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

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.

Changes in the TMS-evoked potential N100 in the dorsolateral prefrontal cortex as a function of depression severity in adolescents

“…Neuronavigation, although helpful during TMS coil positioning, significantly increases measurement time (Julkunen et al 2009 ). Instead, coil positions were chosen based on the DLPFC localization method of Rusjan and colleagues ( 2010 ), which has been used previously in other studies (Cash et al 2017 ; Fitzgerald et al 2009 ; Noda et al 2021 ; Rogasch et al 2015 ; Sun et al 2016 ).…”

Clinical Neurophysiology, Neuroimaging, and Neuromodulation of Neuropsychiatric Disorders

“…Furthermore, in the elderly, P60 was delayed after M1-spTMS and N45-P60 was delayed in the right median after left DLPFC-spTMS, whereas in patients, N45-P60 was delayed in the right central area after DLPFC-spTMS. Our results suggest that the inhibitory and excitatory mechanisms, as indexed by TEP, may be altered in the elderly and in schizophrenia patients [7].…”

TMS-evoked potentials: neurophysiological biomarkers for diagnosis and response to ventriculoperitoneal shunt in normal pressure hydrocephalus

“…Opposite to that, in response to frontal network (DLPFC) stimulation, the P180 peak latency seems to be delayed. TMS-EEG literature established that TEP peak latencies are generally delayed with old age [47][48][49][50] . In our study NPH responders demonstrated an earlier M1 P60 and P180 latencies in comparison to age matched controls, showing a different effect than typical healthy ageing.…”