8. The higher cerebral functions

The brain is made up of a phylogenetically primitive part (the limbic system) and a more modern part. The more primitive part is the seat of aggression, emotion and episodic learning. The processes controlled from the modern part include perception, interpretation and association, and planning. Aphasia, agnosia and apraxia are the main disorder groups relevant in this context. The dominant hemisphere (usually the left) has an analytical function, while the non-dominant hemisphere has a more emotional and strategic function. Cortical function disorders cannot always be localized. Both the cortex itself and its internal and external connections can play a role. Disorders of the latter are known as disconnection syndromes. Memory cannot be attributed to any one region. Declarative memory (facts and associations) is associated mainly with the parieto-temporo-occipital regions, while emotional and episodic memory is housed in the more primitive regions, working memory in the basal nuclei. A lot can be learnt about the function of the cerebrum from simple bedside testing.