer, points the way to what the answer looks like: In short, the brain is made of neurons, each of which is a complex little computer. Parts of the nervous system make suggestions to the rest of it about what you should do next. Other parts process the sensory inputs you receive and tell the system how things are going so far. Still other parts, particularly those associated with language, make up a running dialog about all of this as it is going on; this is your consciousness.

Those concepts aren’t too difficult to grasp, but people think of neuroscience as hard. And why? Because in order for your nervous system to perform these functions, it takes 100 billion neurons and a quadrillion connections structured over billions of years of evolution and all the human years of development and learning that resulted in who you are and where you are now.

You need to know three things to understand how the nervous system works. The first is how the neurons themselves work. The second is how neurons talk to each other in neural circuits. The third is how neural circuits form a particular set of functional modules in the brain. The particular set of modules that you have make you a human. The content of your specific modules make you unique.

Our nearest animal relative, the chimpanzee, has pretty much the same neurons and neural circuits that you and I do. They even have most of the same modules. We humans have a few extra modules that permit consciousness. Understanding this is what this book is about.

About This Book

Let’s face it. Neuroscience is a complex topic. How could it not be since it deals with the brain, the most complex structure in the known universe. In this book, I explain some very complex ideas and connections in a way that both students enrolled in introductory neuroscience courses and those who are just interested in the topic for fun can understand.

To use and understand this book, you don’t have to know anything about the brain except that you have one. In this book, I cover as much of the basics as possible with simple language and easy-to-understand diagrams, and when you encounter technical terms like anterior cingulate cortex or vestibulospinal reflex, I explain what they mean in plain English.

This book is designed to be modular for the simple reason that I want you to be able to find the information you need. Each chapter is divided into sections, and each section contains information about some topic relevant to neuroscience, such as

  • The key components of the nervous system: neurons and glia
  • How neurons work and what the different kinds of neurons are
  • What systems are involved in planning and executing complex actions
  • The role of the neocortex in processing thoughts

The great thing about this book is that you decide where to start and what to read. It’s a reference you can jump into and out of at will. Just head to the table of contents or the index to find the information you want.

Note: You can use this book as a supplemental text in many undergraduate courses because I discuss the neuron and brain function as a system. Typical undergraduate perception courses, for example, give short (and usually unsatisfactory) introductions to neurons and neural processing and little if any coverage of cognition. Cognitive psychology and neuroscience courses typically cover cognition well but often don’t ground cognition at the level of neurons. Behavioral neuroscience courses sometimes ignore cognition and neurophysiology almost altogether while doing a decent job explaining heuristics and phenomenology of behavior and learning. You can also use this book as an adjunct to graduate or health profession courses where the nervous system or mental illnesses or disorders are mentioned but little explicit coverage is given of the nervous system and the brain.

Within this book, you may note that some web addresses break across two lines of text. If you’re reading this book in print and want to visit one of these web pages, simply key in the web address exactly as it’s noted in the text, pretending as though the line break doesn’t exist. If you’re reading this as an e-book, you’ve got it easy — just click the web address to be taken directly to the web page.

Foolish Assumptions

In writing this book, I made some assumptions about you. To wit:

  • You’re not a professional neuroscientist or neurosurgeon but may be a beginning student in this field. (If you notice that your neurosurgeon thumbing through a copy of this book before removing parts of your brain, you might want to get a second opinion.)
  • You’re taking a course that relates to brain function, cognition, or behavior and feel that you would do better if you had a firm grasp of how the nervous system and its components work.
  • You want information in easy-to-access and easy-to-understand chunks, and if a little humor can be thrown in, all the better!

If you see yourself in the preceding points, then you have the right book in your hands.

Icons Used in This Book

The icons in this book help you find particular kinds of information. They include the following:

tip Looking at things a little differently or thinking of them in a new way can make potentially confusing concepts easier to understand. Look for this icon to find these “think of it this way” types of discussions.

remember This icon appears next to key concepts and general principles that you’ll want to remember.

technicalstuff In a subject as complicated as neuroscience, it’s inevitable that some discussions will be very technical. Fortunately for you, you don’t need to know the detailed whys and wherefores, but I include this info anyway for those who are voraciously curious or gluttons for punishment. Read or skip paragraphs beside this icon at will.

Beyond This Book

In addition to the material in the print or e-book you’re reading right now, this product also comes with some access-anywhere material on the web. The Cheat Sheet fills you in on types and function of cells in the central nervous system, the role of the neocortex, the left and right hemispheres of the brain, the brain’s four lobes, and more. To get this Cheat Sheet, simply go to www.dummies.com and type Neuroscience For Dummies Cheat Sheet in the Search box.

Where to Go from Here

Finally, the purpose of this book is to get you up to speed fast in understanding neurons and the nervous system, particularly the brain, but there are many important neuroscience topics that fall well beyond the scope of this book. Here’s just a sampling: intra-neuronal metabolism and second messenger cascades, association of neurological deficits with lesions in specific tracts and nuclei, traditional learning theory, and modern genetics. You can find detailed discussion of most of these subjects in Kandel, Schwartz, and Jessel’s Principles of Neural Science, 4th Edition (McGraw-Hill, 2000), the bible of neuroscience books.