with stuttering. In general, during stuttering, cerebral activities change dramatically in comparison to silent rest or fluent speech between people who stutter and people who do not. There is evidence that people who stutter activate motor programs before the articulatory or linguistic processing is initiated. Brain imaging studies have primarily been focused on adults. However, the neurological abnormalities found in adults does not determine whether childhood stuttering caused these abnormalities or whether the abnormalities cause stuttering. Studies utilizing positron emission tomography (PET) have found during tasks that invoke disfluent speech, people who stutter show hypoactivity in cortical areas associated with language processing, such as Broca's area, but hyperactivity in areas associated with motor function. One such study that evaluated the stutter period found that there was overactivation in the cerebrum and cerebellum, and relative deactivation of the left hemisphere auditory areas and frontal temporal regions. Functional magnetic resonance imaging (fMRI) has found abnormal activation in the right frontal operculum (RFO), which is an area associated with time-estimation tasks, occasionally incorporated in complex speech. Researchers have explored temporal cortical activations by utilizing magnetoencephalography (MEG). In single-word-recognition tasks, people who did not stutter showed cortical activation first in occipital areas, then in left inferior-frontal regions such as Broca's area, and finally, in motor and premotor cortices. The stutterers also first had cortical activation in the occipital areas but the left inferior-frontal regions were activated only after the motor and premotor cortices were activated. During speech production, people who stutter show overactivity in the anterior insula, cerebellum and bilateral midbrain. They show underactivity in the ventral premotor, Rolandic opercular and sensorimotor cortex bilaterally and Heschl's gyrus in the left hemisphere. Additionally, speech production yields underactivity in cortical motor and premotor areas. Abnormal lateralization Much evidence from neuroimaging techniques has supported the theory that the right hemisphere of people who stutter interferes with left-hemisphere speech production. Adults who stutter have anatomical differences in gyri within the perisylvian frontotemporal areas. A large amount of white matter is found in the right hemisphere of the brain, including the region of the superior temporal gyrus. This was discovered using voxel-based morphometry (VBM). On the other hand, lesser amounts of white matter are found in the left inferior arcuate fasciculus connecting the temporal and frontal areas in stuttering adults. Results have shown that there is less coordination between the speech motor and planning regions in the brain's left