Читать книгу Abnormal Psychology - William J. Ray - Страница 54

The developing spirit of science during the 1600s began to set the stage for a new breed of scientists to emerge. One of these scientists was an English doctor, Thomas Willis (1621–1675). He was interested in neurology and in fact coined that term along with a number of anatomical terms such as lobe, hemisphere, and corpus striatum. He may also have been the first person to use the word psychology in English.

Willis sought to combine the study of brain structure and function. He suggested that lower-brain structures were responsible for more basic functions of life and that these structures could be found across a variety of vertebrates. On the other hand, those structures located higher in the brain must be involved in more advanced processes seen in higher organisms such as humans. Implicit in this idea is a break with Descartes’ suggestion that animals are only machines.

Figure 1.7 Gray Matter and White Matter in the Brain

Source: CC BY 2.5 John A Beal, PhD Dep’t. of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center Shreveport, http://www.healcentral.org/healapp/showMetadata?metadataId=40566 (Internet Archive of file description page)

By the end of the 1700s, the nervous system had been completely dissected and the major parts described in detail. The brain was seen to be composed of gray matter and white matter, terms we continue to use today (see Figure 1.7). White matter was involved in moving information to and from the gray matter. Today, we have a fuller understanding of brain structure, with the thin outer shell of the brain consisting of cells, which appear to be a darker color and are thus called gray matter. Underlying this are the axons, which transfer information throughout the brain. Their myelin sheaths are lighter in color, and thus these areas are referred to as white matter. Myelin is made up of fats and proteins and wraps around axons like insulation does around electrical cables, resulting in an increased speed of information transmissions.

Also by the 1700s, scientists knew that there was a general pattern in all human brains in how the brain was structured in terms of surface structures or bumps, which were called gyri, and the grooves between them, referred to then and now as sulci and fissures. The present-day terms used to describe parts of the brain also come from Latin, so the lobes of the brain are the frontal lobe, parietal lobe, temporal lobe, and occipital lobe. This can be seen in Figure 1.8.

Scientists of the 1700s also determined that the nervous system had a central division consisting of the brain and spinal cord and a peripheral division consisting of nerves throughout the body (see Figure 1.9).

Figure 1.8 The Lobes of the Brain

Source: Schwartz, Sensation and Perception, Figure 4.7.