Two different methods have been used to identify the regions involved in visual perception and visual imagery. First, [[Cerebralfunctional magnetic resonance imaging]] (fMRI) is used to measure [[cerebral blood flow]], which allows researchers to identify the amount of bloodglucose and oxygen travelingbeing toconsumed by a specific part of the brain, with an increase in blood flow providing a measure of brain activity. AnSecond, an [[event related potential]] (ERP) can be used to show the amount of electrical brain activity that is occurring due to a particular stimulus. Researchers have used both methods to determine which areas of the brain are active with different stimuli, and results have supported the dual-coding theory. Other research has been done with [[positron emission tomography]] (PET) scans and [[functional magnetic resonance imaging]] (fMRI) to show that participants had improved memory for spoken words and sentences when paired with an image, imagined or real, and showed increased brain activation to process abstract words not easily paired with an image.
