Author(s): MASHIKI, Y., KANEKO, N., KATO, T., YAMASAKI, D., TAKAHASHI, R., NAKAZAWA, K., Institution: THE UNIVERSITY OF TOKYO, Country: JAPAN, Abstract-ID: 1613

INTRODUCTION:
Emotions significantly influence sports performance via modulation of motor control. A previous study indicated that negative autobiographical memories increase corticospinal excitability (CSE), which plays a crucial role in motor control [1]. However, we need to deal with various emotions, such as happiness, sadness, fear, and anger. Therefore, it is essential to explore the effect of discrete emotions for a better understanding of the relationship between emotions and motor control. Furthermore, it may provide valuable insight into improving responsiveness to various situations during sports performance by identifying the muscles in which CSE is likely to be modulated by emotions. Thus, this study aimed to investigate: (1) the modulation of CSE by discrete autobiographical emotional memories and (2) the muscle-specificity of CSE modulation in response to emotions.
METHODS:
Sixteen healthy individuals (22–30 years old) participated in this study. Participants were seated on a chair. Electromyographic activity was recorded from the flexor carpi radialis (FCR), extensor carpi radialis (ECR), first dorsal interosseous (FDI), and abductor pollicis brevis (APB) muscles. CSE was evaluated by motor-evoked potential (MEP) amplitudes which were elicited by transcranial magnetic stimulation (TMS) to the primary motor cortex. Initially, participants were asked to write down situations in which they had experienced happiness, sadness, fear, and anger. For the neutral condition, participants were asked to describe their typical morning routine. We recorded 12 MEPs as they recalled the written situations for each emotion. MEP amplitudes during the recall of happiness, sadness, fear, and anger were normalized to the MEP amplitudes in the neutral condition. A statistical analysis was conducted using a two-way analysis of variance (ANOVA) with aligned rank transform. The ANOVA included two factors: 4 muscles and 5 emotions. Contrast tests were used as subsequent post-hoc tests. The level of significance was set to p < 0.05.
RESULTS:
The two-way ANOVA showed a significant main effect for emotions (p = 0.004), but not for muscles (p = 0.183) and the interaction between muscles and emotions (p = 0.502). Subsequent post-hoc tests on emotions showed that the fear emotion significantly increased MEP amplitudes more than the neutral condition (p = 0.001, + 39.3%). On the other hand, there were no significant differences between any of the other emotions (p > 0.05).
CONCLUSION:
Our results indicated that although no significant difference in MEP amplitudes was found between upper-limb muscles, the recall of autobiographical fear memories significantly increased MEP amplitudes. These suggest that the fear memories facilitate CSE and that this facilitation is non-specific to upper-limb muscles. Our finding enhances our comprehension of the interplay between emotions and motor control.
REFERENCE:
1. Mineo et al., Neuropsychologia, 2018.