Sebastiaan F W Neggers

University Medical Center Utrecht, Utrecht, Utrecht, Netherlands

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Publications (78)266.63 Total impact

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    ABSTRACT: Transcranial magnetic stimulation (TMS) is rapidly being adopted in neuroscience, medicine, psychology, and biology, for basic research purposes, diagnosis, and therapy. However, a coherent picture of how TMS affects neuronal processing, and especially how this in turn influences behavior, is still largely unavailable despite several studies that investigated aspects of the underlying neurophysiological effects of TMS. Perhaps as a result from this "black box approach," TMS studies show a large interindividual variability in applied paradigms and TMS treatment outcome can be quite variable, hampering its general efficacy and introduction into the clinic. A better insight into the biophysical, neuronal, and cognitive mechanisms underlying TMS is crucial in order to apply it effectively in the clinic and to increase our understanding of brain-behavior relationship. Therefore, computational and experimental efforts have been started recently to understand and control the effect TMS has on neuronal functioning. Especially, how the brain shapes magnetic fields induced by a TMS coil, how currents are generated locally in the cortical surface, and how they interact with complex functional neuronal circuits within and between brain areas are crucial to understand the observed behavioral changes and potential therapeutic effects resulting from TMS. Here, we review the current knowledge about the biophysical underpinnings of single-pulse TMS and argue how to move forward to fully understand and exploit the powerful technique that TMS can be.
    No preview · Article · Dec 2015 · Progress in brain research
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    ABSTRACT: Reward processing has been implicated in developmental disorders. However, the classic task to probe reward anticipation, the monetary incentive delay task, has an abstract coding of reward and no storyline and may therefore be less appropriate for use with developmental populations. We modified the task to create a version appropriate for use with children. We investigated whether this child-friendly version could elicit ventral striatal activation during reward anticipation in typically developing children and young adolescents (aged 9.5-14.5). In addition, we tested whether our performance-based measure of reward sensitivity was associated with anticipatory activity in ventral striatum. Reward anticipation was related to activity in bilateral ventral striatum. Moreover, we found an association between individual reward sensitivity and activity in ventral striatum. We conclude that this task assesses ventral striatal activity in a child-friendly paradigm. The combination with a performance-based measure of reward sensitivity potentially makes the task a powerful tool for developmental imaging studies of reward processing.
    Full-text · Article · Nov 2015 · PLoS ONE
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    ABSTRACT: Auditory verbal hallucinations (AVH) in schizophrenia are resistant to antipsychotic medication in approximately 25% of patients. Treatment with repetitive transcranial magnetic stimulation (rTMS) for refractory AVH has shown varying results. A stimulation protocol using continuous theta burst rTMS (TB-rTMS) showed high efficacy in open label studies. We tested TB-rTMS as a treatment strategy for refractory AVH in a double-blind, placebo-controlled trial. Seventy-one patients with AVH were randomly allocated to TB-rTMS or placebo treatment. They received 10 TB-rTMS or sham treatments over the left temporoparietal cortex in consecutive days. AVH severity was assessed at baseline, end of treatment and follow-up using the Psychotic Symptom Rating Scale (PSYRATS) and the Auditory Hallucinations Rating Scale (AHRS). Other schizophrenia-related symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). Seven patients dropped out before completing the study. In the remaining 64, AVH improved significantly after treatment in both groups as measured with both PSYRATS and AHRS. PANSS positive and general subscores also decreased, but the negative subscores did not. However, improvement did not differ significantly between the TB-rTMS and the placebo group on any outcome measure. Symptom reduction could be achieved in patients with medication-resistant hallucinations, even within 1 week time. However, as both groups showed similar improvement, effects were general (ie, placebo-effects) rather than specific to treatment with continuous TB-rTMS. Our findings highlight the importance of double-blind trials including a sham-control condition to assess efficacy of new treatments such as TMS. © The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.
    No preview · Article · Jul 2015 · Schizophrenia Bulletin
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    ABSTRACT: Corollary discharge (CD) refers to "copies" of motor signals sent to sensory areas, allowing prediction of future sensory states. They enable the putative mechanisms supporting the distinction between self- versus externally-generated sensations. Accordingly, many authors have suggested that disturbed CD engenders psychotic symptoms of schizophrenia, which are characterized by agency distortions. CD also supports perceived visual stability across saccadic eye movements and is used to predict the post-saccadic retinal coordinates of visual stimuli-a process called remapping. We tested whether schizophrenia patients (SZP) show remapping disturbances as evidenced by systematic transsaccadic mislocalizations of visual targets. SZP and healthy controls (HC) performed a task in which a saccadic target disappeared upon saccade initiation and-after a brief delay-reappeared at a horizontally-displaced position. HC judged the direction of this displacement accurately, despite spatial errors in saccade landing site, indicating that their comparison of the actual to predicted post-saccadic target location relied on accurate CD. SZP performed worse, and relied more on saccade landing site as a proxy for the pre-saccadic target, consistent with disturbed CD. This remapping failure was strongest in patients with more severe psychotic symptoms, consistent with the theoretical link between disturbed CD and phenomenological experiences in schizophrenia. Copyright © 2015, Journal of Neurophysiology.
