References of "D'Ostilio, Kevin"
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See detailThe network model of depression as a basis for new therapeutic strategies for treating major depressive disorder in Parkinson’s disease
D'Ostilio, Kevin ULg; Garraux, Gaëtan ULg

in Frontiers in Human Neuroscience (in press)

The high prevalence of major depressive disorder in people with Parkinson's disease, its negative impact on health-related quality of life and the low response rate to conventional pharmacological ... [more ▼]

The high prevalence of major depressive disorder in people with Parkinson's disease, its negative impact on health-related quality of life and the low response rate to conventional pharmacological therapies call to seek innovative treatments. Here, we review the new approaches for treating major depressive disorder in patients with Parkinson's disease within the framework of the network model of depression. According to this model, major depressive disorder reflects maladaptive neuronal plasticity. Non-invasive brain stimulation using high frequency repetitive transcranial magnetic stimulation over the prefrontal cortex has been proposed as a feasible and effective strategy with minimal risk. The neurobiological basis of its therapeutic effect may involve neuroplastic modifications in limbic and cognitive networks. However, the way this networks reorganize might be strongly influenced by the environment. To address this issue, we propose a combined strategy that includes non-invasive brain stimulation together with cognitive and behavioral interventions. [less ▲]

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See detailEffects of 10Hz and 20Hz transcranial alternating current stimulation on automatic motor control
Cappon, Davide; D'Ostilio, Kevin ULg; Garraux, Gaëtan ULg et al

in Brain Stimulation (in press)

Background: Automatic motor inhibition is an important and adaptive process through which an activated motor plan is suppressed if the movement is not intended to be executed. Neuronal networks are ... [more ▼]

Background: Automatic motor inhibition is an important and adaptive process through which an activated motor plan is suppressed if the movement is not intended to be executed. Neuronal networks are characterized by oscillatory activity. In the brain, a large variety of rhythms have been described that differ in their frequency, origin and reactivity to changes in task demands. Recent studies have demonstrated that active cortical networks are susceptible to weak sinusoidal perturbations of exogenous electric fields. Objective/Hypothesis: The aim of this study was to investigate the frequency-specific effect of transcranial alternate current stimulation (tACS) over the automatic control of movement in healthy volunteers. We hypothesized that applying two different tACS frequencies during a visuo-motor task would result in different behavioural effects and in diverse modulation of cortical excitability. Methods: In this study we used tACS to interact non-invasively with the ongoing task-related oscillatory activity. Stimulation was delivered at alpha (10 Hz) and beta (20 Hz) frequency over the supplementary motor area and the primary motor cortex (SMA-M1) connections, which are part of the BG-cortical motor loop, during the execution of the subliminal masked prime task. We measured the effects on task performance and on motor cortex corticospinal excitability by means of motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS). Results: Results indicate a specific effect of 10 and 20-Hz tACS on functional inhibition in the SMA-M1 circuit. Behaviorally there is an interference in task-related automatic inhibition: 10 Hz tACS reduced the automatic inhibition. In contrast 20 Hz tACS increased the automatic inhibition. At a neurophysiological level there is a modulation in excitability of M1: 20 Hz tACS reduced MEP amplitudes, whereas there was no change after 10 Hz tACS. Conclusion(s): The current study provides novel evidence that automatic mechanisms of motor behaviour can be modulated by imposing synchronized electrical oscillatory activity upon motor cortical regions. Our study has important implications for cognitive neuroscience studies suggesting that the use tACS might offer the possibility to demonstrate a causal link between endogenous brain oscillations, specific exogenous alternate current frequencies and specific cognitive processes. [less ▲]

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See detailAnodal transcranial direct stimulation (tDCS) targeting the anterior cingulate gyrus for the preventive treatment of chronic cluster headache: a proof of concept trial.
MAGIS, Delphine ULg; D'Ostilio, Kevin ULg; Cosseddu, Anna et al

Poster (2016, April)

Background There is a need for better treatments in chronic cluster headache (CCH). In responders to percutaneous occipital nerve stimulation, the subgenual anterior cingulate gyrus (sACG) was found ... [more ▼]

