Project background

Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are two widely used non-invasive methods to modulate the activity of a given brain region and, thereby, study its function in humans [1-2]. Very recently, it was suggested that transcranial focused ultrasounds (TFUS) can also be used as a non-invasive mean to modulate cortical activity in humans [3-7]. The fact that ultrasounds (US) can exert a neuromodulatory effect is well established, and there is a large body of evidence showing that US can directly modulate the activity of peripheral nerves, elicit action potentials in hippocampal slices, and modulate cortical activity in animals [8] At low intensities and for short exposure times, tissue heating and tissue damage do not occur. The mechanism of action of TFUS is thought to be related to an effect of the acoustic pressure waves on mechanically-sensitive structures such as cell membranes and ion channels, thereby altering ionic flux [9]. US could also exert an effect on the mobility of synaptic vesicles, thereby modulating synaptic transmission.

Most importantly, TFUS could overcome some of the important drawbacks of TMS and tDCS. Therefore, TFUS could open new perspectives for research in human neuroscience.

General objective of the project

The general objective of the project is to develop a novel approach based on transcranial focused ultrasound (TFUS) and on the combination of TFUS with electroencephalography (EEG) to characterize and to investigate the interdependencies between the different brain regions involved in human pain perception.

References

[1] Fregni F, Pascual-Leone A. 2007. Technology insight: noninvasive brain stimulation in neurology-perspectives on the therapeutic potential of rTMS and tDCS. Nat Clin Pract Neurol 3:383-393.

[2] Walsh V, Cowey A. 2000. Transcranial magnetic stimulation and cognitive neuroscience. Nat Rev Neurosci 1:73-79.

[3] Legon W, Sato TF, Opitz A, Mueller J, Barbour A, Williams A, Tyler WJ. 2014. Transcranial focused ultrasound modulates the activity of primary somatosensory cortex in humans. Nat Neurosci 17:322-329.

[4] Lee W, Kim H, Jung Y, Song I-U, Chung Y A, Yoo S-S. 2015. Image-guided transcranial focused ultrasound stimulates human primary somatosensory cortex. Sci Rep 5:8743

[5] Lee W, Kim H-C, Jung Y, Chung Y A, Song I-U, Lee J-H &Yoo S-S. 2016. Transcranial focused ultrasound stimulation of human primary visual cortex.  Sci Rep 6:34026

[6] Lee W, Chung YA, Jung Y, Song IU, Yoo SS. 2016. Simultaneous acoustic stimulation of human primary and secondary somatosensory cortices using transcranial focused ultrasound. BMC Neurosci. 17:68.

[7] Lee W, Kim S, Kim B, Lee C, Chung YA, Kim L, Yoo SS. 2017. Non-invasive transmission of sensorimotor information in humans using an EEG/focused ultrasound brain-to-brain interface. Plos One 12:e0178476

[8] Tyler WJ. 2011. Noninvasive neuromodulation with ultrasound? A continuum mechanics hypothesis. Neuroscientist 17:25-36.

[9] Velling VA, Shklyaruk SP. 1988. Modulation of the functional state of the brain with the aid of focused ultrasonic action. Neurosci Behav Physiol 18:369-375.