Christopher M McKinney | PubMed Health

PubMed2006

Frontal cortex functional connectivity changes during sound categorization.

Using functional connectivity analysis of functional magnetic resonance imaging data, we investigated the role of the inferior frontal gyrus in categorization of simple sounds. We found stronger functional connectivity between left inferior frontal gyrus and auditory processing areas in the temporal cortex during categorization of speech (vowels, syllables) and nonspeech (tones, combinations of tones and sweeps) sounds relative to an auditory discrimination task; the hemispheric lateralization varied depending on the speech-like properties of the sounds. Our results attest to the importance of interactions between temporal cortex and left inferior frontal gyrus in sound categorization. Further, we found different functional connectivity patterns between left inferior frontal gyrus and other brain regions implicated in categorization of syllables compared with other stimuli, reflecting the greater facility for categorization of syllables.

Acoustic Stimulation↗

PubMed2003

Developmental aspects of language processing: fMRI of verbal fluency in children and adults.

We examined developmental differences, in location and extent of fMRI language activation maps, between adults and children while performing a semantic fluency task. We studied 29 adults and 16 children with echo planar imaging BOLD fMRI at 1.5 T using covert semantic verbal fluency (generation of words to categories compared to rest) using a block design. Post task testing was administered to assess performance. Individual data were analyzed with an a priori region of interest approach from t maps (t = 4) and asymmetry indices (AI). Group studies were analyzed using SPM 99 (Wellcome, UK; fixed effect, corrected P < 0.0001). We found no significant differences in location or laterality of activation between adults and children for a semantic verbal fluency task. Adults activated more pixels than children in left inferior frontal gyrus and left middle frontal gyrus, but AIs were the similar across ages (r(2) < 0.09). Extent or laterality of activation was not affected by performance (r(2) < 0.15). The brain areas that process semantic verbal fluency are similar in children and adults. The laterality of activation does not change appreciably with age and appears to be strongly lateralized by age 7 years.

Adolescent↗