PET evidence of neuroplasticity in adult auditory cortex of XXXX .

@entity2319 @entity1 @entity419 @entity413
Controversy regarding functional reorganization in the adult brain remains. To investigate whether neuroplasticity is present in adults with @entity2319 , we examined the pattern of cerebral @entity413 metabolism on @entity419 brain PET images of postlingually deaf @entity1 by comparing the auditory cortical activation pattern with those of age- and sex-matched healthy control subjects. We also correlated the cerebral @entity413 metabolism in deaf @entity1 with the duration of @entity2319 using statistical parametric mapping. METHODS: In the resting state (eye closed, ears unoccluded in a dark and quiet environment), @entity419 brain PET scans were performed on 9 postlingually deaf @entity1 and 9 age- and sex-matched healthy volunteers. Significant increases and decreases of regional cerebral metabolism in the @entity1 group were estimated by comparing their PET images with those of the healthy volunteers using t statistics at every voxel. To reveal regions in which metabolism was significantly correlated with the duration of @entity2319 , the general linear model with the duration of @entity2319 as a covariate was tested at each voxel. RESULTS: When we compared @entity419 brain PET images of postlingually deaf @entity1 with those of age- and sex-matched healthy control subjects by performing a t test at every voxel, the @entity413 metabolism of deaf @entity1 was significantly (P < 0.001) lower than that of the control subjects in both anterior cingulate gyri (Brodmann area 24 [BA24]) and superior temporal cortices (BA41, BA42) and in the right parahippocampal gyrus. No area showed a significant increase of metabolism in deaf @entity1 with the same threshold. When we correlated @entity413 metabolism of deaf @entity1 with the duration of @entity2319 after total deprivation of hearing capability using a general linear model with the duration of @entity2319 as a covariate at every voxel, metabolism in both anterior cingulate gyri (BA24) and superior temporal cortices (BA41, BA42) showed a significant (P < 0.005) positive correlation with the duration of @entity2319 . CONCLUSION: This study suggests that plasticity is present in adult brains of postlingually deaf @entity1 . In the mature brain, auditory deprivation decreased neuronal activity transiently in primary auditory and auditory-related cortices, and, over time, functional reorganization likely takes place in the auditory cortex. Plasticity was prominent in superior temporal and anterior cingulate gyri in the sensory-deprived mature brain and militated against postimplantation improvement in @entity1 with cochlear implants.
