Sensorimotor Cortical Thickness Moderates Corticospinal Excitability

Transcranial magnetic stimulation (TMS) is commonly used to examine corticospinal excitability (CSE) and related behaviors. Individual differences in brain morphology may influence responses TMS, but clarification needed. PURPOSE: To explore the relationship between cortical thickness CSE when targeted lower extremity corticomotor representation. METHODS: Twenty women (20.4 ± 1.8 yr) completed 3 T T1-weighted MRI scans determine of regions interest including precentral gyrus (PrG), postcentral (PoG) paracentral lobule (PCL). Corticospinal was assessed during an isometric squat performed at 15% maximal force. Five single pulses were delivered 40-90% stimulator output (SO) randomized 10% increments using a figure-of-eight coil targeting primary motor cortex vastus lateralis (VL) measured VL as peak-to-peak amplitude electromyographic response from 15-65 ms post-TMS. The largest MEP each SO selected, averaged retained for analysis. Pearson correlations CSE, PCL, PrG PoG thickness. RESULTS: exhibited moderate inverse PCL (r = -0.43, p < 0.01), not correlated with 0.01, 0.95) or 0.03, 0.84) CONCLUSION: are sensitive sensorimotor morphology. In contrast PoG, associated which supports contention that contributions topographically specific. Cortical should be further explored moderating factor TMS. Knowledge inter-individual aid designing individualized therapies optimize diagnostic outcome measures.