Broadly speaking, the cerebral cortex is responsible for so-called ‘higher-order’ functions such as thought, voluntary movements, reasoning and perception. One way of accounting for its functions is by means of considering those ascribed to the four lobes:
• frontal lobe: associated with reasoning, planning, parts of speech, voluntary movement, emotions and problem solving. Specific parts of the frontal lobe communicate with areas of the parietal lobe concerned with 3-D perception.
• occipital lobe: associated with ‘higher-order’ visual perception (e.g., depth perception, detection of edges and borders, object recognition). It has two output pathways: the dorsal stream concerned with the visual location of objects and the ventral stream with the identification of objects.
• parietal lobe: associated with movement, orientation, recognition, perception of somatosensory information, and the formation of 3-D representations, in addition to processing information contained in the dorsal stream.
• temporal lobe: associated with the perception and recognition of auditory stimuli, memory and speech. Information from the dorsal stream is fed by the temporal lobe to the hippocampus and associated structures.
A long-standing issue about the functions of the cerebral cortex relates to the degree to which they are deemed to be localised in discrete areas of this structure. At one extreme, intimations of which can be detected in Greek antiquity with Hippocrates (460-377 BP), Plato (427-347 BP),and Galen (129-210), but really stemming from the first half of the 19th century with the phrenology of Franz Josef Gall (1758-1828) and later subjected to case-study observations by Pierre Paul Broca (1824-1880) and to experimental verification by the likes of Gustav Theodor Fritsch (1838-1927) and Eduard Hitzig (1838-1907), support was garnered for the functional localisation hypothesis. One who came to a more intermediate standpoint was Marie-Jean-Pierre Flourens (1794-1867), an opponent of phrenology, who found evidence for localisation of functions in sub-cortical structures such as the cerebellum, but concluded that mental functions were dispersed throughout the whole cerebrum. Without doubt, the most convincing evidence for the hypothesis in the 19th century came with the work of David Ferrier (1843-1928) and his book Functions of the brain (1876), a student of Alexander Bain (1818-1903) who was influenced by the writings of John Hughlings Jackson (1835-1911). While this hypothesis of exact cerebral localisation was challenged by the view of equipotentiality (viz., cortical functions are distributed throughout areas of the cerebral cortex that constitute uniform fields) stressed by Karl Spencer Lashley (1890-1958), it has in recent years gained the ascendancy with the incursion of the notion of modularity into cognitive neuroscience and the increasing sophistication of functional imaging techniques.
See Brain (neuro-) imaging, Cerebral cortex (development), Cerebral disorders, Cerebral cortex (or pallium), Cortical lobes, Dorsal visual pathway (or stream), Double dissociation, Equipotentiality, Inferior parietal lobe (IPL), Modularity, Two visual systems hypothesis, Ventral vIsual pathway (or stream)