Brain Fitness for Women. Sondra Kornblatt

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       Chapter 2

      Brain Basics

      Does Your Brain Know It's a Girl?

      With modern parts atop old ones, the brain is like an iPod built around an eight-track cassette player.

      Sharon Begley, journalist

      If a woman has to choose between catching a fly ball and saving an infant's life, she will chose to save the infant's life without even considering if there are men on base.

      Dave Barry, humorist

      By the time my daughter was eight, she was pretty blasé when people mistook her for a boy, which was a fairly common occurrence. After all, my daughter usually wore a baseball (not softball) uniform or comfortable clothes from the boys’ department—not pink or purple clothes with short, useless sleeves and lace. Her hair was short, her style was brisk, and it was perfectly logical that sales clerks, strangers in the park, and even new parents at school would assume she was a boy.

      Even though it wasn't easy for strangers to tell that my daughter was a girl, she knew she was one. And even though it's not easy to tell if a young brain (in a lab, without the body) belongs to a boy or girl, the brain knows what it is—at least as far as basic reproduction. Beyond that, there are plenty of questions and plenty of opinions about whether our actions are hardwired into the gender of the brain.

      We'll look at the brain and sex in this chapter and the next, after we understand a little bit about the miracle everyone has inside their skull.

      The Basic Brain

      The brain is the most complex structure on earth.² The physical brain—consisting of mostly water (about 78%), plus fats, proteins, and carbohydrates—can sense the outside and inner world, create thoughts and feelings, keep you breathing and pumping blood, and discover new ways to relate to the world. The brain is mind-boggling.

      To understand the components of the awesome brain, let's create a model using your hands. Make two fists, touching the first knuckles together and keeping your thumbs parallel. Your combined fists are about the size of a brain.

      Now, imagine that between your fists is a ball of bread dough about the size of a tennis ball; inside the dough are two shelled almonds and two shelled walnuts, one of each within the dough in either fist. This dough is your limbic system, the oldest part of your brain; it supports basic brain functions, including emotion, behavior, and long-term memory. The two almonds together are your amygdalae, which govern your emotions and fight-or-flight fear response. The two walnuts represent your thalamus, the center for sensory and motor functions.

      Now bend your arms so your elbows point to the floor and your knuckles point to the sky. If someone put a pencil between your arms, that pencil would be your spinal cord, and your wrists would be your brain stem. The brain stem manages basic body functions, such as heart rate and consciousness (being awake or sleepy). Combine the limbic system and brain stem (the dough ball and your wrists), and you have a pretty functional brain system for animals.

      But we're missing the cerebellum, which you can imagine as a big blob of dough squeezed out of the back, or pinky side, of your hand, by your wrist. The cerebellum is called a “little brain.” It's like a little computer that connects and coordinates motor control, cognitive functions such as attention and language, and probably some emotional responses such as fear and pleasure. The cerebellum connects to the more complex cerebral cortex on top of the brain.³

      Your combined fists represent the two hemispheres of the cerebrum and their fissures (folds that increase the surface area of the brain). The thumb side is the front of the brain: the frontal lobes responsible for reasoning, motivation, and other higher brain functions that allow you to read, drive, and play Wii Fit. The middle fingers are the parietal lobes, which are responsible for touch, movement, and orientation. The backs of the hands (nearest the ears in a person, if the brain were in a head) are the temporal lobes, responsible for auditory stimuli, memory, and speech. Finally, the pinky fingers are the occipital lobes, responsible for visual processing.⁴