The Brain, Biology,
and Behavior

"Imagine yourself smaller than the period at the end of this sentence. Then join me as we enter a bizarre microscopic world. Surrounding us is a tangle of spidery branches, delicate fibers, and transparent globes. As we watch, pulsing waves of electrical energy flash through the fibers, scattering in thousands of directions. Meanwhile, all is bathed in a swirling sea of exotic chemicals. We are indeed in a strange realm. Yet there is beauty here, and mind-bending complexity--for we have just entered that most amazing of all computers, the human brain.

Crack open the fragile shell of the skull and you find, in the truest sense, "worlds within worlds within worlds." The human brain is about the size of a large grapefruit. Weighing a little over 3 pounds, it consists of some 100 billion nerve cells called neurons (New-rons).

Neurons specialize in carrying and processing information. They also activate muscles and glands. Thus, everything you think, do, or feel can be traced back to these tiny cells. The mass of neurons we call the brain allows humans to make music of exquisite beauty, to seek a cure for cancer, or to read a book like this one.

Each neuron in the brain's "enchanted loom" is linked to as many as 10,000 others. This network makes it possible to combine and store an exceedingly large amount of information. In fact, there may be more possible pathways between neurons in a single human brain that there are atoms in the entire universe!

Scientists have long known that the brain is the organ of consciousness and action. But only recently have they been able to demonstrate it directly. To prove the point, researcher Jose Delgado once entered a bullring with a cape and a radio transmitter. The bull charged. Delgado retreated. At the last possible instant the speeding bull stopped short. Why? Because Delgado's radio activated electrodes implanted deep within the bull's brain. These, in turn, stimulated "control centers" that brought the bull to a halt.

Physiological psychology is the study of how the brain and nervous system relate to behavior. It is clear that answers to many age-old questions of mind, consciousness, and knowledge lie buried within the brain (Thompson, 1985). Let us enter this fascinating realm for a closer look at our biological heritage and human potential."

The Brain is an impressive assembly of billions of sensitive cells and nerve fibers. The brain controls vital bodily functions, keeps track of the external world, issues commands to the muscles and glands, responds to current needs, creates the magic of consciousness, and regulates its own behavior --all at the same time. Each of these ^basic needs is met by the action of one or more of the three (3) main brain divisions:

l. Control of vital bodily functions is carried out by the hindbrain (with some assistance from the hypothalamus in the forebrain)

2. Gathering sensory information and issuing motor commands takes place at all three levels of the brain.

3. Response selection, learning, memory, and higher thought processes are controlled by the forebrain, particularly the cortex and association areas.

And yet, in reality much more complex than this, THE BRAIN is also a vast information-processing system. Incoming information scatters to structures all over the brain and converges again as it goes out to muscles and glands. The overall system acts in ways that go far beyond any view that considers only "parts" or "brain centers". One reason for its complexity is its redundancy, or duplication, throughout. The brain may use dozens of areas to carry out a function that any one area could manage alone. Because of such redundancy, the brain has an impressive ability to reorganize itself after injury. Plasticity, however becomes rare after age 10, and neither children nor adults can replace destroyed brain cells, but in the final analysis the brain is both highly vulnerable and amazingly resilient--and it hasn't yet yielded all its secrets.