Combining Multiple Data Acquisition Systems to Study Corticospinal Output and Multi-segment Biomechanics

Summary

The use of transcranial magnetic stimulation (TMS) to study human motor control requires the integration of data acquisition systems to control TMS delivery and simultaneously record human behavior. The present manuscript provides a detailed methodology for integrating data acquisition systems for the purpose of investigating human movement via TMS.

Abstract

Transcranial magnetic stimulation techniques allow for an in-depth investigation into the neural mechanisms that underpin human behavior. To date, the use of TMS to study human movement, has been limited by the challenges related to precisely timing the delivery of TMS to features of the unfolding movement and, also, by accurately characterizing kinematics and kinetics. To overcome these technical challenges, TMS delivery and acquisition systems should be integrated with an online motion tracking system. The present manuscript details technical innovations that integrate multiple acquisition systems to facilitate and advance the use of TMS to study human movement. Using commercially available software and hardware systems, a step-by-step approach to both the hardware assembly and the software scripts necessary to perform TMS studies triggered by specific features of a movement is provided. The approach is focused on the study of upper limb, planar, multi-joint reaching movements. However, the same integrative system is amenable to a multitude of sophisticated studies of human motor control.

Introduction

Transcranial magnetic stimulation (TMS) is a non-invasive method to stimulate the human cortex.^3,5 There are several TMS protocols that are used to understand cortical function such as single and multiple pulses, dual-site stimulation to probe functional connectivity, and repetitive pulses to promote neural plasticity.^4,6-8 TMS protocols may also be combined to advance the present understanding of human cortical processes and guide neural rehabilitation strategies. In addition to stimulating the cortex, TMS can also be used to understand sub-cortical function by stimulation of the corticospinal tract or cerebellum.

One....

Protocol

NOTE: The following protocol can be applied to a variety of experiments. Below are details regarding an experiment that involves a visually guided arm reaching task to one of six spatial targets displayed on a computer monitor. TMS, to probe corticospinal excitability, is triggered by either analog signals emerging from the movement (i.e., EMG or electrogoniometer input) or digital signals generated from the sweep-based data acquisition software. This study was approved by the McMaster Research Ethics Board in accordance with the Declaration of Helsinki. A sample dataset is provided.

1. Hardware/software Requirements

Results

Figure 3 displays the results from a single trial. In this trial, Figure 3A shows the initial position of the participant and, after an auditory 'go' cue, the participant moved as quickly and accurately as possible to the target (i.e., the final position). The sweep-based data acquisition software triggered a TMS pulse based on EMG onset in the biceps brachii muscle. This permitted the measure of corticospinal output directed to upper arm muscles.......

Discussion

The present manuscript details an innovative method to integrate TMS and motion capture systems in the context of a visuo-motor task. To make rapid and meaningful advances in the study of human motor control, it is essential that methodologies allow for precise communication across multiple hardware and software systems. The paradigm presented could be used to study a variety of research interests including the cortical contribution to motor learning, the neurophysiology of motor control, and multi-joint movement contr.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Polhemus FASTRAK	Polhemus Inc.		6 degrees of freedom electromagnetic motion tracking device with 4 sensors
Presentation	Neurobehavioural Systems Inc.		A fully programmable software for experiments involving data acquisition and stimulus delivery
Cutom built Exoskeleton	80/20 Inc. - The industrial erector set	Varies	Various parts used to build the exoskeleton
Brainsight	Rogue Research Inc.		Neuronavigation software to track coil position throughout the experiment