Improved methods of noninvasively modulating human brain function are needed. Here we probed the influence of transcranial focused ultrasound (tFUS) targeted to the human primary somatosensory cortex (S1) on sensory-evoked brain activity and sensory discrimination abilities. The lateral and axial spatial resolution of the tFUS beam implemented were 4.9 mm and 18 mm, respectively. Electroencephalographic recordings showed that tFUS significantly attenuated the amplitudes of somatosensory evoked potentials elicited by median nerve stimulation. We also found that tFUS significantly modulated the spectral content of sensory-evoked brain oscillations. The changes produced by tFUS on sensory-evoked brain activity were abolished when the acoustic beam was focused 1 cm anterior or posterior to S1. Behavioral investigations showed that tFUS targeted to S1 enhanced performance on sensory discrimination tasks without affecting task attention or response bias. We conclude that tFUS can be used to focally modulate human cortical function.
The nexin–dynein regulatory complex (N-DRC) is implicated in the control of dynein activity as a structural component of the nexin link. This study identifies several new subunits of the N-DRC and demonstrates for the first time that it forms a discrete biochemical complex that maintains outer doublet integrity and regulates microtubule sliding.
Transcranial focused ultrasound (tFUS) has proven capable of stimulating cortical tissue in humans. tFUS confers high spatial resolutions with deep focal lengths and as such, has the potential to noninvasively modulate neural targets deep to the cortex in humans. We test the ability of single-element tFUS to noninvasively modulate unilateral thalamus in humans. Participants (N = 40) underwent either tFUS or sham neuromodulation targeted at the unilateral sensory thalamus that contains the ventro-posterior lateral (VPL) nucleus of thalamus. Somatosensory evoked potentials (SEPs) were recorded from scalp electrodes contralateral to median nerve stimulation. Activity of the unilateral sensory thalamus was indexed by the P14 SEP generated in the VPL nucleus and cortical somatosensory activity by subsequent inflexions of the SEP and through time/frequency analysis. Participants also under went tactile behavioral assessment during either the tFUS or sham condition in a separate experiment. A detailed acoustic model using computed tomography (CT) and magnetic resonance imaging (MRI) is also presented to assess the effect of individual skull morphology for single-element deep brain neuromodulation in humans. tFUS targeted at unilateral sensory thalamus inhibited the amplitude of the P14 SEP as compared to sham. There is evidence of translation of this effect to time windows of the EEG commensurate with SI and SII activities. These results were accompanied by alpha and beta power attenuation as well as time-locked gamma power inhibition. Furthermore, participants performed significantly worse than chance on a discrimination task during tFUS stimulation.
Transcranial focused ultrasound is an emerging form of non-invasive neuromodulation that uses acoustic energy to affect neuronal excitability. The effect of ultrasound on human motor cortical excitability and behavior is currently unknown. We apply ultrasound to the primary motor cortex in humans using a novel simultaneous transcranial ultrasound and magnetic stimulation 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). 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). 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. Ultrasound also 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.
Wind and solar industries have grown rapidly in recent years but they still supply only a small fraction of global electricity. The continued growth of these industries to levels that significantly contribute to climate change mitigation will depend on whether they can compete against alternatives that provide high-value energy on demand. Energy storage can transform intermittent renewables for this purpose but cost improvement is needed. Evaluating diverse storage technologies on a common scale has proved a major challenge, however, owing to their widely varying performance along the two dimensions of energy and power costs. Here we devise a method to compare storage technologies, and set cost improvement targets. Some storage technologies today are shown to add value to solar and wind energy, but cost reduction is needed to reach widespread profitability. The optimal cost improvement trajectories, balancing energy and power costs to maximize value, are found to be relatively location invariant, and thus can inform broad industry and government technology development strategies. W ind and solar energy technologies have attractive attributes including their zero direct carbon and other air-pollutant emissions (during operation) 1,2 , their low water withdrawal and consumption requirements 3 , the speed with which they can be installed 4 , and the flexibility in the scale of their installations 5,6 . Innovation in these technologies has taken off in the past two decades 7 . Levelized electricity costs for both technologies have been dropping over the past few decades, with photovoltaics costs falling exceptionally quickly, by two orders of magnitude over the past 40 years 8,9 . The installed bases of solar and wind have grown markedly in recent decades, each at approximately 30% per year on average over the past 30 years, but together still supply only a few per cent of global electricity 9 . Although the global solar and wind energy resources are large, these technologies do not measurably contribute to climate change mitigation at current installations levels.A variety of government policy-based incentives have supported the growth in solar and wind energy technologies in recent decades 10,11 , but continued, rapid growth to levels that can help meet climate change mitigation goals will depend on whether the adoption of wind and solar can be made self-sustaining. Low-cost storage can play a pivotal role by converting intermittent wind and solar energy resources, which fluctuate over time with changes in weather, the diurnal cycle, and seasons 12 , to electricity on demand that can be sold when most profitable, thereby increasing the value and attractiveness of these technologies to investors 13,14 . However, storage costs need to improve to achieve sizable adoption 15,16 . Quantifying the cost reduction needed has proved challenging and is the topic of this paper.A range of stationary, large-scale energy storage technologies are in development 17 . These technologies have widely varying power and energy costs. S...
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