Modulation of preparatory volitional motor cortical activity by paired associative transcranial magnetic stimulation

Abstract

Paired associative transcranial magnetic stimulation (PAS) has been shown to induce long-term potentiation (LTP)-like or long-term depression (LTD)-like change in excitability of human primary motor cortex (M1), as probed by motor evoked potential (MEP) amplitude. In contrast, little is known about PAS effects on volitional motor cortical activity. In 10 healthy subjects, movement related cortical potentials (MRCP) were recorded to index volitional motor cortical activity during preparation of simple thumb abduction (prime mover: abductor pollicis brevis, APB) or wrist extension movements (prime mover: extensor carpi radialis, ECR). PAS(LTP) increased, PAS(LTD) decreased, and PAS(control) did not change MEP(APB), while MEP(ECR), not targeted by PAS, remained unchanged in all PAS conditions. PAS(LTP) decreased MRCP negativity during the late Bereitschaftspotential (-500 to 0 ms before movement onset), only in the APB task, and predominantly over central scalp electrodes contralateral to the thumb movements. This effect correlated negatively with the PAS(LTP) induced increase in MEP(APB). PAS(LTD) and PAS(control) did not affect MRCP amplitude. Findings indicate a specific interference of PAS with preparatory volitional motor cortical activity, suggestive of a net result caused by increased M1 excitability and disrupted effective connectivity between premotor areas and M1.

Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research

“…A few studies explored EEG aftereffects after TBS (Katayama and Rothwell, 2007, Ishikawa et al, 2007), or PAS (Tsuji and Rothwell, 2002; Wolters et al, 2005). Aftereffects have been observed on a variety of EEG/EP-measures including oscillatory activity over motor and prefrontal areas (e.g., Strens et al, 2002 and Schutter et al, 2003) as well as somatosensory (e.g., Katayama and Rothwell, 2007; Ishikawa et al, 2007; Restuccia et al, 2007), visual (Schutter et al, 2003), cognitive (Evers et al, 2001a, b; Hansenne et al, 2004; Jing et al, 2001) and movement-related cortical potentials (Rossi et al, 2000; Lu et al, 2009), in accordance with the site of TMS. With three exceptions (Evers et al, 2001a, 2001b; Satow et al, 2003; Hansenne et al, 2004), all published studies reported significant aftereffects.…”

Cerebellum to motor cortex paired associative stimulation induces bidirectional STDP-like plasticity in human motor cortex

“…The randomly alternating protocol was developed in our group originally for the conventional PAS protocol (i.e., pairing of electrical peripheral nerve stimulation with TMS of the contralateral M1 HAND ) where it did not induce any significant change of MEP amplitude (Müller et al, 2007; Lu et al, 2009). The intensity of CS was kept at 95% AMT determined over the inion.…”

The effect of paired associative stimulation on fatigue resistance

“…However, there are studies showing no change in MEPs during slight contractions (Kumpulainen et al, 2012;Stefan et al, 2000Stefan et al, , 2004. The interpretation of the effect of PAS on active muscles is more complicated as can be seen in the study of Lu et al (2009) where a decrease of the movement-related cortical potentials (MRCP) in electroencephalography recordings was reported after an LTPlike PAS-protocol. Accordingly, performing the same movement pattern, simple thumb abduction, generated a decreased MRCP negativity after the PAS intervention.…”