Transcranial Magnetic Stimulation Elicits Coupled Neural and Hemodynamic Consequences

Abstract

Transcranial magnetic stimulation (TMS) is an increasingly common technique used to selectively modify neural processing. However, application of TMS is limited by uncertainty concerning its physiological effects. We applied TMS to the cat visual cortex and evaluated the neural and hemodynamic consequences. Short TMS pulse trains elicited initial activation (approximately 1 minute) and prolonged suppression (5 to 10 minutes) of neural responses. Furthermore, TMS disrupted the temporal structure of activity by altering phase relationships between neural signals. Despite the complexity of this response, neural changes were faithfully reflected in hemodynamic signals; quantitative coupling was present over a range of stimulation parameters. These results demonstrate long-lasting neural responses to TMS and support the use of hemodynamic-based neuroimaging to effectively monitor these changes over time.

Continuous theta burst transcranial magnetic stimulation reduces resting state connectivity between visual areas

“…These results highlight the important possibility that different protocols of TMS are likely to affect neurons in a different fashion. While online TMS induces firing in a subset of the neurons in the stimulated area that interferes with signal processing (Allen et al 2007), offline cTBS is likely to lead to a lowered excitability of the stimulated area (Allen et al 2007;Huang et al 2005). Thus it is perhaps not surprising that online TMS and offline cTBS affect the perceptual system in a different fashion.…”

“…One recently developed variant of repetitive transcranial magnetic stimulation (TMS), continuous theta burst stimulation (cTBS;Huang et al 2005), has shown promise because of its rapid application (Ͻ1 min), its ability to produce behavioral effects for up to 1 h after stimulation, and its connection to known neuronal mechanisms, such as long-term potentiation and depression (LTD). Indeed, research has shown that cTBS reduces motor cortical excitability in a manner consistent with LTD effects (Allen et al 2007;Di Lazzaro et al 2005Gentner et al 2008;Huang et al 2005Huang et al , 2007.…”

“…One recently developed variant of repetitive transcranial magnetic stimulation (TMS), continuous theta burst stimulation (cTBS;Huang et al 2005), has shown promise because of its rapid application (Ͻ1 min), its ability to produce behavioral effects for up to 1 h after stimulation, and its connection to known neuronal mechanisms, such as long-term potentiation and depression (LTD). Indeed, research has shown that cTBS reduces motor cortical excitability in a manner consistent with LTD effects (Allen et al 2007;Di Lazzaro et al 2005Gentner et al 2008;Huang et al 2005Huang et al , 2007.When applied to the occipital cortex, cTBS has been found to increase phosphene thresholds (PTs), such that higher stimulation intensity is needed to produce conscious visual experience (Franca et al 2006). One possibility is that such an increase in PTs is, at least in part, due to decreased connectivity between areas in the early visual cortex, which would make the Here we tested for this possibility by investigating the resting state connectivity between retinotopically defined regions in the early visual cortex after occipital application of cTBS.…”

A novel concurrent TMS‐fMRI method to reveal propagation patterns of prefrontal magnetic brain stimulation

“…TMS is a means of using electromagnetic induction in order to stimulate a brain region. Repetitive delivery of TMS pulses (rTMS) to a brain region modulates the excitability of the stimulated area, inducing changes in neural plasticity (Allen, Pasley, Duong, & Freeman, 2007). These neuroplastic changes outlast the duration of stimulation and are believed to be induced through long‐term potentiation/depression mechanisms (Esser et al, 2006; Ishikawa et al, 2007).…”

Voltage-sensitive dye imaging of transcranial magnetic stimulation-induced intracortical dynamics

“…Additionally, TMS has proved a valuable tool in basic brain research as its perturbative effects allow area-selective manipulation of immediate cortical function (9)(10)(11), as well as its long-lasting alteration through plasticity and learning protocols (12,13). However, direct measurements of the TMS-induced cortical dynamics at highly resolved spatiotemporal scales are missing because "online approaches" (14), using modern neuroimaging techniques such as functional MRI (fMRI) (15)(16)(17)(18), magnetoencephalography (19), EEG (20), and near-infrared (21) or intrinsic optical imaging (22), are limited in either spatial or temporal resolutions or in both.…”