The Future of the Mind Read Online Free PDF

frontal lobe, is where most rational thought is processed. The information you are reading right now is being processed in your prefrontal cortex. Damage to this area can impair your ability to plan or contemplatethe future, as in the case of Phineas Gage. This is the region where information from our senses is evaluated and a future course of action is carried out.

    Figure 2 . The four lobes of the neocortex of the brain are responsible for different, though related, functions. ( illustration credit 1.2 )
    The parietal lobe is located at the top of our brains. The right hemisphere controls sensory attention and body image; the left hemisphere controls skilled movements and some aspects of language. Damage to this area can cause many problems, such as difficulty in locating parts of your own body.
    The occipital lobe is located at the very back of the brain and processes visual information from the eyes. Damage to this area can cause blindness and visual impairment.
    The temporal lobe controls language (on the left side only), as well as the visual recognition of faces and certain emotional feelings. Damage to this lobe can leave us speechless or without the ability to recognize familiar faces.
    THE EVOLVING BRAIN
    When you look at other organs of the body, such as our muscles, bones, and lungs, there seems to be an obvious rhyme and reason to them that we can immediately see. But the structure of the brain might seem slapped together in a rather chaotic fashion. In fact, trying to map the brain has often been called “cartography for fools.”
    To make sense of the seemingly random structure of the brain, in 1967 Dr. Paul MacLean of the National Institute of Mental Health applied Charles Darwin’s theory of evolution to the brain. He divided the brain into three parts. (Since then, studies have shown that there are refinements to this model, but we will use it as a rough organizing principle to explain the overall structure of the brain.) First, he noticed that the back and center part of our brains, containing the brain stem, cerebellum, and basal ganglia, are almost identical to the brains of reptiles. Known as the “reptilian brain,” these are the oldest structures of the brain, governing basic animal functions such as balance, breathing, digestion, heartbeat, and blood pressure. They also control behaviors such as fighting, hunting, mating, and territoriality, which are necessary for survival and reproduction. The reptilian brain can be traced back about 500 million years. (See Figure 3 .)
    But as we evolved from reptiles to mammals, the brain also became more complex, evolving outward and creating entirely new structures. Here weencounter the “mammalian brain,” or the limbic system, which is located near the center of the brain, surrounding parts of the reptilian brain. The limbic system is prominent among animals living in social groups, such as the apes. It also contains structures that are involved in emotions. Since the dynamics of social groups can be quite complex, the limbic system is essential in sorting out potential enemies, allies, and rivals.

    Figure 3 . The evolutionary history of the brain, with the reptilian brain, the limbic system (the mammalian brain), and the neocortex (the human brain). Roughly speaking, one can argue that the path of our brain’s evolution passed from the reptilian brain to the mammalian brain to the human brain. ( illustration credit 1.3 )
    The different parts of the limbic system that control behaviors crucial for social animals are:
    •  The hippocampus. This is the gateway to memory, where short-term memories are processed into long-term memories. Its name means“seahorse,” which describes its strange shape. Damage here will destroy the ability to make new long-term memories. You are left a prisoner of the present.
    •  The amygdala. This is the seat of emotions, especially fear, where emotions are first registered and generated. Its name means