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Introduction

Life existed for a long time on earth before human intelligence. Does our planet just happen to be the only one whose conditions make life possible? Or are we one of billions of planets that sustain life? If little green men in flying saucers showed up, we could ask them the answer. But failing that, and without any conclusive evidence, we don’t really know.

The data we do have that we can examine is that life originated at least once here on earth very shortly after conditions appeared to be suitable to support it. More than three billion years after that, we humans appeared as a result of an almost uncountable number of life cycles, mutations, and reproductions.

This book is about the essential essence of humans as an intelligent life form — the nervous system. We can and do ask many questions about the nervous system, but here are three of the big ones:

 What does our nervous system have in common with that of other animals?

 How is our nervous system different from that of other animals?

 What differences between humans are associated with differences in their nervous systems?

Neurobiologists have some answers to all three of these questions. We know that neurons are specialized cells with some functions specific to neurons, and others similar to most other cells on earth. We also know that nervous systems have similar organizational themes and methods of communication across all animal species. On the other hand, the nervous systems of mammals and primates are vastly more complicated than those of invertebrates and even of cold-blooded vertebrates. Finally, we know that small genetic differences and life experiences can produce significant changes in the behavior of identical twins that otherwise have almost identical brains.

This book attempts to explain in ordinary language how neurons work, how neurons make nervous systems, and how nervous systems produce intelligence and complex behavior.

About This Book

This book starts with basic concepts and builds off of them. It first discusses cells and their origin and functions, then deals with basic brain anatomy made from those cells, and finally describes specialized systems for sensation, movement, and cognition.

The way this book is organized allows you to find the information you need quickly, whether you want to look up information on a neural dysfunction of a friend or relative who has Alzheimer’s or Parkinson’s diseases or you want to find out what the brain’s thalamus actually does.

Besides being a resource for any non-scientist inquisitive about the brain and nervous system, this book may be a useful accompanying text for students in undergraduate neurobiology courses because it’s both modular and functional. For example, many books talk about brain anatomy using massively long lists of obscurely named brain nuclei and tracts, but they don’t try to help you understand all these components as a functional system. Perception and behavioral neuroscience courses often neglect important aspects of cognitive processing, while cognitive science texts often give you little information about how neural activity actually supports cognition. This book is different. This book uses plain language and some very simple diagrams to show how important parts of the brain and nervous system function.

Sidebars (text in gray boxes) and anything marked with a Technical Stuff icon are skippable. Also, within this book, you may notice some web addresses breaking across two lines of text. If you’re reading this book in print and you 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

As I wrote this book, I made some assumptions about you, the reader:

 You may be looking for information about a neurological disease or dysfunction, possibly affecting someone you know. You want access this information quickly in easy-to-understand chunks.

 You may be taking a college or professional course that covers some aspect of brain function, but the course or the text for the course doesn’t provide enough background information.

 You may be a beginning student in neuroscience, neurology, or neurosurgery who has already learned what’s in this book but you need to look up the basics quickly, maybe to explain it to a layperson. (Warning: If your patients notice you rifling through a copy of this book before recommending treatment options, they might request a second opinion.)

Icons Used in This Book

I use icons in this book to help you find specific kinds of information. They include the following:

Anything marked with a Tip icon is a piece of information about an area of neurobiology that’s often misunderstood or easily confused.

The Remember icon highlights key concepts and principles that you need to remember to understand other areas of neurobiology.

The Research icon is about key studies that led to our current understanding of neurobiology. Sometimes pieces of research are just beautiful in their own right for their elegance and simplicity. Research info bits are nice to drop in conversations at cocktail parties — if you party with people nerdy enough to know a fair amount of neurobiology, at least.

The Technical Stuff icon is about a recent or surprising finding that is not necessarily crucial to understand the chapter but is interesting or counterintuitive in its own right. You can skip these paragraphs and get by just fine, but you may miss some of the more interesting products of research.

Beyond the 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 goodies on the web. Check out the free Cheat Sheet at www.dummies.com/cheatsheet/neurobiology for interesting information on whether paralysis can be cured, whether the mind can be downloaded, whether cyborgs are possible, and more.

Also, check out www.dummies.com/extras/neurobiology for articles on everything from where consciousness exists in the brain to how vision can be restored to the blind.

Where to Go from Here

You can start reading this book anywhere — you don’t have to read it in order from beginning to end. Still, Chapter 1 is a great place to start if you’re looking for an introduction to neurobiology. For more on common diseases and disorders, turn to Part IV. And if you’re short on time, Chapters 19 and 20 pack a powerful punch in not many pages.

I’m always interested in hearing from readers, so whether you find an error or you’d like to make any other comments about this book, feel free to contact me at amthorfr@gmail.com.