Background There is a need for better treatments in chronic cluster headache (CCH). In responders to percutaneous occipital nerve stimulation, the subgenual anterior cingulate gyrus (sACG) was found hypermetabolic (Magis et al. 2011). We reasoned that activation of this area by transcranial neurostimulation could be effective in CCH. Aim To explore the preventive effect of anodal (i.e. activating) transcranial direct current stimulation (tDCS) targeting the anterior cingulate gyrus in CCH patients. Method & subjects Difficult-to-treat CCH patients with a stable preventive drug regimen applied tDCS (2mA) interictally in 20-minute daily sessions for 4 weeks with the anode positioned over the forehead (FpZ), the cathode over the C7 spinous process. Therapeutic effects were monitored with paper diaries. Results Nineteen patients were enrolled up to now. In 13 patients who completed the trial, mean weekly attack frequency decreased by 38% after 4 weeks of daily stimulation (W-test: p = 0.002). The 50% responder rate was 54%. Patients (n=12) reported an improvement in headache impact, as shown by 5-point decrease in the mean HIT-6 score (from 67 to 62, p = 0.02). In 10 patients who were followed up after the treatment period, the benefit remained stable up to 4 weeks after the last stimulation. The first 3 enrolled patients had superficial skin burns under the adhesive cathode electrode. Sponge electrodes were therefore used in all subsequent patients without any adverse effect. Conclusion Anodal tDCS targeting the anterior cingulate gyrus seems promising for the preventive treatment of chronic cluster headache as suggested by this ongoing proof-of-concept trial. Use of adhesive electrodes is not recommended. [less ▲]

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See detailNon-invasive vagus nerve stimulation with the gammaCore® in healthy subjects: is there electrophysiological evidence for activation of vagal afferents ?
Schoenen, Jean ULg; NONIS, Romain ULg; D'Ostilio, Kevin ULg et al

Poster (2016, April)

Abstract: Background Non-invasive vagus nerve stimulation (nVNS) with the gammaCore® improves migraine and cluster headache. Animal experiments suggest that nVNS acts via stimulation of vagal afferents ... [more ▼]

Abstract: Background Non-invasive vagus nerve stimulation (nVNS) with the gammaCore® improves migraine and cluster headache. Animal experiments suggest that nVNS acts via stimulation of vagal afferents, but proof in humans is lacking. Vagal somatosensory evoked potentials (vSEP) are identified after invasive VNS or transcutaneous stimulation of auricular vagal branches, but late components could be muscle artifacts. Objective To search in healthy volunteers for reliable vSEP during nVNS with the gammaCore® Methods In 12 healthy subjects (7males) evoked potentials were recorded at A1/A2 (ref Cz) and C3/C4 (ref F3/F4) during 2-minute stimulation over left/right cervical vagus nerve with the gammaCore® (25Hz, 6-24V) and during stimulation over the inner tragus with a monopolar stimulator (2Hz, 50 stimuli, mean intensity 8mA). Results We identified 3 reproducible peaks P1, N1, P2 in 10 patients on the side of the gammaCore® stimulation at mean latencies of 2.05ms, 5.20ms and 9.13ms. P1-N1 amplitude increased significantly (p<0.01) with increasing voltage from 0.04μV to 0.52μV (C3/C4) and from 0.13µV to 2.04μV (A1/A2) respectively at 10V and 30V. Inner tragus stimulation elicited P1, N1, P2 peaks with shorter mean latencies (2.21ms, 3.72ms, 5.71ms) and a mean P1-N1 amplitude (A1/A2) of 5.0µV. When the gammaCore® was placed over the sternocleidomastoid muscle, there were no reproducible evoked potentials. Conclusion Non-invasive transcutaneous stimulation of the cervical vagus nerve with the gammaCore® elicits evoked potentials similar to those found with implanted electrodes or stimulation of Arnold’s nerve in the outer ear. The gammaCore®-evoked potentials increase in amplitude with stimulation intensity and disappear when the stimulator is positioned over neck muscles, suggesting that they are not muscle artifacts. Their short latency is compatible with their generation at the level of the foramen jugulare. The therapeutic effects reported with the gammaCore® in primary headaches can thus be mediated by genuine activation of vagus nerve afferents. [less ▲]

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See detailEffect of coil orientation on strength-duration time constant and I-wave activation with controllable pulse parameter transcranial magnetic stimulation
D'Ostilio, Kevin ULg; Goetz, Stefan; Hannah, Ricci et al

in Clinical Neurophysiology (2016), 1

Objective: To compare the strength-duration (S-D) time constants of motor cortex structures activated by current pulses oriented posterior-anterior (PA) or anterior-posterior (AP) across the central ... [more ▼]

