JOURNAL ARTICLE

Disconnection's renaissance takes shape: Formal incorporation in group-level lesion studies

David Rudrauf, Sonya Mehta, Thomas J Grabowski
Cortex; a Journal Devoted to the Study of the Nervous System and Behavior 2008, 44 (8): 1084-96
18625495
Group-level voxelwise statistical analyses of lesion-deficit relationships have been used to implicate brain structures critical for specific aspects of human cognition and behavior. Current approaches fail to account for the role of fiber tract disruptions in causing deficit, and confound cortical damage with damage to fibers of passage. Here, we develop a framework, Generalized Lesion-Symptom Mapping (GLSM), to integrate fiber tract information from DTI-based tractographic atlases in tractwise and voxelwise lesion-deficit analyses. First, we used the geniculo-calcarine system as a validation testbed. Using logistic regressions we predicted right homonymous visual field deficits in 149 subjects with focal brain damage based on lesion location, with and without incorporating fiber tract information. A probabilistic fiber tract atlas [Wakana S, Jiang H, Nagae-Poetscher LM, Van Zijl PC, Mori S. Fiber tract-based atlas of human white matter anatomy. Radiology 2004;230:77-87] coregistered to our reference brain was used to estimate disconnection to the optic radiations and adjacent fiber tracts. When tract information was not incorporated, lesions in multiple sectors of the temporal lobe were associated with visual field defects. When the optic radiations were incorporated, this artifactual association was eliminated and the calcarine cortex was correctly isolated. Among the incorporated tracts, only the optic radiations significantly predicted visual field defects. Second, we applied the approach to impairments of higher visuoperceptual functions in 111 subjects who were administered the Hooper Visual Organization Test. We included all six association fiber tracts available in the atlas, plus the optic radiations. Tract inclusion narrowed the cortical sectors associated with impaired performance in a manner consistent with recent fMRI findings. The left cingulum and inferior longitudinal fasciculus, significantly predicted impairments. The results demonstrate the viability, validity and value of incorporating fiber tract information in lesion-deficit analyses. The enhanced analysis framework opens a new avenue for studying neural systems, with the potential to facilitate identification of both cortical sectors and fiber tracts critical for cognitive functioning.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
18625495
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"