Single-Pulse Transcranial Magnetic Stimulation-Evoked Potential Amplitudes and Latencies in the Motor and Dorsolateral Prefrontal Cortex among Young, Older Healthy Participants, and Schizophrenia Patients.

Yoshihiro Noda,Reza Zomorrodi,Robin F H Cash,Robert Chen,Mera S Barr,Pantelis Lioumis,Daniel M Blumberger,Zafiris J Daskalakis

doi:10.3390/jpm11010054

Abstract

Background: The combination of transcranial magnetic stimulation (TMS) with electroencephalography (EEG) allows for non-invasive investigation of cortical response and connectivity in human cortex. This study aimed to examine the amplitudes and latencies of each TMS-evoked potential (TEP) component induced by single-pulse TMS (spTMS) to the left motor (M1) and dorsolateral prefrontal cortex (DLPFC) among healthy young participants (YNG), older participants (OLD), and patients with schizophrenia (SCZ). Methods: We compared the spatiotemporal characteristics of TEPs induced by spTMS among the groups. Results: Compared to YNG, M1-spTMS induced lower amplitudes of N45 and P180 in OLD and a lower amplitude of P180 in SCZ, whereas the DLPFC-spTMS induced a lower N45 in OLD. Further, OLD demonstrated latency delays in P60 after M1-spTMS and in N45-P60 over the right central region after left DLPFC-spTMS, whereas SCZ demonstrated latency delays in N45-P60 over the midline and right central regions after DLPFC-spTMS. Conclusions: These findings suggest that inhibitory and excitatory mechanisms mediating TEPs may be altered in OLD and SCZ. The amplitude and latency changes of TEPs with spTMS may reflect underlying neurophysiological changes in OLD and SCZ, respectively. The spTMS administered to M1 and the DLPFC can probe cortical functions by examining TEPs. Thus, TMS-EEG can be used to study changes in cortical connectivity and signal propagation from healthy to pathological brains.

Highlights

Electroencephalography (EEG) studies probed by transcranial magnetic stimulation (TMS) have become feasible since Ilmoniemi et al initially developed the technology of the TMS-compatible EEG system [1]
Single-pulse TMS to the primary motor cortex (M1) as well as the dorsolateral prefrontal cortex (DLPFC) induces a wellcharacterized series of TMS-evoked potential (TEP) components of P30, N45, P60, N100, and P180 [9,10,13], that are highly reproducible [10] and the amplitudes of these TEP components vary depending on the intensity of TMS [14,15]
It has been reported that amplitudes of TEPs elicited by single-pulse TMS (spTMS) vary depending on the stimulated area [16], notable being reduced at the DLPFC compared to M1-spTMS [17,18]

Summary

Introduction

Electroencephalography (EEG) studies probed by transcranial magnetic stimulation (TMS) have become feasible since Ilmoniemi et al initially developed the technology of the TMS-compatible EEG system [1]. Single-pulse TMS (spTMS) to the primary motor cortex (M1) as well as the dorsolateral prefrontal cortex (DLPFC) induces a wellcharacterized series of TEP components of P30, N45, P60, N100, and P180 [9,10,13], that are highly reproducible [10] and the amplitudes of these TEP components vary depending on the intensity of TMS [14,15]. This study aimed to examine the amplitudes and latencies of each TMS-evoked potential (TEP) component induced by single-pulse TMS (spTMS) to the left motor (M1) and dorsolateral prefrontal cortex (DLPFC) among healthy young participants (YNG), older participants (OLD), and patients with schizophrenia (SCZ). The spTMS administered to M1 and the DLPFC can probe cortical functions by examining TEPs. TMS-EEG can be used to study changes in cortical connectivity and signal propagation from healthy to pathological brains

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Discussion

Conclusion