Functions of the Four Lobes: The functions of the four lobes of the cerebral cortex are to control motor, somatosensory, visual and auditory processing in humans.
The principle function of the frontal lobe is the control of movement. The primary motor cortex, an important arch of tissue, is located at the back of the frontal lobe and runs laterally over the top of the brain. This area directs the body's muscles.The frontal lobe is also related to more complex behaviours. Its functions seem to be related to planning, changing strategies, self-awareness, attention to emotionally related stimuli and spontaneity of behaviour. Patients with frontal lobe damage demonstrate: slowing of thoughts and behaviour,getting 'stuck' on tasks and repeating the same wrong answers over and over, i.e. they have difficulty changing strategies,loss of self-awareness,changes in emotional reactions;they react with indifference to events that normally elicit an emotional response,deficiencies in planning,loss of spontaneity.
Parietal Lobe: This lobe is located just above the occipital lobe. The principal sensory function of the parietal lobe is somatosensory perception, where bodily sensations are registered. The lower parts of the parietal lobe are concerned with visually and acoustically related functions. The parietal lobe is also very important in our perception of space and in monitoring the body's position in space.
Damage to the left parietal lobe can result in alexia, the loss of the ability to read, or agraphia, the loss of the ability to write. A person's ability to draw is also impaired when the parietal lobe is damaged.
Occipital Lobe: This lobe is located at the back of the head. The primary function of the occipital lobe is seeing. Visual input ultimately reaches the occipital lobe of the cortex where cells communicate with one another extensively in a rich processing network.
Damage to the primary visual cortex of the occipital lobe produces blindness. Damage to the visual association cortex (which includes parts of the parietal and temporal lobes, as well as the occipital lobe) of the left hemisphere affects the ability to recognise details of a visual scene. However, damage to the visual association cortex of the right hemisphere affects the visual recognition of familiar objects.
Frontal Lobe Damage: Damage to the back portions of the frontal lobe also leads to problems in the control of eye movements.
Broca's area is located just below and ahead of the primary motor cortex. It is essential for the production of speech. It is a language area related to grammar and pronunciation. Damage to this region results in a form of aphasia (impaired language ability), characterised by slow, laboured, difficult speech that lacks grammatical structure. The person is able to read and understand other people's speech but have great difficulty speaking or writing themselves.
Temporal Lobe: This lobe is located at each side of the brain, below the parietal lobe. The principal sensory function of the temporal lobe is hearing, however, this lobe is also involved in vision, memory and factors of personality and social behaviour.
One of the most important language areas of the brain is a region of the auditory association cortex on the left side of the brain called Wernicke's area. This area is necessary for the identification of spoken words. Damage to Wernicke's area results in Wernicke's aphasia, where a person finds it difficult to comprehend speech and language.