Functional mapping of the motor cortex of the rat using transdural electrical stimulation

Fonoff, Erich Talamoni; Pereira, João Baptista Borges; Camargo, Leonardo Valente; Dale, Camila S.; Pagano, Rosana L.; Ballester, Gerson; Teixeira, Manoel Jacobsen

doi:10.1016/j.bbr.2009.03.018

Cited by 67 publications

(60 citation statements)

References 14 publications

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“…The aim is also in line with a recent observation that ultrasound-mediated neural simulation is an all-or-nothing event and not correlated with the magnitude of the EMG signal (23). Referencing the functional atlas obtained by transdural electrical stimulation on the motor cortex of the rat (30), the somatomotor area of the brain that elicits tail movement was located (midline, 2 mm posterior to the Bregma). The location of the sonication focus was guided to the area-of-interest using the visual guidance system presented in our previous work (31), and adjusted further by maneuvering the 3-axes platform within a 2 mm distance from the initial location.…”

Section: Methodsmentioning

confidence: 99%

Focused Ultrasound-mediated Non-invasive Brain Stimulation: Examination of Sonication Parameters

et al. 2014

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Background Transcranial focused ultrasound (FUS) has emerged as a new brain stimulation modality. The range of sonication parameters for successful brain stimulation warrants further investigation. Objective The objective of this study was to examine the range of FUS sonication parameters that minimize the acoustic intensity/energy deposition while successfully stimulating the motor brain area in Sprague-Dawley rats. Methods We transcranially administered FUS to the somatomotor area of the rat brain and measured the acoustic intensity that caused excitatory effects with respect to different pulsing parameters (tone-burst duration, pulse-repetition frequency, duty cycle, and sonication duration) at 350 and 650 kHz of fundamental frequency. Results We observed that motor responses were elicited at minimum threshold acoustic intensities (4.9–5.6 W/cm2 in spatial-peak pulse-average intensity; 2.5–2.8 W/cm2 in spatial-peak temporal-average intensity) in a limited range of sonication parameters, i.e. 1–5 ms of tone-burst duration, 50% of duty cycle, and 300 ms of sonication duration, at 350 kHz fundamental frequency. We also found that the pulsed sonication elicited motor responses at lower acoustic intensities than its equivalent continuous sonication. Conclusion Our results suggest that the pulsed application of FUS selectively stimulates specific brain areas-of-interest at an acoustic intensity that is compatible with regulatory safety limits on biological tissue, thus allowing for potential applications in neurotherapeutics.

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Section: Methodsmentioning

confidence: 99%

Focused Ultrasound-mediated Non-invasive Brain Stimulation: Examination of Sonication Parameters

et al. 2014

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“…We subsequently discovered, however, that these injections infringed upon the forelimb area, causing considerable labeling of CST axons that normally project to the cervical spinal cord. This labeling made it difficult to assess the sprouting of hindlimb CST fibers after SCI, and we therefore modified the injection coordinates based on an electrophysiological mapping study of the motor cortex [25] (new coordinates in cm with respect to bregma: 0.05 A/P, ± 0.10 M/L; 0.00 A/P, ± 0.10 M/L; 0.00 A/P, 0.0 M/L; -0.05 A/P, ± 0.10 M/L; -0.05 A/P, ± 0.15 M/L; -0.10 A/P, ± 0.10 M/L; -0.10 A/P, ± 0.15 M/L). BDA injections (Nanoject II, Drummond Scientific) were placed at 3 different depths (2.0 mm, 1.0 mm, 0.5 mm, 1 min each) for each injection site.…”

