Biology subjects

Mueller, J. K.

Publications and source records attributed to Mueller, J. K..

3 recordsLinked to original sources

bioRxiv2018

Safety of transcranial focused ultrasound for human neuromodulation

BackgroundLow intensity transcranial focused ultrasound (tFUS) is a new method of non-invasive neuromodulation that uses acoustic energy to affect neuronal excitability. tFUS offers high spatial resolution and adjustable focal lengths for precise neuromodulation of discrete regions in the human brain. Before the full potential of low intensity ultrasound for research and clinical application can be investigated, data on the safety of this technique is indicated.\n\nObjective/HypothesisTo provide an initial evaluation of the safety of tFUS for human neuromodulation through participant report and neurological assessment surrounding pilot investigation of tFUS for neuromodulation.\n\nMethodsParticipants (N = 120) that were enrolled in one of seven human ultrasound neuromodulation studies at the University of Minnesota (2015 - 2017) were queried to complete a follow-up Participant Report of Symptoms questionnaire assessing their self-reported experience and tolerance to participation in tFUS research and the perceived relation of symptoms to tFUS.\n\nResultsA total of 64/120 participant (53%) responded to follow-up requests to complete the Participant Report of Symptoms questionnaire. During the conduct of the seven studies in this report, none of the participants experienced serious adverse effects. From the post-hoc assessment of safety using the questionnaire, 7/64 reported mild to moderate symptoms, that were perceived as possibly or probably related to participation in tFUS experiments. These reports included neck pain, problems with attention, muscle twitches and anxiety. The most common unrelated symptoms included sleepiness and neck pain. There were initial transient reports of mild neck pain, scalp tingling and headache that were extinguished upon follow-up. No new symptoms were reported upon follow up out to 1 month.\n\nConclusions(s)To date, in the literature and including this report, no serious adverse events have been reported as a result of low intensity tFUS for human neuromodulation. Here, we report new data on minor transient events. As currently employed with the parameters used in the studies in this report, tFUS looks to be a safe form of transient neuromodulation in humans.

neuroscience↗

bioRxiv2018

Effects of transcranial focused ultrasound on human primary motor cortex using 7T fMRI

BackgroundTranscranial focused ultrasound (tFUS) is a new non-invasive neuromodulation technique that uses mechanical energy to modulate neuronal excitability with high spatial precision. tFUS has been shown to be capable of modulating EEG brain activity in humans that is spatially restricted, and here, we use 7T MRI to extend these findings. We test the effect of tFUS on 7T BOLD fMRI signals from individual finger representations in the human primary motor cortex (M1) and connected cortical motor regions. Participants (N = 5) performed a cued finger tapping task in a 7T MRI scanner with their thumb, index, and middle fingers to produce a BOLD signal for individual M1 finger representations during either tFUS or sham neuromodulation to the thumb representation.\n\nResultsResults demonstrated a statistically significant increase in activation volume of the M1 thumb representation for the tFUS condition as compared to sham. No differences in percent BOLD changes were found. This effect was spatially confined as the index and middle finger M1 finger representations did not show similar significant changes in either percent change or activation volume. No effects were seen during tFUS to M1 in the supplementary motor area (SMA) or the dorsal premotor cortex (PMd).\n\nConclusionsSingle element tFUS can be paired with high field MRI that does not induce significant artifact. tFUS increases activation volumes of the targeted finger representation that is spatially restricted within M1 but does not extend to functionally connected motor regions.

neuroscience↗

bioRxiv2018

Transcranial focused ultrasound neuromodulation of the human primary motor cortex

Transcranial focused ultrasound is a form of non-invasive neuromodulation that uses acoustic energy to affect neuronal excitability. The effect of ultrasound on human motor cortical excitability is currently unknown. We apply ultrasound to the primary motor cortex in humans using a novel transcranial ultrasound and magnetic stimulation (TUMS) paradigm that allows for concurrent and concentric ultrasound stimulation with transcranial magnetic stimulation (TMS). This allows for non-invasive inspection of the effect of ultrasound on motor neuronal excitability using the motor evoked potential (MEP) generated by TMS. We test the effect of ultrasound on single pulse MEP recruitment curves and paired pulse protocols including short interval intracortical inhibition (SICI) and intracortical facilitation (ICF). We also test the longevity of the effect and the effect of ultrasound on the cortical silent period in a small sub-sample of participants. In addition, we test the effect of ultrasound to motor cortex on a stimulus response reaction time task. Results show ultrasound inhibits the amplitude of single-pulse MEPs and attenuates intracortical facilitation but does not affect intracortical inhibition. Early evidence suggests that ultrasound does not affect cortical silent period duration and that the duration of inhibition may be related to the duration of stimulation. Finally, ultrasound reduces reaction time on a simple stimulus response task. This is the first report of the effect of ultrasound on human motor cortical excitability and motor behavior and confirms previous results in the somatosensory cortex that ultrasound results in effective neuronal inhibition that confers a performance advantage.

neuroscience↗