    Full-text · Article · Jun 2015 · Journal of Neurophysiology
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    ABSTRACT: Lactate levels are measurable by MRS and are related to neural activity. Therefore, it is of interest to accurately measure lactate levels in the basal ganglia networks. If sufficiently stable, lactate measurements may be used to investigate alterations in dopaminergic signalling in the striatum, facilitating the detection and diagnosis of metabolic deficits. The aim of this study is to provide a J-difference editing MRS technique for the selective editing of lactate only, thus allowing the detection of lactate without contamination of overlapping macromolecules. As a validation procedure, macromolecule nulling was combined with J-difference editing, and this was compared with J-difference editing with a new highly selective editing pulse. The use of a high-field (7T) MR scanner enables the application of editing pulses with very narrow bandwidth, which are selective for lactate. We show that, despite the sensitivity to B0 offsets, the use of a highly selective editing pulse is more efficient for the detection of lactate than the combination of a broad-band editing pulse with macromolecule nulling. Although the signal-to-noise ratio of uncontaminated lactate detection in healthy subjects is relatively low, this article describes the test-retest performance of lactate detection in the striatum when using highly selective J-difference editing MRS at 7 T. The coefficient of variation, σw and intraclass correlation coefficients for within- and between-subject differences of lactate were determined. Lactate levels in the left and right striatum were determined twice in 10 healthy volunteers. Despite the fact that the test-retest performance of lactate detection is moderate with a coefficient of variation of about 20% for lactate, these values can be used for the design of new studies comparing, for example, patient populations with healthy controls. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    No preview · Article · Apr 2015 · NMR in Biomedicine
  • A.D. de Weijer · I.E.C. Sommer · S.F.W. Neggers

    No preview · Article · Mar 2015 · Brain Stimulation
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    Sebastiaan F W Neggers · Bram B Zandbelt · Michelle S Schall · Jeffrey D Schall
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    ABSTRACT: The primate cortico-basal ganglia circuits are understood to be segregated into parallel anatomically and functionally distinct loops. Anatomical and physiological studies in macaque monkeys are summarized as showing that an oculomotor loop begins with projections from the frontal eye fields (FEF) to the caudate nucleus, and a motor loop begins with projections from the primary motor cortex (M1) to the putamen. However, recent functional and structural neuroimaging studies of the human cortico-striatal system report evidence inconsistent with this organization. To obtain conclusive evidence, we directly compared the pattern of connectivity between cortical motor areas and the striatum in humans and macaques in vivo using probabilistic diffusion tractography. In macaques we found that FEF is connected with the head of the caudate and anterior putamen, and M1 is connected with more posterior sections of caudate and putamen, corroborating neuroanatomical tract tracing findings. However, in humans FEF and M1 are connected to largely overlapping portions of posterior putamen and only a small portion of the caudate. These results demonstrate that the cortico-basal connectivity for oculomotor and primary motor loop are not entirely segregated for primates at a macroscopic level, and that the description of the anatomical connectivity of cortico-striatal motor systems in humans does not parallel that of macaques, perhaps because of an expansion of prefrontal projections to striatum in humans. Copyright © 2014, Journal of Neurophysiology.
    Full-text · Article · Jan 2015 · Journal of Neurophysiology
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    ABSTRACT: The great majority of studies on repetitive transcranial magnetic stimulation (rTMS) as a therapeutic tool for auditory verbal hallucinations (AVH) have used 1-Hz stimulation with inconsistent results. Recently, it has been suggested that 20-Hz rTMS has strong therapeutic effects. It is conceivable that this 20-Hz stimulation is more effective than 1-Hz stimulation. The aim of this preliminary study is to investigate the efficacy of 20-Hz rTMS compared with 1-Hz rTMS as a treatment for AVH. Eighteen schizophrenia patients with medication-resistant AVH were randomized over two treatment groups. Each group received either 20 min of 1-Hz rTMS or 13 trains of 20-Hz rTMS daily over 1 week. After week 1, patients received a follow-up treatment once a week for 3 weeks. Stimulation location was based on individual AVH-related activation patterns identified with functional magnetic resonance imaging. Severity of AVH was monitored with the Auditory Hallucination Rating Scale (AHRS). Both groups showed a decrease in AVH after week 1 of rTMS. This decrease was significant for the 20-Hz group and the 1-Hz group. When the two treatment types were compared, no treatment type was superior. Based on these results we cannot conclude whether high frequency rTMS is more effective against AVH than is traditional 1-Hz rTMS. More research is needed to optimize stimulation parameters and to investigate potential target locations for stimulation.
