Intracortical motor networks are affected in both the contralateral and ipsilateral hemisphere during single limb cold water immersion

Abstract

New Findings What is the central question of this study?How does single limb cold water immersion affect corticomotor function and intracortical circuitry in the motor cortex of each cerebral hemisphere? What is the main finding and its importance?Immersion of a single limb in very cold water caused an increase in corticomotor excitability and intracortical facilitation, and a decrease in intracortical inhibition, in the motor cortex of both hemispheres. These findings provide evidence that intense sensory stimuli induce widespread changes in motor circuitry in the contralateral, as well as the ipsilateral, hemisphere. Abstract Although responses to noxious stimuli have been extensively studied for the contralateral hemisphere, little is known about how the ipsilateral hemisphere may be affected. Therefore, this study examined how exposing a single limb to noxious cold stimuli affects motor output arising from both the contralateral and ipsilateral hemisphere. A total of 17 healthy adults participated in three experiments. Single‐ and paired‐pulse TMS protocols were used to identify how immersing a single upper limb in cold water (4.0 ± 0.5 °C) affects inhibitory and facilitatory circuits in the primary motor cortex (M1) of the contralateral (experiment 1) and ipsilateral (experiment 2) hemisphere. The third experiment used a reaction time task to assess the functional consequences of acute adaptations in the ipsilateral M1. The target muscle in all experiments was the extensor carpi radialis brevis (ECRB). Immersion of a single limb in cold water increased self‐perception of pain and temperature, and increased EMG amplitude of the immersed limb. During immersion, motor evoked potentials and intracortical facilitation increased, whereas short interval intracortical inhibition decreased, for both the ipsilateral M1 and contralateral M1. Activity in the ipsilateral hemisphere to the limb immersed in cold water also slowed reaction time for the non‐immersed limb. Our findings suggest that altered motor responses from single limb cold water immersion are not restricted to a single hemisphere. Instead, widespread activation of somatosensory systems influences inhibitory and facilitatory circuits in the primary motor cortex of each hemisphere.

The effect of experimental pain on the excitability of the corticospinal tract in humans: A systematic review and meta‐analysis

“…For forearm pain, no significant modulation of corticospinal excitability was observed “during pain” ( n = 5; SMD: −0.55 [95%CI −1.75, 0.65]; p =.37 | I 2 = 93.2%) (Cheong et al., 2003; Delahunty et al., 2019; Farina et al., 2001; Larsen et al., 2018; Le Pera et al., 2001) and “after pain” ( n = 4; SMD: −0.45 [95%CI −0.97, 0.06]; p =.08 | I 2 = 69.18%) (Cheong et al., 2003; Larsen et al., 2018; Le Pera et al., 2001; Schabrun et al., 2017). For arm pain, no significant change was observed “during pain” ( n = 2, SMD: −0.10 [95%CI −0.33, 0.53]; p =.65 | I 2 = 0%) (DelSanto et al., 2007; Martin et al., 2008) and “after pain” ( n = 2; SMD: −0.10 [95%CI −0.53, 0.33]; p =.64 | I 2 = 0%) (DelSanto et al., 2007; Martin et al., 2008).…”

“…For muscle pain at the forearm, no significant change in corticospinal excitability was observed at rest “during pain" ( n = 2; SMD: −0.13 [95%CI −1.36, 1.11], p =.84 | I 2 = 87.2%) (Larsen et al., 2018; Le Pera et al., 2001) and “after pain” ( n = 3; SMD: −0.47 [95%CI −1.24, 0.30], p =.23 | I 2 = 75.8%) (Larsen et al., 2018; Le Pera et al., 2001; Schabrun et al., 2017). There was also no significant effect of cutaneous pain at the forearm at rest “during pain” ( n = 2; SMD: −1.25 [95%CI −5.52, 3.03], p =.57 | I 2 = 92.7%) (Delahunty et al., 2019; Farina et al., 2001).…”

Common Motor Drive Triggers Response of Prime Movers When Two Fingers Simultaneously Respond to a Cue

“…The RT was defined as the time between the start cue and the EMG onset. In previous studies, the RT has been determined by visual inspection [31][32][33][34][35][36]. It has been shown that the automatic detection of the EMG onset is inaccurate and visual inspection is recommended [37].…”

The Effects of Cold Water Immersion on the Recovery of Drop Jump Performance and Mechanics: A Pilot Study in Under-20 Soccer Players

“…However, the movement plane of the sledge is strictly sagittal, and the lab set-up constrained the use of three-dimensional motion capture. Further, although asymmetrical motor responses have been reported after single limb CWI (Delahunty et al, 2019), it is unknown if this is long-lasting and a bilateral immersion likely negated these effects.…”