A method to induce human cortical long-term potentiation by acoustic stimulation

Figures & data

Figure 1. The diagram of the paradigm. P and T stood for the probe and tetanus block, respectively. (a) The Tetanus condition and (b) the control condition.

Figure 2. The diagram of the T-block and P-block.

Figure 3. Butterfly plots and mean global field power (MGFP).

Table 1. The peak time and time window of N1 wave.

Stimuli type^a	Peak time (ms)	Time window^b (ms)
1 kHz PT	122	(102–153)
1 kHz NBN	126	(107–160)
6 kHz PT	129	(107–157)
6 kHz NBN	139	(110–169)
WN	124	(102–155)

^a PT: pure-tone; NBN: narrow-band noise; WN: white noise.

^b The time window of a N1 peak was the interval between the two time instances at which the amplitude of the AEP dropped to the 75% of the peak.

Figure 4. The 2D map of the scalp current density of N1.

Figure 5. Source localization of N1. Grand averaged data showed the N1 source distributions of pre- (a) and post-tetanus (b) conditions.

Figure 6. Auditory tetanic stimulation induced potentiation on the N1. In the Tetanus condition (left column), the post-tetanus amplitude of the N1 was higher than that of pre-tetanus, whereas there was no such increase in the Control condition (right column). (a) 1 kHz PT, (b) 1 kHz NBN, (c) 6 kHz PT, (d) 6 kHz NBN, and (e) WN. The black lines are pre-tetanus waves, and the red lines are post-tetanus waves.

Table 2. Bonferroni’s corrected p values for the ANOVA results.

Stimulus (I)	Stimulus (J)	I–J	p Value
1 kHz PT	1 kHz NBN	0.6213	<.01
	6 kHz PT	1.1111	<.01
	6 kHz NBN	1.3467	<.01
	WN	–4.6811	<.01
1 kHz NBN	1 kHz PT	–0.6213	<.01
	6 kHz PT	0.4897	<.01
	6 kHz NBN	0.7253	<.01
	WN	–5.3024	<.01
6 kHz PT	1 kHz PT	–1.1111	<.01
	1KHz NBN	–0.4897	<.01
	6 kHz NBN	0.2355	.463
	WN	–5.7922	<.01
6 kHz NBN	1 kHz PT	–1.3467	<.01
	1 kHz NBN	–0.7253	<.01
	6 kHz PT	–0.2355	.463
	WN	–6.0278	<.01
WN	1 kHz PT	4.6811	<.01
	1 kHz NBN	5.3024	<.01
	6 kHz PT	5.7922	<.01
	6 kHz NBN	6.0278	<.01

Table 3. Analysis of stimulus and condition.

Stimulation	Condition	Time	N1 (uV, x ± s)	t value	p Value
1 kHz PT	Tetanus	Pre	–4.3300 ± 0.3130	–10.384	.000
		Post	–5.2310 ± 0.4818
	Control	Pre	–5.4581 ± 0.6721	3.160	.012
		Post	–5.2691 ± 0.7048
1 kHz NBN	Tetanus	Pre	–3.4589 ± 0.4748	–21.262	.000
		Post	–4.8464 ± 0.3491
	Control	Pre	–4.3799 ± 0.5369	–5.031	.001
		Post	–4.5265 ± 0.5460
6 kHz PT	Tetanus	Pre	–2.8176 ± 0.3012	–12.953	.000
		Post	–3.3534 ± 0.3842
	Control	Pre	–5.0904 ± 0.3921	4.938	.001
		Post	–4.8049 ± 0.3046
6 kHz NBN	Tetanus	Pre	–3.5526 ± 0.4586	–12.084	.000
		Post	–4.5312 ± 0.4067
	Control	Pre	–4.3867 ± 0.4742	0.363	.725
		Post	–4.3634 ± 0.4038
WN	Tetanus	Pre	–8.1804 ± 0.5204	–25.568	.000
		Post	–9.6863 ± 0.6289
	Control	Pre	–10.3893 ± 1.5385	4.795	.001
		Post	–10.2201 ± 1.5184

Table 4. The percentage of the N1 amplitude of post-tetanus blocks over the baseline.

Stimulation	Condition	Baseline value (uV)	P5(%, x ± s)	P6(%, x ± s)	P7(%, x ± s)	P8(%, x ± s)
1 kHz PT	Tetanus	–4.330	25.06 ± 11.69	15.65 ± 12.07	15.61 ± 10.58	26.90 ± 12.60
	Control	–5.458	8.50 ± 15.71	–2.11 ± 13.01	–6.73 ± 13.97	–13.51 ± 9.73
1 kHz NBN	Tetanus	–3.459	34.78 ± 12.93	31.15 ± 8.02	58.57 ± 13.33	35.96 ± 10.52
	Control	–4.380	5.29 ± 13.49	4.81 ± 14.76	10.56 ± 14.52	–7.28 ± 11.70
6 kHz PT	Tetanus	–2.818	29.94 ± 13.75	11.34 ± 15.59	18.70 ± 20.53	16.09 ± 13.53
	Control	–5.090	6.57 ± 9.50	–8.51 ± 5.55	–12.61 ± 6.94	–7.90 ± 7.81
6 kHz NBN	Tetanus	–3.553	43.96 ± 14.79	35.22 ± 15.06	4.97 ± 13.78	26.04 ± 7.89
	Control	–4.387	–6.19 ± 8.59	4.15 ± 9.90	–4.72 ± 9.72	4.63 ± 12.64
WN	Tetanus	–8.180	15.27 ± 9.85	16.52 ± 7.93	19.86 ± 7.39	21.99 ± 6.40
	Control	–10.389	0.89 ± 13.83	1.66 ± 15.64	–6.71 ± 14.65	–2.35 ± 14.70

Figure 7. The standard deviation of the percentage of the post-tetanus N1 amplitude over baseline was illustrated for the five stimuli in the Tetanus condition and the Control condition, with the Tetanus condition plotted as a dark bar and the Control condition as a light bar.

Figure 8. (a) The percentage of the post-tetanus N1 amplitude over time and bandwidth for a center frequency of 1 kHz and (b) the percentage of the post-tetanus N1 amplitude over time and bandwidth for a center frequency of 6 kHz, where x-axis was the post-tetanus time in minutes, y-axis was the bandwidth of the stimulus ranging from 0 octave, 1/8 octave to full band, and z-axis was the percentage of the post-tetanus N1 amplitude over the baseline.