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Improved Anatomical Specificity of Non-invasive Neuro-stimulation by High Frequency (5 MHz) Ultrasound.

Li GF, Zhao HX, Zhou H, Yan F, Wang JY, Xu CX, Wang CZ, Niu LL, Meng L, Wu S, Zhang HL, Qiu WB, Zheng HR - Sci Rep (2016)

Bottom Line: Electromyography (EMG) collected from tail muscles together with the motion response videos were analyzed for evaluating the stimulation effects.Our results indicate that 5 MHz ultrasound can successfully achieve neuro-stimulation.It provides a smaller stimulation region, which offers improved anatomical specificity for neuro-stimulation in a non-invasive manner.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.

ABSTRACT
Low frequency ultrasound (<1 MHz) has been demonstrated to be a promising approach for non-invasive neuro-stimulation. However, the focal width is limited to be half centimeter scale. Minimizing the stimulation region with higher frequency ultrasound will provide a great opportunity to expand its application. This study first time examines the feasibility of using high frequency (5 MHz) ultrasound to achieve neuro-stimulation in brain, and verifies the anatomical specificity of neuro-stimulation in vivo. 1 MHz and 5 MHz ultrasound stimulation were evaluated in the same group of mice. Electromyography (EMG) collected from tail muscles together with the motion response videos were analyzed for evaluating the stimulation effects. Our results indicate that 5 MHz ultrasound can successfully achieve neuro-stimulation. The equivalent diameter (ED) of the stimulation region with 5 MHz ultrasound (0.29 ± 0.08 mm) is significantly smaller than that with 1 MHz (0.83 ± 0.11 mm). The response latency of 5 MHz ultrasound (45 ± 31 ms) is also shorter than that of 1 MHz ultrasound (208 ± 111 ms). Consequently, high frequency (5 MHz) ultrasound can successfully activate the brain circuits in mice. It provides a smaller stimulation region, which offers improved anatomical specificity for neuro-stimulation in a non-invasive manner.

No MeSH data available.


Related in: MedlinePlus

Acoustic intensity measurement and results.(a) Experimental setup for acoustic intensity measurement. (b,c) Are acoustic intensity distribution maps scanned without mouse skull by 1 MHz and 5 MHz ultrasound, respectively. (d,e) Were similar maps with mouse skull blocking. The intensities had been normalized to the peak value for each map. (f) Normalized intensity curves of 1 MHz from section planes of (b,d) at Y = 0 mm. (g) Normalized intensity curves of 5 MHz from section planes of (c,e). The dash line with asterisks marked shows the compensation result.
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f2: Acoustic intensity measurement and results.(a) Experimental setup for acoustic intensity measurement. (b,c) Are acoustic intensity distribution maps scanned without mouse skull by 1 MHz and 5 MHz ultrasound, respectively. (d,e) Were similar maps with mouse skull blocking. The intensities had been normalized to the peak value for each map. (f) Normalized intensity curves of 1 MHz from section planes of (b,d) at Y = 0 mm. (g) Normalized intensity curves of 5 MHz from section planes of (c,e). The dash line with asterisks marked shows the compensation result.

Mentions: The acoustic intensity maps were measured by the 3D ultrasound intensity measurement system (Fig. 2a). By comparing the normalized distribution maps of 1 MHz and 5 MHz ultrasound without the influence of skull (Fig. 2b,c), and the similar maps with skull (Fig. 2d,e), it can be seen that there are no obvious changes in terms of the size and location of focal regions when using different ultrasound frequencies. For more precise comparisons, the measured data were plotted on curves. Figure 2f shows normalized intensity curves of 1 MHz by sectioning Fig. 2b,d at Y = 0 mm. The solid line and the dotted line describe the intensity distribution along X axis without and with skull, respectively. The dotted line has lower peak value (89%, −0.5 dB) compared with the solid line (100%, 0 dB). Figure 2g shows the normalized intensity curves of 5 MHz. The dotted line has a much lower peak value (38%, −4.2 dB) compared with the solid line (100%, 0 dB). Acoustic compensation was added by increasing the amplitude of the ultrasound waveform in the driving part. The dash line with asterisks in Fig. 2g shows the acoustic intensities after acoustic compensation, which has peak value similar with the solid line. The difference of acoustic intensity after passing the skull is very small (<5%) for 1 MHz and 5 MHz ultrasound after acoustic compensation, which enable a fair comparison between different methods.