Section: Methodsmentioning

confidence: 99%

Inosine Enhances Axon Sprouting and Motor Recovery after Spinal Cord Injury

et al. 2013

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Although corticospinal tract axons cannot regenerate long distances after spinal cord injury, they are able to sprout collateral branches rostral to an injury site that can help form compensatory circuits in cases of incomplete lesions. We show here that inosine enhances the formation of compensatory circuits after a dorsal hemisection of the thoracic spinal cord in mature rats and improves coordinated limb use. Inosine is a naturally occurring metabolite of adenosine that crosses the cell membrane and, in neurons, activates Mst3b, a protein kinase that is part of a signal transduction pathway that regulates axon outgrowth. Compared to saline-treated controls, rats with dorsal hemisections that were treated with inosine showed three times as many synaptic contacts between corticospinal tract collaterals and long propriospinal interneurons that project from the cervical cord to the lumbar level. Inosine-treated rats also showed stronger serotonergic reinnervation of the lumbar cord than saline-treated controls, and performed well above controls in both open-field testing and a horizontal ladder rung-walking test. Inosine was equally effective whether delivered intracranially or intravenously, and has been shown to be safe for other indications in humans. Thus, inosine might be a useful therapeutic for improving outcome after spinal cord injury.

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“…Two burr holes were drilled over the right skull regions to the primary motor cortex of the right forelimb (AP: -1.5 mm from the bregma; ML: 4.0 mm with respect to the midline) and hindlimb (AP: 1.0 mm from the bregma; ML: 1.25 mm with respect to the midline) according to the functional brain mapping in rats (Fig. 1a) [14]. Two stainless steel bipolar epidural screw electrodes (Plastics One, Roanoke, VA, USA) with a 1.6-mm-diameter pole were implanted into the two burr holes.…”

Section: Electrophysiological Recordingsmentioning

confidence: 99%

Novel Use of Theta Burst Cortical Electrical Stimulation for Modulating Motor Plasticity in Rats

et al. 2015

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Various forms of cortical stimulation are capable of modulating motor cortical excitability through plasticity-like mechanisms and thus might have therapeutic potential for neurological diseases. To better understand the neural mechanism underlying the cortical neuromodulation effects and to enable translational research in rodent disease models, we developed a focused brain stimulation method using cortical electrical stimulation (CES) on the motor cortex in anesthetized rats. A specific stimulation scheme using theta burst stimulation (TBS) was then adopted to observe the facilitatory and inhibitory effects in motor cortical excitability. Adult male SpragueDawley rats were used for all experiments. Under urethane anesthesia, two epidural stainless steel screw electrodes were unilaterally implanted over the primary motor cortex targeting the forelimb area. Brachioradialis motor evoked potentials (MEPs) were obtained by single-pulse CES. Acute MEP changes were measured before and after intermittent and continuous TBS (iTBS and cTBS). For sham intervention, electrodes were implanted, but no TBS was delivered. To examine TBS-elicited plasticity responses, MEP amplitude was measured at baseline and for 30 min after iTBS or cTBS. The MEPs were significantly enhanced immediately after iTBS (p = 0.001) and remained enhanced for 30 min (p \ 0.001) compared to the baseline MEP. Similarly, the MEPs were suppressed in 5 min (p = 0.035) and lasted for 30 min or more (p \ 0.001) after cTBS. No effect was noted on the MEP magnitude in rats under sham stimulation (p [ 0.05). The developed TBS scheme uses the focused CES method to produce consistent, rapid, and controllable electrophysiological changes in the motor cortex. In particular, the cortical plasticity can be modulated in rat models via the CES-TBS protocols. These findings may have translational relevance for establishing new therapeutic CES applications in neurological disorders.

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Functional mapping of the motor cortex of the rat using transdural electrical stimulation

Cited by 67 publications

References 14 publications

Focused Ultrasound-mediated Non-invasive Brain Stimulation: Examination of Sonication Parameters

Focused Ultrasound-mediated Non-invasive Brain Stimulation: Examination of Sonication Parameters

Inosine Enhances Axon Sprouting and Motor Recovery after Spinal Cord Injury

Novel Use of Theta Burst Cortical Electrical Stimulation for Modulating Motor Plasticity in Rats

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