Language affects patterns of brain activation associated with perceptual decision.

Well over half a century ago, Benjamin Lee Whorf [Carroll JB (1956) Language, Thought, and Reality: Selected Writings of Benjamin Lee Whorf (MIT Press, Cambridge, MA)] proposed that language affects perception and thought and is used to segment nature, a hypothesis that has since been tested by linguistic and behavioral studies. Although clear Whorfian effects have been found, it has not yet been demonstrated that language influences brain activity associated with perception and/or immediate postperceptual processes (referred hereafter as "perceptual decision"). Here, by using functional magnetic resonance imaging, we show that brain regions mediating language processes participate in neural networks activated by perceptual decision. When subjects performed a perceptual discrimination task on easy-to-name and hard-to-name colored squares, largely overlapping cortical regions were identified, which included areas of the occipital cortex critical for color vision and regions in the bilateral frontal gyrus. Crucially, however, in comparison with hard-to-name colored squares, perceptual discrimination of easy-to-name colors evoked stronger activation in the left posterior superior temporal gyrus and inferior parietal lobule, two regions responsible for word-finding processes, as demonstrated by a localizer experiment that uses an explicit color patch naming task. This finding suggests that the language-processing areas of the brain are directly involved in visual perceptual decision, thus providing neuroimaging support for the Whorf hypothesis.

Mapping brain structure in attention deficit-hyperactivity disorder: a voxel-based MRI study of regional grey and white matter volume.

The neuroanatomical basis of attention deficit-hyperactivity disorder (ADHD) is postulated to involve brain circuitry responsible for attention and executive function. Relatively new automated methods of MRI analysis allow rapid examination of each volume element (voxel) of whole brain, therefore we planned a comprehensive quantitative examination of brain anatomy in children with ADHD using voxel-based methods. We aimed to quantify whole brain, global tissue class and regional grey and white matter volume differences in 28 male children with ADHD and 31 closely matched controls. Since ADHD is often complicated by comorbid oppositional defiant disorder (ODD) and conduct disorder (CD), we also conducted post-hoc analyses of subgroups of children with ADHD with and without these comorbidities. Significant regional deficits in ADHD were observed within a predominantly right-sided frontal-pallidal-parietal grey matter network and bilateral white matter tracts. Post-hoc comparisons suggested that comorbid ODD or CD did not greatly alter the extent of regional pathology in ADHD. The exceptions being cerebellar and striatal volume deficits which were significantly greater in children with ADHD plus comorbidities, but not those with ADHD alone, compared to controls. Overall, restricted structural brain abnormalities caused by ADHD were localized to brain systems known to be necessary for attention and executive function.