Association areas produce a meaningful perceptual experience of the world, enable us to interact effectively, and support abstract thinking and language. The parietal, temporal, and occipital lobes, all located in the posterior part of the cortex, organize sensory information into a coherent perceptual model of our environment centered on our body image. The frontal lobe or prefrontal association complex is involved in planning actions and movement, as well as abstract thought. 

Language abilities are localized in the left hemisphere in Broca's area for language expression and Wernicke's area for language reception. The association areas are organized as distributed networks, and each network connects areas distributed across widely spaced regions of the cortex. Distinct networks are positioned adjacent to one another, yielding a complex series of interwoven networks. In humans, association networks are particularly important to language function.

The processes of language expression and reception occur in areas other than just the perisylvian structures such as the prefrontal lobe, basal ganglia, cerebellum, pons, caudate nucleus, and others. The association areas integrate information from different receptors or sensory areas and relate the information to past experiences. Then the brain makes a decision and sends nerve impulses to the motor areas to elicit responses.

Methods of Brain Function Analysis

Behavioral and neuroscientific methods are used to get a better understanding of how our brain influences the way we think, feel, and act. Many different methods help us analyze the brain and give an overview of the relationship between brain and behavior. This promotes understanding of the ways in which associations are made by multiple brain regions, allowing the appropriate responses to occur in a given situation. Well-known techniques are EEG (electroencephalography), which records the brain's electrical activity, and fMRI (functional magnetic resonance imaging) , which tells us more about brain functions. Other methods, such as the lesion method, are not as well-known, but still very influential in modern neuroscientific research.

Cortical Areas of the Brain

Locations of brain areas historically associated with language processing. Associated cortical regions involved in vision, touch sensation, and non-speech movement are also shown.

This diagram depicts the cortical areas of the brain, including motor areas (primary motor cortex, motor association area, frontal eye field); prefrontal cortex (Broca's area); general interpretation area (primary visual cortex, visual association area, primary auditory cortex, auditory association area); sensory areas and related association areas (primary somatosensory cortex, sensory association area, Wernicke's area).

In the lesion method, patients with brain damage are examined to determine which brain structures were damaged and to what extent this influences the patient's behavior. The concept of the lesion method is based on the idea of finding a correlation between a specific brain area and an occurring behavior. From experiences and research observations, it can be concluded that damage to part of the brain causes behavioral changes or interferes in performing a specific task. 

For example, a patient with a lesion in the parietal-temporal-occipital association area has an agraphia, which means he is unable to write although he has no deficits in motor skills. Consequently, researchers deduce that if structure X is damaged and changes in behavior Y occur, X has a relation to Y.