Transcranial focused ultrasound to human rIFG improves response inhibition through modulation of the P300 onset latency

Integrating data mining with transcranial focused ultrasound to refine neuralgia treatment strategies

BACKGROUND

Neuralgia and other neuropathic pain are difficult to treat owing to their complicated etiology and a wide variety of responses to treatment. The novel neuromodulation technology transcranial focused ultrasound (tFUS) has intriguing implications in targeted non-invasive brain stimulation. Patient-specific variables and neurological processes must be better understood to enhance tFUS for personalized therapy.

METHODS

In this research, a Machine Learning based Transcranial Focused Ultrasound Personalized Model (ML-tFUSPM) has been proposed to treat neuralgia by combining tFUS with data mining for personalized therapy. Data mining algorithms can examine patient demographics, pain factors, imaging data, and therapy outcomes to uncover response patterns and treatment predictors. According to these results, tFUS may be tailored to each patient by targeting brain regions involved in pain perception and control.

RESULTS

Initial studies show that data-driven models and tFUS enhance therapeutic efficacy, side effects, and accuracy. This collaborative endeavor uses data analytics and neuromodulation to customize neuralgia treatment. The new model's emphasis on targeted treatments and predictive analytics gives clinicians evidence-based tools to manage pain more effectively and personally, which might transform the industry.

COMPARATIVE ANALYSIS

The experimental results show that the proposed method has a high accuracy ratio of 97 % compared to other methods.

CONCLUSION

According to this study, computational principles and cutting-edge technology may lead to game-changing neurology and pain management advances.

Probing phased-array focused ultrasound transducers using realistic 3D in-silico trabecular skull models: a numerical study

Transcranial focused ultrasound (tFUS) is an emerging neuromodulation technology with transformative potential for brain disease therapies. This study explores how the trabecular structure of the human skull affects the performance of multi-element tFUS transducers. Numerical simulations were conducted using realistic 3D skull models with varying porosities (0 %, 50 %, and 60 %), comparing the pressure fields generated by two geometrically distinct 96-elements phased-array transducers (f-number = 0.8 -transducer 1- and f-number = 1.1 -transducer 2-). Pressure distribution maps and -6dB isosurfaces were analyzed to quantify focal and scattered volumes, as well as focus shifts. Results demonstrate that porous skull models significantly impact the pressure field, introducing scattering and hotspots outside the target area, that are undetectable with non-porous models. Both transducers exhibit focus shifts along the propagation axis, with transducer 2 showing lower selectivity and nearly 450 % and 1000 % increased scattering compared to transducer 1 in the porous models. These findings emphasize the necessity of incorporating such models in tFUS simulations to improve the accuracy of pressure predictions and device performance. Our results highlight the critical importance of accurately modelling skull porosity in tFUS simulations. Using simplified non-porous models can obscure scattering effects and lead to distorted predictions of transducer performance. This work also demonstrates how generating in-silico porous models with varying porosity allows for testing the reliability and robustness of a numerically designed transducer. It also provides valuable insights into optimizing transducer design ultimately improving target precision while mitigating unintended sonication, laying the groundwork for safer and more effective tFUS therapies.

Multiple insular-prefrontal pathways underlie perception to execution during response inhibition in humans

Inhibiting prepotent responses in the face of external stop signals requires complex information processing, from perceptual to control processing. However, the cerebral circuits underlying these processes remain elusive. In this study, we used neuroimaging and brain stimulation to investigate the interplay between human brain regions during response inhibition at the whole-brain level. Magnetic resonance imaging suggested a sequential four-step processing pathway: initiating from the primary visual cortex (V1), progressing to the dorsal anterior insula (daINS), then involving two essential regions in the inferior frontal cortex (IFC), namely the ventral posterior IFC (vpIFC) and anterior IFC (aIFC), and reaching the basal ganglia (BG)/primary motor cortex (M1). A combination of ultrasound stimulation and time-resolved magnetic stimulation elucidated the causal influence of daINS on vpIFC and the unidirectional dependence of aIFC on vpIFC. These results unveil asymmetric pathways in the insular-prefrontal cortex and outline the macroscopic cerebral circuits for response inhibition: V1→daINS→vpIFC/aIFC→BG/M1.

