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1.3.4 Studying the Brain: Sources of Evidence for the Modular Brain
Where are some sources of evidence for brain modularity?
Studies of patients who have experienced brain lesions (structural changes in the brain) due to injury or disease reveal brain modularity. Many patients exhibit the same behavioural changes or deficits after suffering a brain lesion that occurs in the same physical area of the brain, often due to a stroke. Studies of the effects of injuries and diseases occurring in different parts of the brain have disclosed a number of modules.
Another source is measurement and observation of brain activity using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). These techniques reveal which specific parts of the brain are active during the performance of a mental or physical task. If, in many individuals, the same specific areas “light up” during the performance of the same task, it indicates a module or modules at work.
Some other information sources that scientists in a variety of specialties use to study the functioning of the brain’s mental organs are:
- Observed effects of abnormalities in specific genes that implicate certain modules, such as the FOXP2 gene and language (discussed a bit later in this section)
- Observed effects of taking drugs that act on specific modules
- Optical and aural illusions that trigger conflicts between modules
- Studies of behaviour and abilities of newborns and pre-lingual infants—particularly useful in revealing the inborn, adaptive aspects of music
- Comparative studies of identical twins, fraternal twins, biological siblings, and adopted siblings