Cortical activations for covert and overt picture naming on fMRI / 中国医学影像技术

ABSTRACT

Objective To investigate cortical activation patterns for covert and overt picture naming with functional magnetic resonance imaging (fMRI). Methods fMRI data were collected on 24-27 years old volunteers during performance of covert and overt picture naming. After statistical postprocessing analysis, head movement data were compared across tasks and average neural activation maps were available for both tasks. Results Mean and maximal translations of head movement in covert picture naming were less than those in overt picture naming, but the difference has no statistical significance (P=0.23). It was shown that covert picture naming involved an orchestration of bilateral occipital gyri and cerebellums, bilateral supplementary motor area, postcentral gyri, inferior frontal gyrus and anterior cingulate cortex. Activations in overt picture naming included those in covert naming (but more intensive), bilateral precentral gyri and posterior superior temporal gyri, left anterior superior temporal gyrus, bilateral thalamus, basal ganglia, and left insula. Conclusion Covert and overt picture naming are two different tasks involving different neural processing networks and levels. They can not be taken as substitutes for each other.