Anodal tDCS over the left DLPFC but not M1 increases muscle activity and improves psychophysiological responses, cognitive function, and endurance performance in normobaric hypoxia: a randomized controlled trial

Table 2 Mean value of the study variables under the three different stimulation conditions in hypoxia (n₌ 14)

Variables	Experimental conditions			Anova			Cohen’s d
Variables	Sham	M1	DLPFC	F	ɳ²_p	p	M1 vs. sham	DLPFC vs. Sham
Time to Exhaustion _(Min)	6.20 ± 1.8	7.54 ± 2.1	8.12 ± 2.7^a	F_(2,26)= 5.27	0.29	0.012	d = 0.67	d = 0.84
CWST _{(IG score)}	11.23 ± 5.2	11.27 ± 6.5	14.08 ± 6.7	F_(2,26)= 1.38	0.09	0.26	d < 0.01	d = 0.47
CRT _{(Milliseconds)}	499.64 ± 78.3	456.85 ± 97.4	412 ± 52.1^a	F_(2,26)= 4.36	0.25	0.023	d = 0.48	d = 1.3
Heart Rate _{(Beats Per Min)}	142.2 ± 13.9	138.8 ± 13.1	144.9 ± 13.5	F_(2,26)=1.01	0.07	0.37	d = 0.25	d = 0.19
O₂ saturation _(%)	80.14 ± 3.1	80.50 ± 4.2	82.57 ± 2.9	F_(2,26)= 2.44	0.16	0.10	d = 0.11	d = 0.82
EMG of VL _{(% of MVC)}	22.36 ± 9.1	25.54 ± 9.1	28.08 ± 8.4	F_(1.3,17.2)= 1.95	0.13	0.18	d = 0.35	d = 0.65
EMG of VM _{(% of MVC)}	28.92 ± 10.7	34.24 ± 11.9	39.69 ± 10.1^a	F_(1.3,18.1)=4.71	0.27	0.03	d = 0.46	d = 1.03
EMG of RF _{(% of MVC)}	13.83 ± 2.3	14.36 ± 2.1	15.24 ± 2.1	F_(2,26)= 1.28	0.09	0.29	d = 0.21	d = 0.64
Perceived exertion _(0–100)	99.07 ± 5.9	90.17 ± 17.1	88.94 ± 12.9^a	F_(2,26)=3.68	0.22	0.04	d = 0.77	d = 1.07
Affective responses _(-5/+5)	− 0.55 ± 1.5	0.54 ± 1.5	0.89 ± 1.5^*	F_(1.3,17.4)= 6.44	0.33	0.02	d = 0.68	d = 0.9
Felt arousal _(1–6)	2.21 ± 0.67	2.66 ± 0.5	2.85 ± 0.6^*	F_(2,26)= 3.7	0.22	0.04	d = 0.71	d = 0.96

Data are presented as mean ± standard deviation
tDCS transcranial direct current stimulation; M1 primary motor cortex; DLPFC dorsolateral prefrontal cortex; EMG electromyography; VL vastus lateralis; VM vastus medialis; RF rectus femoris; MVC maximum voluntary contraction; CWST color-word Stroop test; CRT choice reaction time
^a = significant different from sham (all ps < 0.05)

ISSN: 1471-2202