title: Left and right basal ganglia and frontal activity during language generation: contributions to lexical, semantic, and phonological processes.
abstract: fMRI was used to determine the frontal, basal ganglia, and thalamic structures engaged by three facets of language generation: lexical status of generated items, the use of semantic vs. phonological information during language generation, and rate of generation. During fMRI, 21 neurologically normal subjects performed four tasks: generation of nonsense syllables given beginning and ending consonant blends, generation of words given a rhyming word, generation of words given a semantic category at a fast rate (matched to the rate of nonsense syllable generation), and generation of words given a semantic category at a slow rate (matched to the rate of generating of rhyming words). Components of a left pre-SMA-dorsal caudate nucleus-ventral anterior thalamic loop were active during word generation from rhyming or category cues but not during nonsense syllable generation. Findings indicate that this loop is involved in retrieving words from pre-existing lexical stores. Relatively diffuse activity in the right basal ganglia (caudate nucleus and putamen) also was found during word-generation tasks but not during nonsense syllable generation. Given the relative absence of right frontal activity during the word generation tasks, we suggest that the right basal ganglia activity serves to suppress right frontal activity, preventing right frontal structures from interfering with language production. Current findings establish roles for the left and the right basal ganglia in word generation. Hypotheses are discussed for future research to help refine our understanding of basal ganglia functions in language generation.
authors.affiliation: McKnight Brain Institute, University of Florida, Gainsville, USA. bcrosson@hp.ufl.edu
authors.forename: Bruce
authors.initials: B
authors.lastname: Crosson
authors.forename: Hope
authors.initials: H
authors.lastname: Benefield
authors.forename: M Allison
authors.initials: MA
authors.lastname: Cato
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Sadek
authors.forename: Anna Bacon
authors.initials: AB
authors.lastname: Moore
authors.forename: Christina E
authors.initials: CE
authors.lastname: Wierenga
authors.forename: Kaundinya
authors.initials: K
authors.lastname: Gopinath
authors.forename: David
authors.initials: D
authors.lastname: Soltysik
authors.forename: Russell M
authors.initials: RM
authors.lastname: Bauer
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Auerbach
authors.forename: Didem
authors.initials: D
authors.lastname: Gökçay
authors.forename: Christiana M
authors.initials: CM
authors.lastname: Leonard
authors.forename: Richard W
authors.initials: RW
authors.lastname: Briggs
mesh_terms: D000293:Adolescent; D000328:Adult; D001479:Basal Ganglia / Q000033:anatomy & histology / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D007807:Language Tests; D008037:Linguistics; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008568:Memory / Q000502:physiology; D010153:Paired-Associate Learning; D013997:Time Factors; D014055:Tomography, Emission-Computed