F Proessl1, M C Canino1, M E Beckner1, A M Sinnott1, S R Eagle1, A D LaGoy1,2, W R Conkright1, A J Sterczala1, C Connaboy1, F Ferrarelli2, A Germain2, B C Nindl1, S D Flanagan3. 1. Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, 3860 South Water St, Pittsburgh, PA, 15203, USA. 2. Department of Psychiatry, University of Pittsburgh Medical School, 3811 O'Hara Street, Pittsburgh, PA, 15213, USA. 3. Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, 3860 South Water St, Pittsburgh, PA, 15203, USA. Sdf29@pitt.edu.
Abstract
INTRODUCTION: The double-cone coil (D-CONE) is frequently used in transcranial magnetic stimulation (TMS) experiments that target the motor cortex (M1) lower-limb representation. Anecdotal evidence and modeling studies have shed light on the off-target effects of D-CONE TMS but the physiological extent remains undetermined. PURPOSE: To characterize the off-target effects of D-CONE TMS based on bilateral corticospinal responses in the legs and hands. METHODS: Thirty (N = 30) participants (9 women, age: 26 ± 5yrs) completed a stimulus-response curve procedure with D-CONE TMS applied to the dominant vastus lateralis (cVL) and motor-evoked potentials (MEPs) recorded in each active VL and resting first dorsal interosseous (FDI). As a positive control (CON), the dominant FDI was directly targeted with a figure-of-eight coil and MEPs were similarly recorded in each active FDI and resting VL. MEPMAX, V50 and MEP latencies were compared with repeated-measures ANOVAs or mixed-effects analysis and Bonferroni-corrected pairwise comparisons. RESULTS: Off-target responses were evident in all muscles, with similar MEPMAX in the target (cVL) and off-target (iVL) leg (p = 0.99) and cFDI compared with CON (p = 0.99). cFDI and CON MEPMAX were greater than iFDI (p < 0.01). A main effect of target (p < 0.001) indicated that latencies were shorter with CON but similar in all muscles with D-CONE. DISCUSSION: Concurrent MEP recordings in bilateral upper- and lower-extremity muscles confirm that lower-limb D-CONE TMS produces substantial distance-dependent off-target effects. In addition to monitoring corticospinal responses in off-target muscles to improve targeting accuracy in real-time, future studies may incorporate off-target information into statistical models post-hoc.
INTRODUCTION: The double-cone coil (D-CONE) is frequently used in transcranial magnetic stimulation (TMS) experiments that target the motor cortex (M1) lower-limb representation. Anecdotal evidence and modeling studies have shed light on the off-target effects of D-CONE TMS but the physiological extent remains undetermined. PURPOSE: To characterize the off-target effects of D-CONE TMS based on bilateral corticospinal responses in the legs and hands. METHODS: Thirty (N = 30) participants (9 women, age: 26 ± 5yrs) completed a stimulus-response curve procedure with D-CONE TMS applied to the dominant vastus lateralis (cVL) and motor-evoked potentials (MEPs) recorded in each active VL and resting first dorsal interosseous (FDI). As a positive control (CON), the dominant FDI was directly targeted with a figure-of-eight coil and MEPs were similarly recorded in each active FDI and resting VL. MEPMAX, V50 and MEP latencies were compared with repeated-measures ANOVAs or mixed-effects analysis and Bonferroni-corrected pairwise comparisons. RESULTS: Off-target responses were evident in all muscles, with similar MEPMAX in the target (cVL) and off-target (iVL) leg (p = 0.99) and cFDI compared with CON (p = 0.99). cFDI and CON MEPMAX were greater than iFDI (p < 0.01). A main effect of target (p < 0.001) indicated that latencies were shorter with CON but similar in all muscles with D-CONE. DISCUSSION: Concurrent MEP recordings in bilateral upper- and lower-extremity muscles confirm that lower-limb D-CONE TMS produces substantial distance-dependent off-target effects. In addition to monitoring corticospinal responses in off-target muscles to improve targeting accuracy in real-time, future studies may incorporate off-target information into statistical models post-hoc.
Entities:
Keywords:
Corticospinal excitability; Lower limbs; Motor cortex; Motor-evoked potentials; Transcranial magnetic stimulation
Authors: Nils Danner; Petro Julkunen; Mervi Könönen; Laura Säisänen; Jouko Nurkkala; Jari Karhu Journal: J Neurosci Methods Date: 2008-07-11 Impact factor: 2.390
Authors: Callum G Brownstein; Paul Ansdell; Jakob Škarabot; Ash Frazer; Dawson Kidgell; Glyn Howatson; Stuart Goodall; Kevin Thomas Journal: Exp Physiol Date: 2018-08-05 Impact factor: 2.969
Authors: Callum G Brownstein; Paul Ansdell; Jakob Škarabot; Glyn Howatson; Stuart Goodall; Kevin Thomas Journal: J Neurol Sci Date: 2018-09-05 Impact factor: 3.181
Authors: D Ciampi de Andrade; R Galhardoni; L F Pinto; R Lancelotti; J Rosi; M A Marcolin; M J Teixeira Journal: Neurophysiol Clin Date: 2012-09-03 Impact factor: 3.734
Authors: F Proessl; M C Canino; M E Beckner; W R Conkright; A D LaGoy; A M Sinnott; S R Eagle; B J Martin; A J Sterczala; P G Roma; M N Dretsch; Qi Mi; F Ferrarelli; A Germain; C Connaboy; B C Nindl; S D Flanagan Journal: J Appl Physiol (1985) Date: 2021-12-02