Plasticity of the Primary Motor Cortex in Patients with Primary Brain Tumors.

Nathan W Kong,Suvarna Badhe,William R Gibb,Benjamin P Liu,Matthew C Tate

doi:10.1155/2020/3648517

Abstract

There are two neuron-level mechanisms proposed to underlie neural plasticity: recruiting neurons nearby to support the lost function (ipsilesional plasticity) and uncovering latent pathways that can assume the function that was lost (contralesional plasticity). While both patterns have been demonstrated in patient groups following injury, the specific mechanisms underlying each mode of plasticity are poorly understood. In a retrospective case series of 13 patients, we utilize a novel paradigm that analyzes serial fMRI scans in patients harboring intrinsic brain tumors that vary in location and growth kinetics to better understand the mechanisms underlying these two modes of plasticity in the human primary motor cortex. Twelve patients in our series had some degree of primary motor cortex plasticity, an area previously thought to have limited plasticity. Patients harboring smaller lesions with slower growth kinetics and increasing distance from the primary motor region demonstrated recruitment of ipsilateral motor regions. Conversely, larger, faster-growing lesions in close proximity to the primary motor region were associated with activation of the contralesional primary motor cortex, along with increased activation of the supplementary motor area. These data increase our understanding of the adaptive abilities of the brain and may lead to improved treatment strategies for those suffering from motor loss secondary to brain injuries.

Highlights

Plasticity refers to the ability of the brain to reorganize its functional networks during normal development as well as to preserve function during times of stress or pathology
All adult patients with primary intrinsic brain tumors from January 1, 2007, through December 31, 2016, who had two functional magnetic resonance imaging (fMRI) scans with finger-tapping motor tasks performed at Northwestern Memorial Hospital and had a surgical resection of the glioma between the two scans were eligible for inclusion (Figure 1)
Little is known regarding the mechanisms of plasticity resulting from damage to the human primary motor cortex

Summary

Introduction

Plasticity refers to the ability of the brain to reorganize its functional networks during normal development as well as to preserve function during times of stress or pathology. A variety of experimental tools have been used to measure plasticity in humans, including direct electrical cortical stimulation, transcranial magnetic stimulation, and functional magnetic resonance imaging (fMRI) Of these techniques, fMRI has been most extensively utilized given its ability to simultaneously interrogate multiple functional brain regions in a noninvasive manner. FMRI has been most extensively utilized given its ability to simultaneously interrogate multiple functional brain regions in a noninvasive manner Both language plasticity and motor plasticity have been demonstrated using fMRI in patients with brain lesions [1, 5,6,7,8,9,10,11]. A second mechanism relies on redundant connections that are typically silenced in the healthy brain Upon injury, these redundant synapses can be called upon to restore function. This recruitment of dormant connections has been reported in patients with strokes, gliomas, and arte-

Methods

Results

Conclusion