Improved Anatomical Specificity of Non-invasive Neuro-stimulation by High Frequency (5 MHz) Ultrasound.

Li GF, Zhao HX, Zhou H, Yan F, Wang JY, Xu CX, Wang CZ, Niu LL, Meng L, Wu S, Zhang HL, Qiu WB, Zheng HR - Sci Rep (2016)

Acoustic intensity measurement and results.(a) Experimental setup for acoustic intensity measurement. (b,c) Are acoustic intensity distribution maps scanned without mouse skull by 1 MHz and 5 MHz ultrasound, respectively. (d,e) Were similar maps with mouse skull blocking. The intensities had been normalized to the peak value for each map. (f) Normalized intensity curves of 1 MHz from section planes of (b,d) at Y = 0 mm. (g) Normalized intensity curves of 5 MHz from section planes of (c,e). The dash line with asterisks marked shows the compensation result.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837374&req=5

f2: Acoustic intensity measurement and results.(a) Experimental setup for acoustic intensity measurement. (b,c) Are acoustic intensity distribution maps scanned without mouse skull by 1 MHz and 5 MHz ultrasound, respectively. (d,e) Were similar maps with mouse skull blocking. The intensities had been normalized to the peak value for each map. (f) Normalized intensity curves of 1 MHz from section planes of (b,d) at Y = 0 mm. (g) Normalized intensity curves of 5 MHz from section planes of (c,e). The dash line with asterisks marked shows the compensation result.
Mentions: The acoustic intensity maps were measured by the 3D ultrasound intensity measurement system (Fig. 2a). By comparing the normalized distribution maps of 1 MHz and 5 MHz ultrasound without the influence of skull (Fig. 2b,c), and the similar maps with skull (Fig. 2d,e), it can be seen that there are no obvious changes in terms of the size and location of focal regions when using different ultrasound frequencies. For more precise comparisons, the measured data were plotted on curves. Figure 2f shows normalized intensity curves of 1 MHz by sectioning Fig. 2b,d at Y = 0 mm. The solid line and the dotted line describe the intensity distribution along X axis without and with skull, respectively. The dotted line has lower peak value (89%, −0.5 dB) compared with the solid line (100%, 0 dB). Figure 2g shows the normalized intensity curves of 5 MHz. The dotted line has a much lower peak value (38%, −4.2 dB) compared with the solid line (100%, 0 dB). Acoustic compensation was added by increasing the amplitude of the ultrasound waveform in the driving part. The dash line with asterisks in Fig. 2g shows the acoustic intensities after acoustic compensation, which has peak value similar with the solid line. The difference of acoustic intensity after passing the skull is very small (<5%) for 1 MHz and 5 MHz ultrasound after acoustic compensation, which enable a fair comparison between different methods.

Bottom Line: Electromyography (EMG) collected from tail muscles together with the motion response videos were analyzed for evaluating the stimulation effects.Our results indicate that 5 MHz ultrasound can successfully achieve neuro-stimulation.It provides a smaller stimulation region, which offers improved anatomical specificity for neuro-stimulation in a non-invasive manner.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.

ABSTRACT
Low frequency ultrasound (<1 MHz) has been demonstrated to be a promising approach for non-invasive neuro-stimulation. However, the focal width is limited to be half centimeter scale. Minimizing the stimulation region with higher frequency ultrasound will provide a great opportunity to expand its application. This study first time examines the feasibility of using high frequency (5 MHz) ultrasound to achieve neuro-stimulation in brain, and verifies the anatomical specificity of neuro-stimulation in vivo. 1 MHz and 5 MHz ultrasound stimulation were evaluated in the same group of mice. Electromyography (EMG) collected from tail muscles together with the motion response videos were analyzed for evaluating the stimulation effects. Our results indicate that 5 MHz ultrasound can successfully achieve neuro-stimulation. The equivalent diameter (ED) of the stimulation region with 5 MHz ultrasound (0.29 ± 0.08 mm) is significantly smaller than that with 1 MHz (0.83 ± 0.11 mm). The response latency of 5 MHz ultrasound (45 ± 31 ms) is also shorter than that of 1 MHz ultrasound (208 ± 111 ms). Consequently, high frequency (5 MHz) ultrasound can successfully activate the brain circuits in mice. It provides a smaller stimulation region, which offers improved anatomical specificity for neuro-stimulation in a non-invasive manner.

No MeSH data available.


Related in: MedlinePlus