Advanced lesion symptom mapping analyses and implementation as BCBtoolkit.

Chris Foulon,Richard Levy,Michel Thiebaut De Schotten,Serge Kinkingnéhun,Charlotte Rosso,Emmanuelle Volle,Leonardo Cerliani,Marika Urbanski

doi:10.1093/gigascience/giy004

Abstract

BackgroundPatients with brain lesions provide a unique opportunity to understand the functioning of the human mind. However, even when focal, brain lesions have local and remote effects that impact functionally and structurally connected circuits. Similarly, function emerges from the interaction between brain areas rather than their sole activity. For instance, category fluency requires the associations between executive, semantic, and language production functions.FindingsHere, we provide, for the first time, a set of complementary solutions for measuring the impact of a given lesion on the neuronal circuits. Our methods, which were applied to 37 patients with a focal frontal brain lesions, revealed a large set of directly and indirectly disconnected brain regions that had significantly impacted category fluency performance. The directly disconnected regions corresponded to areas that are classically considered as functionally engaged in verbal fluency and categorization tasks. These regions were also organized into larger directly and indirectly disconnected functional networks, including the left ventral fronto-parietal network, whose cortical thickness correlated with performance on category fluency.ConclusionsThe combination of structural and functional connectivity together with cortical thickness estimates reveal the remote effects of brain lesions, provide for the identification of the affected networks, and strengthen our understanding of their relationship with cognitive and behavioral measures. The methods presented are available and freely accessible in the BCBtoolkit as supplementary software [1].

Highlights

Patients with brain lesions provide a unique opportunity to understand the functioning of the human mind
Post hoc comparisons revealed that disconnections of the left frontal aslant (U = 90.0; P = 0. 0389), frontal inferior longitudinal (U = 69.0; P = 0. 0216) and frontal superior longitudinal (U = 75.0; P = 0. 0352) tracts, and the anterior (U = 28.5; P = 0. 0116) and long segment (U = 31.5; P = 0.0059) of the arcuate fasciculus were associated with a poorer performance in category fluency (Fig. 1)
These post hoc comparisons did not survive Bonferroni-Holm correction for multiple comparisons. These results indicate that poor performance measured in patients with brain damage can be associated to some extent with white matter tract disconnections

Summary

Introduction

Patients with brain lesions provide a unique opportunity to understand the functioning of the human mind. Our methods, which were applied to 37 patients with a focal frontal brain lesions, revealed a large set of directly and indirectly disconnected brain regions that had significantly impacted category fluency performance. The directly disconnected regions corresponded to areas that are classically considered as functionally engaged in verbal fluency and categorization tasks. These regions were organized into larger directly and indirectly disconnected functional networks, including the left ventral fronto-parietal network, whose cortical thickness correlated with performance on category fluency. Conclusions: The combination of structural and functional connectivity together with cortical thickness estimates reveal the remote effects of brain lesions, provide for the identification of the affected networks, and strengthen our understanding of their relationship with cognitive and behavioral measures.

Methods

Results

Discussion

Conclusion