The differing roles of the frontal cortex in fluency tests
Open Access
- 4 June 2012
- journal article
- research article
- Published by Oxford University Press (OUP) in Brain
- Vol. 135 (7), 2202-2214
- https://doi.org/10.1093/brain/aws142
Abstract
Fluency tasks have been widely used to tap the voluntary generation of responses. The anatomical correlates of fluency tasks and their sensitivity and specificity have been hotly debated. However, investigation of the cognitive processes involved in voluntary generation of responses and whether generation is supported by a common, general process (e.g. fluid intelligence) or specific cognitive processes underpinned by particular frontal regions has rarely been addressed. This study investigates a range of verbal and non-verbal fluency tasks in patients with unselected focal frontal (n = 47) and posterior (n = 20) lesions. Patients and controls (n = 35) matched for education, age and sex were administered fluency tasks including word (phonemic/semantic), design, gesture and ideational fluency as well as background cognitive tests. Lesions were analysed by standard anterior/posterior and left/right frontal subdivisions as well as a finer-grained frontal localization method. Thus, patients with right and left lateral lesions were compared to patients with superior medial lesions. The results show that all eight fluency tasks are sensitive to frontal lobe damage although only the phonemic word and design fluency tasks were specific to the frontal region. Superior medial patients were the only group to be impaired on all eight fluency tasks, relative to controls, consistent with an energization deficit. The most marked fluency deficits for lateral patients were along material specific lines (i.e. left—phonemic and right—design). Phonemic word fluency that requires greater selection was most severely impaired following left inferior frontal damage. Overall, our results support the notion that frontal functions comprise a set of specialized cognitive processes, supported by distinct frontal regions.Keywords
This publication has 53 references indexed in Scilit:
- Conceptual proposition selection and the LIFG: Neuropsychological evidence from a focal frontal groupNeuropsychologia, 2010
- Executive function and fluid intelligence after frontal lobe lesionsBrain, 2009
- Localizing interference during naming: Convergent neuroimaging and neuropsychological evidence for the function of Broca's areaProceedings of the National Academy of Sciences of the United States of America, 2009
- Mapping task switching in frontal cortex through neuropsychological group studiesFrontiers in Neuroscience, 2008
- Is there a dysexecutive syndrome?Philosophical Transactions Of The Royal Society B-Biological Sciences, 2007
- Role of the left inferior frontal gyrus in covert word retrieval: Neural correlates of switching during verbal fluencyNeuropsychologia, 2006
- A failure of high level verbal response selection in progressive dynamic aphasiaCognitive Neuropsychology, 2005
- A Meta-Analytic Review of Verbal Fluency Performance Following Focal Cortical Lesions.Neuropsychology, 2004
- Single Word Comprehension: A Concrete and Abstract Word Synonym TestNeuropsychological Rehabilitation, 1998
- SEMANTIC DEMENTIABrain, 1992