Prefrontal and posterior parietal contributions to the perceptual awareness of touch

M Rullmann,S Preusser,B Pleger

doi:10.1038/s41598-019-53637-w

Abstract

Which brain regions contribute to the perceptual awareness of touch remains largely unclear. We collected structural magnetic resonance imaging scans and neurological examination reports of 70 patients with brain injuries or stroke in S1 extending into adjacent parietal, temporal or pre-/frontal regions. We applied voxel-based lesion-symptom mapping to identify brain areas that overlap with an impaired touch perception (i.e., hypoesthesia). As expected, patients with hypoesthesia (n = 43) presented lesions in all Brodmann areas in S1 on postcentral gyrus (BA 1, 2, 3a, 3b). At the anterior border to BA 3b, we additionally identified motor area BA 4p in association with hypoesthesia, as well as further ventrally the ventral premotor cortex (BA 6, BA 44), assumed to be involved in whole-body perception. At the posterior border to S1, we found hypoesthesia associated effects in attention-related areas such as the inferior parietal lobe and intraparietal sulcus. Downstream to S1, we replicated previously reported lesion-hypoesthesia associations in the parietal operculum and insular cortex (i.e., ventral pathway of somatosensory processing). The present findings extend this pathway from S1 to the insular cortex by prefrontal and posterior parietal areas involved in multisensory integration and attention processes.

Highlights

Which brain regions contribute to the perceptual awareness of touch remains largely unclear
MRI scans and examination reports were collected by the Clinic of Cognitive Neurology, University Clinic Leipzig, and Max Planck Institute (MPI) for Human Cognitive and Brain Sciences in Leipzig, Germany
The chi-square test did not reveal significant differences between patients with and without hypoesthesia with respect to the presence of paresis (p = 0.12), we accounted for potentially confounding influences by a covariate added to both virtual lesion-symptom mapping (VLSM) models

Summary

Introduction

Which brain regions contribute to the perceptual awareness of touch remains largely unclear. We applied voxel-based lesion-symptom mapping to identify brain areas that overlap with an impaired touch perception (i.e., hypoesthesia). Downstream to S1, we replicated previously reported lesion-hypoesthesia associations in the parietal operculum and insular cortex (i.e., ventral pathway of somatosensory processing). Attenuated perception of touch was associated with lesions comprising the contralateral parietal operculum (OP), predominantly the more frontally located subdivisions OP 4 and 3, together with the insula, the putamen, and white matter projections to the prefrontal cortex. These findings were subsequently replicated in stroke patients with the same MRI-based VLSM methods[15]. Downstream to S1, we assumed to replicate previous VLSM findings including the parietal operculum, OP 1–4, together with the insular cortex[3,14,15]

Methods

Results

Discussion

Conclusion