Instruct: Identify the main category of Biorxiv papers based on the titles and abstracts
Query: Multi-locus transcranial magnetic stimulation system for electronically targeted brain stimulation BackgroundTranscranial magnetic stimulation (TMS) allows non-invasive stimulation of the cortex. In multi-locus TMS (mTMS), the stimulating electric field (E-field) is controlled electronically without coil movement by adjusting currents in the coils of a transducer.

ObjectiveTo develop an mTMS system that allows adjusting the location and orientation of the E-field maximum within a cortical region.

MethodsWe designed and manufactured a planar 5-coil mTMS transducer to allow controlling the maximum of the induced E-field within a cortical region approximately 30 mm in diameter. We developed electronics with a design consisting of independently controlled H-bridge circuits to drive up to six TMS coils. To control the hardware, we programmed software that runs on a field-programmable gate array and a computer. To induce the desired E-field in the cortex, we developed an optimization method to calculate the currents needed in the coils. We characterized the mTMS system and conducted a proof-of-concept motor-mapping experiment on a healthy volunteer. In the motor mapping, we kept the transducer placement fixed while electronically shifting the E-field maximum on the precentral gyrus and measuring electromyography from the contralateral hand.

ResultsThe transducer consists of an oval coil, two figure-of-eight coils, and two four-leaf-clover coils stacked on top of each other. The technical characterization indicated that the mTMS system performs as designed. The measured motor evoked potential amplitudes varied consistently as a function of the location of the E-field maximum.

ConclusionThe developed mTMS system enables electronically targeted brain stimulation within a cortical region.
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The categories of this paper are: evolutionary
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The categories of this paper are: behavior
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The categories of this paper are: cell
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The categories of this paper are: bioinformatics
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The categories of this paper are: cancer
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The categories of this paper are: paleontology
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The categories of this paper are: genetics
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The categories of this paper are: toxicology
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The categories of this paper are: pharmacology
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The categories of this paper are: ecology
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The categories of this paper are: synthetic
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The categories of this paper are: communication
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The categories of this paper are: developmental
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The categories of this paper are: plant
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The categories of this paper are: education
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The categories of this paper are: cognition