The purpose of this protocol is to localize the neural regions and systems mediating the forms of knowledge representations hypothesized by the principal investigator to be stored in the human prefontal cortex. Utilizing experimental neuropsychological tasks during functional MRI on healthy, adult volunteers, we will investigate hypotheses regarding the role of the dorsolateral prefrontal cortex in mathematical cognition in a population of normal controls recruited among college and graduate students. We will also attempt to determine the relationship of mathematical cognition between non-frontal neural structures, such as left parietal lobe, and frontal neural structures involved in mechanistic plans, actions and mental sets. The data collected will consist of behavioral measures of cognitive performance and corresponding fMRI images. The data that we collect in this protocol will be of value in identifying a set of neural regions and distributed networks mediating the forms of knowledge representation stored in the prefrontal cortex. We will also use the data obtained in these studies to constrain theories of frontal lobe function and to provide evidence for the role of specific frontal cortex sectors in specific cognitive functions.
INCLUSION CRITERIA: Graduate students and undergraduate students who have completed two years of college. They also must have taken at least one college course in Integral Calculus. Age range: 19-40. Right-handedness (some left-handed subjects may be recruited for preliminary behavioral studies). EXCLUSION CRITERIA: Individuals with a neurological or psychiatric history or medical condition that would constrain interpretation of their performance during functional neuroimaging studies will be excluded. Individuals with contraindications to exposure to high magnetic field.