| | TMS protocol | Stimulation characteristics | Neural mechanisms | Studies utilizing |
| | Single-pulse TMS | | Active motor threshold (AMT) | % MSO to elicit a 100-200 μV MEP in ≥5/10 trials during a tonic contraction of the target muscle [37, 44, 114, 115]. | Corticospinal excitability; influenced by Glu [33, 98]. | [54, 70, 74] | | Cortical silent period (CSP) | Reduced background EMG following MEP when TMS is delivered during a tonic contraction of the target muscle contralateral to M1 [37, 44, 74, 116–119]. | Spinal and cortical inhibition; influenced by GABABRs [35, 44, 98, 108, 109]. | [42, 71, 74, 76, 78, 85, 87] | | Ipsilateral silent period (iSP) | Reduced background EMG when TMS is delivered during a tonic contraction of the target muscle ipsilateral to M1 [65, 74, 118, 120–123]. | Transcallosal inhibition; influenced by GABABRs [33, 123–125]. | [54, 65, 73, 74] | | Motor-evoked potential (MEP) | Deflection in the EMG trace of the target muscle following the delivery of a TMS pulse over the M1 [44, 126, 127]. | Amplitude reflects corticospinal excitability; latency reflects corticomotor latency; influenced by Glu, GABA, 5-HT, and NE [37, 44, 68, 107, 126–129]. | [8, 42, 43, 63, 66, 68–75, 78, 79, 81, 82, 85–88] | | Resting motor threshold (RMT) | % MSO to elicit a 50 μV MEP in ≥5/10 trials in a resting target muscle [44, 114]. | Corticospinal excitability; influenced by Glu [33, 98, 115, 127]. | [42, 43, 54, 64, 65, 70–75, 79–81, 87] |
| | Paired-pulse TMS | | Central motor conduction time (CMCT) | Difference between spinal cord-/brainstem-to-muscle MEP latency and M1-to-muscle MEP latency [35, 37, 44, 114, 130–133]. | Corticomotor latency [33, 35, 37, 93]. | [43, 54, 65, 68–70, 72, 73, 77–79, 82, 83, 86–88] | | Dorsal premotor-primary motor cortex interaction (PMd-M1) | Sub-/suprathreshold CS over PMd and suprathreshold TS over M1 [67, 134, 135]. | Cortical inhibition/facilitation [67, 134]. | [67] | | Interhemispheric inhibition (IHI) | Sub-/suprathreshold CS and suprathreshold TS over homologous M1 representations [35, 44, 77, 122, 135–137]. | Cortical inhibition/facilitation; influenced by GABABRs [122, 135–138]. | [77] | | Intracortical facilitation (ICF) | Subthreshold CS followed 10-15 ms later by a suprathreshold TS [33, 35, 44, 139]. | Cortical facilitation; influenced by Glu [35, 98, 107, 140]. | [42, 67, 70, 74, 81, 87] | | Long-interval intracortical inhibition (LICI) | Suprathreshold CS and TS separated by 50-200 ms [44, 141–143]. | Intracortical inhibition; influenced by GABABRs [98, 144, 145]. | [42, 67] | | Short-interval intracortical facilitation (SICF) | Sub-/suprathreshold CS and TS separated by 1.1-4.5 ms [44, 67, 121, 146–149]. | Cortical facilitation; influenced by GABAARs [35, 37, 44, 98, 107, 146, 147]. | [67, 72] | | Short-interval intracortical inhibition (SICI) | Subthreshold CS and suprathreshold TS separated by 1-5 ms [37, 114, 139, 143, 150]. | Intracortical inhibition; influenced by GABA, GABAARs [98, 107, 144, 151, 152]. | [42, 67, 70, 71, 74, 81, 87] | | Short-latency afferent inhibition (SAI) | Electrical CS over median nerve followed by a suprathreshold TMS TS over 20-25 ms later [44, 153–155]. | Sensorimotor integration; influenced by Ach and GABAARs [33, 98, 153, 155]. | [43] | | Triple stimulation technique (TST) | Suprathreshold TMS delivered over M1 and electrical stimulation over proximal and distal ends of the peripheral nerve supplying the target muscle [35, 156, 157]. | Corticospinal conduction [37, 88, 157, 158]. | [84, 88] |
|
|
