Neural signatures of Trail Making Test performance: Evidence from lesion-mapping and neuroimaging studies

Abstract

The Trail Making Test (TMT) is an extensively used neuropsychological instrument for the assessment of set-switching ability across a wide range of neurological conditions. However, the exact nature of the cognitive processes and associated brain regions contributing to the performance on the TMT remains unclear. In this review, we first introduce the TMT by discussing its administration and scoring approaches. We then examine converging evidence and divergent findings concerning the brain regions related to TMT performance, as identified by lesion-symptom mapping studies conducted in brain-injured patients and functional magnetic resonance imaging studies conducted in healthy participants. After addressing factors that may account for the heterogeneity in the brain regions reported by these studies, we identify future research endeavours that may permit disentangling the different processes contributing to TMT performance and relating them to specific brain circuits.

Keywords: Mental flexibility; Set-switching; TMT; VLSM; fMRI.

Fig. 1

Brain regions identified by VLSM and fMRI studies of the TMT. The brain structures reported in VLSM (a), task-related fMRI (b) and resting-state fMRI (c) were mapped over the Harvard-Oxford brain atlas. The consistency of the neural effects was expressed in percentage, and calculated as the ratio between the number of studies that reported a brain region and the total number of reviewed studies.