Positron emission tomography
Positron emission tomography (PET) and functional magnetic resonance (fMRI) allow cognitive neuroscientists to explore different hypotheses concerning the neural network organization of semantic memory. By using these neuroimaging techniques researchers can observe the brain activity of participants while they perform cognitive tasks. These tasks can include, but are not limited to, naming objects, deciding if two stimuli belong in the same object category, or matching pictures to their written or spoken names.