Objective: To compare the strength-duration (S-D) time constants of motor cortex structures activated by current pulses oriented posterior-anterior (PA) or anterior-posterior (AP) across the central sulcus. Methods: Motor threshold and input–output curve, along with motor evoked potential (MEP) latencies, of first dorsal interosseus were determined at pulse widths of 30, 60, and 120 μs using a controllable pulse parameter (cTMS) device, with the coil oriented PA or AP. These were used to estimate the S-D time constant and we compared with data for responses evoked by cTMS of the ulnar nerve at the elbow. Results: The S-D time constant with PA was shorter than for AP stimulation (230.9 ± 97.2 vs. 294.2 ± 90.9 us; p<0.001). These values were similar to those calculated after stimulation of ulnar nerve (197 ± 47us). MEP latencies to AP, but not PA stimulation were affected by pulse width, showing longer latencies following short duration stimuli. Conclusion: PA and AP stimuli appear to activate the axons of neurons with different time constants. Short duration AP pulses are more selective than longer pulses in recruiting longer latency corticospinal output. [less ▲]

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See detailCerebral FDG uptake changes with supraorbital transcutaneous electrical stimulation for episodic migraine prevention
D'Ostilio, Kevin ULg; Thibaut, Aurore ULg; Laureys, Steven ULg et al

Conference (2015, May)

Background: A recent multicentre RCT has shown that supraorbital transcutaneous stimulation (STS) targeting branches of the ophtalmic nerve with the Cefaly® device is effective as a preventive therapy for ... [more ▼]

Background: A recent multicentre RCT has shown that supraorbital transcutaneous stimulation (STS) targeting branches of the ophtalmic nerve with the Cefaly® device is effective as a preventive therapy for migraine (Schoenen et al., Neurology 2013). However, the mechanisms of action in the central nervous system remain unknown. Here, we conducted voxel-based analyses of [18]FDG-PET to evaluate metabolic changes immediately after the first STS session and after 3 months of treatment in patients with migraine. Methods: Twenty-eight subjects participated in the experiment: 14 patients with episodic migraine (ICHD3 beta criteria) and 14 age-matched controls. Healthy volunteers underwent only one [18]FDG-PET scan whereas patients were scanned at baseline, directly after a first session of STS and after 3 months of daily treatment. Results: Compliant patients showed a significant decrease in the number of attacks (p = 0.03). When compared to controls, patients (n = 14) at baseline were hypometabolic in the fronto-temporal regions (p < 0.001), especially in the orbitofrontal (OFC) and perigenual anterior cingulate cortex. OFC hypometabolism was not correlated with medication intake. In compliant patients, daily STS for 3 months was followed by a normalization of the fronto-temporal hypometabolism (p< 0.001; OFC: pFWE<0.01). Conclusion: Our study suggests that the OFC is hypoactive in episodic migraine. STS with the Cefaly° device is able to normalize this hypoactivity. This indicates that STS exerts its beneficial effect via slow neuromodulatory mechanisms, as also previously shown for percutaneous occipital nerve stimulation in refractory cluster headache (Magis et al., BMC Neurology 2011). [less ▲]

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See detailEffects of transcranial magnetic stimulation coil orientation and pulse width on short-latency afferent inhibition
Hannah, Ricci; D'Ostilio, Kevin ULg; Goetz, Stefan et al

Poster (2015, March)

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See detailTMS can selectively activate and condition two different sets of excitatory synaptic inputs to corticospinal neurons in humans
Sommer, Martin; D'Ostilio, Kevin ULg; Cioccia, Matteo et al

Poster (2014, November)

Background: Current protocols or repetitive transcranial magnetic stimulation (rTMS) induce mixed facilitatory and inhibitory effects. More selective, quasi-monophasic high-frequency stimulators now ... [more ▼]

