12 research outputs found
A new handheld electromagnetic cortical stimulator for brain mapping during open skull neurosurgery: a feasibility study
Transcranial magnetic stimulations have provided invaluable tools for investigating nervous system functions in a preoperative context; in this paper we propose an innovative tool to extend the magnetic stimulation to an open skull context as a promising approach to map the brain cortex. The present gold standard for intraoperative functional mapping of the brain cortex, the direct brain stimulation, has a low spatial resolution and limited penetration and focusing capabilities. The magnetic stimulatory device that we present, is designed to overcome these limitations, while working with low currents and voltages. In the present work we propose an early study of feasibility, in which the possibility of exploiting a train of fast changing magnetic fields to reach the neuron's current thresholds is investigated. Measurements of electric field intensity at different distances from the coil, showed that the magnetic stimulator realized is capable of delivering an electric field on a loop of wire theoretically sufficient to evoke neuron's action potential, thus showing the approach' feasibility
Electric field and current density distribution in an anatomical head model during transcranial direct current stimulation for tinnitus treatment
Exposure of high resolution fetuses in advanced pregnant woman models at different stages of pregnancy to uniform magnetic fields at the frequency of 50 Hz
Three-dimensional laser scanning and reconstruction of ear canal impresions for optimal design of hearing aid shells
Quantitative analysis of cochlear active mechanisms in tinnitus subjects with normal hearing sensitivity: Time-frequency analysis of transient evoked otoacoustic emissions and contralateral suppression.
Modelling the electric field and the current density generated by cerebellar transcranial DC stimulation in humans
Objective: Transcranial Direct Current Stimulation (tDCS) over the cerebellum (or cerebellar tDCS) modulates working memory, changes cerebello-brain interaction, and affects locomotion in humans. Also, the use of tDCS has been proposed for the treatment of disorders characterized by cerebellar dysfunction. Nonetheless, the electric field (E) and current density (J) spatial distributions generated by cerebellar tDCS are unknown. This work aimed to estimate E and J distributions during cerebellar tDCS. Methods: Computational electromagnetics techniques were applied in three human realistic models of different ages and gender. Results: The stronger E and J occurred mainly in the cerebellar cortex, with some spread (up to 4%) toward the occipital cortex. Also, changes by \ub11. cm in the position of the active electrode resulted in a small effect (up to 4%) in the E and J spatial distribution in the cerebellum. Finally, the E and J spreads to the brainstem and the heart were negligible, thus further supporting the safety of this technique. Conclusions: Despite inter-individual differences, our modeling study confirms that the cerebellum is the structure mainly involved by cerebellar tDCS. Significance: Modeling approach reveals that during cerebellar tDCS the current spread to other structures outside the cerebellum is unlike to produce functional effects