The impact of modern jazz dance on the electrical brain activity

Dance as one of the earliest cultural assets of mankind is practised in different cultures, mostly for wellbeing or for treating psycho-physiological disorders like Parkinson, depression, autism. However, the underlying neurophysiological mechanisms are still unclear and only few studies address the effects of particular dance styles. For a first impression, we were interested in the effects of modern jazz dance (MJD) on the brain activation that would contribute to the understanding of these mechanisms. 11 female subjects rehearsed a MJD choreography for three weeks (1h per week) and passed electroencephalographic (EEG) measurements in a crossover-design thereafter. The objectives were to establish the differences between dancing physically and participating just mentally with or without music. Therefore, each subject realized the four following test conditions: dancing physically to and without music, dancing mentally to and without music. Each of the conditions were performed for 15 minutes. Before and after each condition, the EEG activities were recorded under resting conditions (2 min. eyes-open, 2 min. eyes-closed) followed by a subsequent wash-out phase of 10 minutes. The results of the study revealed no time effects for the mental dancing conditions, either to or without music. An increased electrical brain activation was followed by the physical dancing conditions with and without music for the theta, alpha-1, alpha-2, beta and gamma frequency band across the entire scalp. Especially the higher frequencies (alpha-2, beta, gamma) showed increased brain activation across all brain areas. Higher brain activities for the physical dancing conditions were identified in comparison to the mental dancing condition. No statistically significant differences could be found as to dancing to or without music. Our findings demonstrate evidence for the immediate influence of modern jazz dance and its sweeping effects on all brain areas for all measured frequency bands, when dancing physically. In comparison, dancing just mentally does not result in similar effects.

5 99 right-hemispheric alpha frequencies. Thus, there is evidence for coherence between the right-100 hemispheric alpha synchronization and creativity. 101 Indeed, these studies showed support for various effects of dance observations. The influence 102 of physically self-executed, during and immediately after, dance movements is a rarer 103 research objective. 104 Commonalities and differences between the mental and active learning of a dance was 105 investigated by Cross et al. [33]. They measured common active brain areas with fMRI just as 106 Cross, Hamilton and Grafton had done [28] during the process of learning a techno dance 107 sequence through observation only and also by physically learning it. After five days of 108 rehearsal, the premotor and parietal brain areas were more activated than before. A study by 109 Müller et al. [34] investigated two groups of elderly non-dancers (68-80 years) over a period 110 of six to 18 months. The first group realized dance training sessions and the second group a 111 fitness training. After six months, the MRI-test provided evidence for increased grey matter 112 volume at the gyrus praecentralis and an increase at the gyrus parahippocampalis, after 18 113 month for the dance training group only. 114 Similar to the study by Fink et al. [32], an increased alpha activity and beta frequency could 115 be observed for professional dancers in the study by Ermutlu et al. [35]. They compared 116 dancers' with fastball athletes' brain activity as well as that of a control group. The  In sum, the premotor cortex, parietal areas and the cerebellar revealed more activation while 131 observing dance movements in comparison to the baseline brain activity [26][27][28][29] non-inclusion could be found.

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The aim of the current study is to examine the different effects on the spontaneous electrical 147 brain activity caused by physical dance or the imagination of dance, with and without music.    Table 1).

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The ANOVA of the alpha-1 frequency band data showed an interaction effect for testing    Table 1).

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The ANOVA for the beta-frequency band led to significant differences between the pre-and x time x electrodes was found, however, post hoc comparisons showed significant differences. 12

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The analysis also revealed an increased brain activation after the pwm condition compared to  Table 1).

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The  Table 1). In the present study, we could assess an increased power across all frequency bands when the 288 subjects danced physically to or without music in comparison to the mental dance conditions.

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Especially, the condition "physical dance with music" (pwm) led to an increased power of the 290 alpha-2, beta and gamma frequencies at the frontal, temporal and occipital brain areas during 291 post-test. Compared to the theta, alpha-1, alpha-2 and beta frequency bands, the gamma 292 frequency showed increased power at the central and parietal brain areas. alterations in the brain. For this reason, we do not discuss the mental dancing condition in 338 more detail, but rather parse the physical dancing conditions.

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For the pwm and pnm conditions, the theta and the alpha-1 frequencies were activated at 340 fewer electrode positions, compared to the higher frequency bands. Theta activity is primarily 341 associated with a drowsy state and appears more often in childhood than adulthood [43]. frontal temporal and occipital brain areas after physically dancing to and without music (see 357 for details Table 1). The alpha state (7,5-12,5 Hz) is often related to psychic and physical where a gross motor movement technique was trained without repetition and without 384 augmented feedback [59]. Both studies go along with and extend the "transient hypofrontality the assumption that exactly these mechanisms are activated. not only in combination with motoric tasks, but also in working memory, long-term memory 453 and in conscious awareness [43,69]. It could be suggested that the working memory and the 454 conscious awareness are involved in the performance of a modern jazz dance, which can be 455 substantial because of the empowerment of the frontal lobe (see above for the characteristics).

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The gamma frequency is also supposed to be involved in memory processes, if they appear in 457 temporal brain areas [43]. This process is highly probable regarding the memorizing of the 458 complex choreography, which increases in complexity when dancing in accordance to music 459 is demanded.

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In conclusion, the findings of this study reveal distinct brain activation across the entire scalp 462 and for all frequency bands concerning the condition dancing physically to music and without 463 music. Especially the alpha-2, beta and gamma frequencies were significantly higher after