BRAIN ACTIVATION MODULATED BY SENTENCE COMPREHENSION

The comprehension of visually presented sentences produces brain activ ation that increases with the linguistic complexity of the sentence. T he volume of neural tissue activated (number of voxels) during sentenc e comprehension was measured with echo-planar functional magnetic reso nance imaging. The modulation of the volume of activation by sentence complexity was observed In a network of lour areas: the classical left -hemisphere language areas (the left laterosuperior temporal cortex, o r Wernicke's area, and the left inferior frontal gyrus, or Broca's are a) and their homologous right-hemisphere areas, although the right are as had much smaller volumes of activation than did the left areas. The se findings generally indicate that the amount of neural activity that a given cognitive process engenders is dependent on the computational demand that the task imposes.