Different types of sensory information are processed in different parts of the nervous system, which sends out appropriate response signals. Complex information, such as data about music and emotion, is processed in the cerebral cortex, which is known as the “higher” part of the brain. Some specialized functions, such as the interpretation of language, are processed mainly in one side of the brain, the “dominant hemisphere”. The left hemisphere is dominant in more than 9 out of 10 people.
Neuroscientists can now pinpoint those parts of the brain’s cortex that process nerve impulses concerned with higher human functions, such as intellect and memory. Areas of the cortex that are mainly concerned with detecting nerve impulses are known as primary areas; the parts that are concerned with analysing impulses are known as association areas.
Each side of the brain has its own motor and sensory cortices, which control movement and sense touch in the opposite side of the body. Movement signals are processed by a particular region at the top of the cerebrum in the motor cortex. An adjacent area, known as the sensory cortex, processes touch signals. Movements that involve great complexity or body parts that are extremely sensitive to touch are allocated a larger proportion of motor or sensory cortex. In general, those parts of the body capable of complex movement are also highly sensitive to touch.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.