Background: Current protocols or repetitive transcranial magnetic stimulation (rTMS) induce mixed facilitatory and inhibitory effects. More selective, quasi-monophasic high-frequency stimulators now become available. We sought to investigate the impact of current direction and pulse width on intermittent theta burst stimulation (iTBS) effects on human motor cortex excitability. Also, we estimated strength-duration time constants from motor threshold and input-output (IO) curves for PA and AP orientations. Methods: We stimulated the dominant hand representation of the motor cortex in 15 healthy subjects, using “unidirectional biphasic” pulses generated by a controllable TMS machine (cTMS-3, Rogue Resolutions Ltd., Cardiff, UK), connected to a standard figure-8 coil. iTBS was applied conventionally, using 20 sequences of 2 seconds iTBS (10 bursts at 5 Hz burst repetition frequency, each burst consisting of 3 pulses of 80 % AMT intensity repeated at 50 Hz frequency). In separate sessions pulses differing in current direction and shape were applied: a) posterio-anterior (PA) current direction in the brain, 75 μs (iTBS_PA75). b) AP current direction, 45 μs (iTBS_AP45). Before and for 30 minutes after iTBS, we monitored the modulation of motor evoked potential (MEP) amplitude from the dominant first dorsal interosseus using conventional, monophasic, suprathreshold pulses generated by a Magstim 2002 stimulator, inducing PA currents in the brain, at 0.2 Hz frequency. In an additional study on ten healthy subjects, we investigated the effect the two coil orientations with three different pulse widths (30, 60 and 120 μs) on the IO curve and the latency of the motor evoked potentials (MEPs). Results: iTBS_AP45 yielded a pronounced and slightly delayed inhibition of MEP amplitude in all but one subjects, it was unrelated to the MEP latency differences. iTBS_PA75 had a variable and inconsistent effect that was in part related to the latency differenceAP-LM , in that long latency differences were correlated with the induction of inhibition rather than facilitation. We found a longer time constant for AP than PA orientation. MEP latencies yielded an interaction between pulse width and orientation, due mainly to longer onset latencies following AP stimuli of short duration. Conclusions: Current direction influences the outcome of iTBS, with a preference for AP currents. PA and AP stimuli activate the axons of neurones with different time constants. Those activated by AP pulses excite corticospinal outputs with a longer latency than those activated by PA pulses. AP pulses of short duration recruit long latency inputs most selectively. [less ▲]

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See detailControllable pulse parameter transcranial magnetic stimulator with enhanced circuit topology and pulse shaping
Peterchev, Angel; D'Ostilio, Kevin ULg; Rothwell, John et al

in Journal of Neural Engineering (2014), 11(5),

Abstract. Objective. This work aims at flexible and practical pulse parameter control in transcranial magnetic stimulation (TMS), which is currently very limited in commercial devices. Approach. We ... [more ▼]

Abstract. Objective. This work aims at flexible and practical pulse parameter control in transcranial magnetic stimulation (TMS), which is currently very limited in commercial devices. Approach. We present a third generation controllable pulse parameter device (cTMS3) that uses a novel circuit topology with two energy-storage capacitors. It incorporates several implementation and functionality advantages over conventional TMS devices and other devices with advanced pulse shape control. cTMS3 generates lower internal voltage differences and is implemented with transistors with lower voltage rating than prior cTMS devices. Main results. cTMS3 provides more flexible pulse shaping since the circuit topology allows four coil-voltage levels during a pulse, including approximately zero voltage. The nearzero coil voltage enables snubbing of the ringing at the end of the pulse without the need for a separate active snubber circuit. cTMS3 can generate powerful rapid pulse sequences (< 10 ms inter pulse interval) by increasing the width of each subsequent pulse and utilizing the large capacitor energy storage, allowing the implementation of paradigms such as paired-pulse and quadripulse TMS with a single pulse generation circuit. cTMS3 can also generate theta (50 Hz) burst stimulation with predominantly unidirectional electric field pulses. The cTMS3 device functionality and output strength are illustrated with electrical output measurements as well as a study of the effect of pulse width and polarity on the active motor threshold in 10 healthy volunteers. Significance. The cTMS3 features could extend the utility of TMS as a research, diagnostic, and therapeutic tool. [less ▲]

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See detailQuantitative multi-parameter mapping in parkinson’s disease: preliminary results
Rouillard, Maud ULg; D'Ostilio, Kevin ULg; Albinet, Cedric et al

Poster (2014, May)

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See detailBi-directional Modulation of Somatosensory Mismatch Negativity with Transcranial Direct Current Stimulation: An event Related Potential Study
Chen, Jui-Cheng; Hammerer, Dorothea; D'Ostilio, Kevin ULg et al

in The journal of Physiology (2014)

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See detailImpaired automatic and unconscious motor processes in Parkinson's disease
D'Ostilio, Kevin ULg; CREMERS, Julien ULg; DELVAUX, Valérie ULg et al

in Scientific Reports (2013)

While it is increasingly recognized that voluntary movements are produced by an interaction between conscious and unconscious processes, the role of the latter in Parkinson’s disease has received little ... [more ▼]

While it is increasingly recognized that voluntary movements are produced by an interaction between conscious and unconscious processes, the role of the latter in Parkinson’s disease has received little attention to date. Here, we administered a subliminal masked prime task to 15 Parkinson’s disease patients and 15 age-matched healthy elderly subjects. Compatibility effects were examined by manipulating the direction of the arrows and the interstimuli interval. Analysis of the positive compatibility effect revealed performance differences between the most and the least affected hand in Parkinson’s disease patients. Additionally, patients did not show the same tendency toward a negative compatibility effect as compared to elderly controls. These novel findings provide evidence supporting the role of basal ganglia circuits in controlling the balance between automatic motor response facilitation and inhibition. [less ▲]