Dynamic changes in human brain connectivity following ultrasound neuromodulation

Non-invasive neuromodulation represents a major opportunity for brain interventions, and transcranial focused ultrasound (FUS) is one of the most promising approaches. However, some challenges prevent the community from fully understanding its outcomes. We aimed to address one of them and unravel the temporal dynamics of FUS effects in humans. Twenty-two healthy volunteers participated in the study. Eleven received FUS in the right inferior frontal cortex while the other 11 were stimulated in the right thalamus. Using a temporal dynamic approach, we compared resting-state fMRI seed-based functional connectivity obtained before and after FUS. We also assessed behavioural changes as measured with a task of reactive motor inhibition. Our findings reveal that the effects of FUS are predominantly time-constrained and spatially distributed in brain regions functionally connected with the directly stimulated area. In addition, mediation analysis highlighted that FUS applied in the right inferior cortex was associated with behavioural alterations which was directly explained by the applied acoustic pressure and the brain functional connectivity change we observed. Our study underscored that the biological effects of FUS are indicative of behavioural changes observed more than an hour following stimulation and are directly related to the applied acoustic pressure.

Transcranial Focused Ultrasound Neuromodulation in Psychiatry: Main Characteristics, Current Evidence, and Future Directions

Non-invasive brain stimulation (NIBS) techniques are designed to precisely and selectively target specific brain regions, thus enabling focused modulation of neural activity. Among NIBS technologies, low-intensity transcranial focused ultrasound (tFUS) has emerged as a promising new modality. The application of tFUS can safely and non-invasively stimulate deep brain structures with millimetric precision, offering distinct advantages in terms of accessibility to non-cortical regions over other NIBS methods. However, to date, several tFUS aspects still need to be characterized; furthermore, there are only a handful of studies that have utilized tFUS in psychiatric populations. This narrative review provides an up-to-date overview of key aspects of this NIBS technique, including the main components of a tFUS system, the neuronavigational tools used to precisely target deep brain regions, the simulations utilized to optimize the stimulation parameters and delivery of tFUS, and the experimental protocols employed to evaluate the efficacy of tFUS in psychiatric disorders. The main findings from studies in psychiatric populations are presented and discussed, and future directions are highlighted.

A review of functional neuromodulation in humans using low-intensity transcranial focused ultrasound

Transcranial ultrasonic neuromodulation is a rapidly burgeoning field where low-intensity transcranial focused ultrasound (tFUS), with exquisite spatial resolution and deep tissue penetration, is used to non-invasively activate or suppress neural activity in specific brain regions. Over the past decade, there has been a rapid increase of tFUS neuromodulation studies in healthy humans and subjects with central nervous system (CNS) disease conditions, including a recent surge of clinical investigations in patients. This narrative review summarized the findings of human neuromodulation studies using either tFUS or unfocused transcranial ultrasound (TUS) reported from 2013 to 2023. The studies were categorized into two separate sections: healthy human research and clinical studies. A total of 42 healthy human investigations were reviewed as grouped by targeted brain regions, including various cortical, subcortical, and deep brain areas including the thalamus. For clinical research, a total of 22 articles were reviewed for each studied CNS disease condition, including chronic pain, disorder of consciousness, Alzheimer's disease, Parkinson's disease, depression, schizophrenia, anxiety disorders, substance use disorder, drug-resistant epilepsy, and stroke. Detailed information on subjects/cohorts, target brain regions, sonication parameters, outcome readouts, and stimulatory efficacies were tabulated for each study. In later sections, considerations for planning tFUS neuromodulation in humans were also concisely discussed. With an excellent safety profile to date, the rapid growth of human tFUS research underscores the increasing interest and recognition of its significant potential in the field of non-invasive brain stimulation (NIBS), offering theranostic potential for neurological and psychiatric disease conditions and neuroscientific tools for functional brain mapping.