ABSTRACT
The cerebral cortex consists of the outer regions of the cerebral hemispheres. The rear of the frontal lobe is the motor projection area (motor cortex). The functions of the projection areas were originally discovered by stimulation studies; applying electrical stimuli to the exposed cortex of animals and humans permitted the mapping of motor and sensory projection areas. Areas of cortex close to the projection areas are involved with single sensory or motor functions, while those further from the projection areas coordinate different senses, and sensory-motor functions. The right hemisphere, in most people, is specialized for synthetic functions, such as complex drawing, interpreting maps, and spatial localization. A patient is unable to name an object shown briefly to the right hemisphere, because the right hemisphere cannot communicate with the language areas in the left hemisphere. The effects of brain lesions are not necessarily permanent. Recovery results from one or more of four mechanisms.