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See detailExploration of the mechanisms underlying the ISPC effect: Evidence from behavioral and neuroimaging data
Grandjean, Julien; D'Ostilio, Kevin ULg; Fias, Wim et al

in Neuropsychologia (2013), 51

The item-specific proportion congruent (ISPC) effect in a Stroop task – the observation of reduced interference for color words mostly presented in an incongruent color – has attracted growing interest ... [more ▼]

The item-specific proportion congruent (ISPC) effect in a Stroop task – the observation of reduced interference for color words mostly presented in an incongruent color – has attracted growing interest since the original study by Jacoby (2003). Two mechanisms have been proposed to explain the effect: associative learning of contingencies and item-specific control through word reading modulation. Both interpretations have received empirical support from behavioral data. Therefore, the aim of this study was to investigate the responsible mechanisms of the ISPC effect with the classic two-item sets design using fMRI. Results showed that the ISPC effect is associated with increased activity in the anterior cingulate (ACC), dorsolateral prefrontal (DLPFC), and inferior and superior parietal cortex. Importantly, behavioral and fMRI analyses specifically addressing the respective contribution of associative learning and item-specific control mechanisms brought support for the contingency learning account of the ISPC effect. Results are discussed in reference to task and procedure characteristics that may influence the extent to which item-specific control and/or contingency learning contribute to the ISPC effect. [less ▲]

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See detailPreserved automatic inhibition effect after 1 Hz repetitive transcranial magnetic stimulation over the supplementary motor area
D'Ostilio, Kevin ULg; CREMERS, Julien ULg; DELVAUX, Valérie ULg et al

Poster (2013)

Background: It is widely accepted that medial frontal regions are involved in voluntary action control. Indeed, Sumner et al. (2007) have recently suggested that one of the mechanisms through which the ... [more ▼]

Background: It is widely accepted that medial frontal regions are involved in voluntary action control. Indeed, Sumner et al. (2007) have recently suggested that one of the mechanisms through which the supplementary motor area (SMA) contributes to voluntary control is automatic and unconscious motor inhibition. In this study, they administered a visuo-motor subliminal masked prime task (Eimer & Schlaghecken, 2003) to two patients with micro-lesions of the SMA and demonstrated an absence of automatic and unconscious inhibition as evoked by masked prime stimuli. This finding has been supported by neuroimaging data (D'Ostilio et al., 2012). Here, the aim of our research was to corroborate this result by means of a “virtual lesion” approach. Methods: For this purpose, we examined the effects of 1 Hz rTMS (train of 20 min; stimulus intensity 120 % of resting motor threshold) over the SMA of ten healthy volunteers, previously localized by functional magnetic resonance imaging (fMRI), on reaction time (RT) performance in the subliminal masked prime task. The functional localizer experiment consisted of four blocks of sequential finger tapping and 15 s of rest after each block. Imaging data were analyzed with SPM 8 and then were imported into the Brainsight software version 2.1.5. With such system, we were able to navigate across the subjects’ brain. The peak voxel in the SMA for each subject (at a statistical threshold of p < 0.05 uncorrected) was used as a target point for the rTMS session. Results: The mean motor threshold was 50.9 % of maximal stimulator output (SD: ± 4.86 %). Wilcoxon tests showed a significant effect of compatibility on RTs (sham: Z = 2.7, p = 0.007; rTMS: Z = 2.8, p = 0.005) and accuracy rate (sham: Z = 2.5, p = 0.01; rTMS: Z = 2.1, p = 0.03), subjects being slower and making more errors in compatible trials (sham: 391.64 ± 52 ms, 87.3 % of accuracy; rTMS: 396.66 ± 37 ms, 86.3 % of accuracy) in comparison to incompatible trials (sham: 357.45 ± 36 ms, 92.5 % of accuracy; rTMS: 356.25 ± 28 ms, 92.7 % of accuracy), suggesting motor inhibition. However, this NCE was preserved after rTMS over the SMA (RTs: Z = 0.87, p = 0.39; accuracy rate: Z = 0.71, p = 0.47). Conclusions: We conclude that long trains of low intensity 1 Hz rTMS did not affect the modulation of RT by subliminal stimuli, suggesting that the SMA might not be mandatory for the implementation of this automatic process. The limitation of this study is relative to the neural efficacy argument because we are not sure that TMS was strong enough to disturb the redundant organizational processing in the SMA or that other regions were not able to compensate for the virtually lesioned area. [less ▲]

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