It is helpful to view the |brain| in a frontal cut-away, which illustrates the locations of its structures with respect to the right and left hemispheres. Research has demonstrated that the left and right hemispheres are not quite identical and, in fact, they seem to control different aspects of thought. The left |brain| is responsible for much of the higher thought processes which are related with analysis and speech, whereas the right hemisphere appears to be responsible for more aesthetic thought processes, such as imagination and visual pattern recognition. Hence, one who is particularly good at mathematics, logic, and science often is said to be "left-brain" influenced. Similarly, artists, musicians, and writers are considered to be "right-brain" influenced. The |brain| itself, of course, is the primary component of the nervous system, occupying the cranial cavity. Without its outermost protective membrane, the |dura mater|, the |brain| weighs an average of three pounds (about 1.4 kilograms), comprising about 97% of the entire central nervous system. The |brain| is connected to the upper end of the |spinal cord| (which connects through the |foramen magnum| of the |skull|) and is responsible for issuing ~nerve~ impulses, processing ~nerve~ impulse data, and engaging in the higher order thought processes. The |brain| is divided into three parts: the large |cerebrum|, the smaller |cerebellum|, and the brainstem leading to the |spinal cord|. The brainstem is also descriptively divided into the |medulla| oblongata, the midbrain, and the |pons|.