    No preview · Article · Oct 2014 · Psychiatry Research: Neuroimaging
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    ABSTRACT: Stimulating brain areas with transcranial magnetic stimulation (TMS) while concurrently and noninvasively recording brain activity changes through functional MRI enables a new range of investigations about causal interregional interactions in the human brain. However, standard head-coil arrangements for current methods for concurrent TMS-functional MRI somewhat restrict the cortical brain regions that can be targeted with TMS because space in typical MR head coils is limited. Another limitation for concurrent TMS-functional MRI approaches concerns the estimation of the precise stimulation site, which can limit the interpretation of the activity changes induced by TMS and increase the variability of the stimulation effects. Here, we present a novel approach using flexible MR receiver coils, allowing for stimulation of a large part of the cortex including more lateral areas. Furthermore, we present a fast and economical method to determine the precise location of the stimulation coil during scanning. This point-based registration method can accurately compute, during scanning, where TMS pulses are delivered. We validated this approach by stimulating medial (M1) and more lateral (dorsal part of the supramarginal gyrus) brain areas concurrently with functional MRI. Activation close to but not directly at the stimulated location and in distal areas connected to the targeted site was observed. This study provides a proof of concept that TMS of medial and lateral brain areas is feasible without significantly compromising brain coverage and that one can precisely determine the exact coil location inside the bore to verify targeting of brain areas.
    No preview · Article · Oct 2014 · Journal of clinical neurophysiology: official publication of the American Electroencephalographic Society
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    ABSTRACT: Rapid and reactive control of movement is essential in a dynamic environment and is disrupted in several neuropsychiatric disorders. Nonhuman primate neurophysiology studies have made significant contributions to our understanding of how saccadic eye movements can be rapidly inhibited, changed, and monitored. These results highlight a frontostriatal network involved in gaze control and provide a strong basis for understanding how cognitive control of action is implemented in the human brain. The goal of the present study was to bridge human and nonhuman primate studies by investigating reactive control of eye movements during fMRI using a task that has been used in neurophysiology studies: the search-step task. This task requires a speeded response to a visual target (no-step trial). On a minority (40%) of trials, the target jumps to a new location and participants are instructed to inhibit the initially planned saccade and redirect gaze toward the new location (redirect trial). Compared with no-step trials, greater activation in a frontal oculomotor network, including frontal and supplementary eye fields (SEFs), and the striatum was observed during correctly executed redirect trials. Individual differences in stopping efficiency were related to striatal activation. Further, greater activation in SEF was in a region anterior to that activated during visually guided saccades and scaled positively with error magnitude, suggesting a prominent role in response monitoring. Combined, these data lend new evidence for a role of the striatum in reactive saccade control and further clarify the role of SEF in action inhibition and performance monitoring.
    Full-text · Article · Jun 2014 · The Journal of Neuroscience : The Official Journal of the Society for Neuroscience
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    Full-text · Dataset · Jun 2014
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    ABSTRACT: Imaging oculomotor subsystems in the cerebellum at 7 Tesla Melissa A Batson 1,2 , Natalia Petridou3, Dennis WJ Klomp3, Maarten A Frens1, Sebastian FW Neggers2 1Erasmus Medical Center, Rotterdam, Netherlands, 2Brain Center Rudolf Magnus, UMC Utrecht, Utrecht, Netherlands, 3Imaging Division, UMC Utrecht, Utrecht, Netherlands Introduction BOLD specificity and contrast to noise is enhanced at high fields allowing the delineation of neuronal activity in the human cortex at a finer scale than previously possible (1,2,4), and this is highly valuable when imaging anatomically complex structures with small nuclei and/or complex cytoarchitechtonics such as the cerebellum (Cb) (5). Common challenges, such as the physical location of the region of interest (ROI) and anatomical complexity, must be considered in order to reduce signal dropout particularly for Cb. This study was undertaken to prove efficacy of combinatorial methods which overcome these challenges while simultaneously leaving enough space within the transmit coil to investigate the involvement of Cb in oculomotor processes using eye tracking. Methods Four subjects were scanned at 7T (Philips) using two high-density 16-channel surface coils ((1), MR coils BV) and a volume transmit coil (Nova Medical, MA) with dual transmission for excitation. The coils were placed at the back of the head at the level of the Cb. B0 and B1 fields were shimmed separately on the Cb using in-house tools. fMRI data were acquired using a high-resolution segmented 3D-EPI (1.25mm3, 40 coronal slices covering Cb, volume acquisition time: ~3s). Anatomical data were also acquired: T1w MPRAGE (0.63 mm3), T2W TSE (0.28 x 0.28 x 2 mm). Subjects completed either a cued pro-/anti-saccade before a 2 Hz finger (thumb) movement task, or a saccade adaptation task (driven by unseen displacement of the saccade endpoint), each presented in a 20s on/off block design for 8 or 13 minutes, respectively. Eye movements were recorded via an infrared video-based eye tracking system (sampling rate 60 Hz; ViewPoint EyeTracker, Arrington Research, Scottsdale, USA), adapted for use at 7T by NordicNeuroLab (Bergen, Norway). FMRI images were realigned, coregistered with structural images and run through a GLM based on the block design. Contrast maps of activity versus rest, as well as for task-related learning over time for the adaptation task (contrasting baseline saccades with displaced saccades during an adaptation period), created with SPM8 were visualised with mricroN with a significance threshold of p < .05. Results Figure 1 shows that oculomotor areas of Cb, namely oculomotor vermis (VIc and VII), show large changes in signal during both eye movement tasks. Both CrusI and CrusII show signal changes when the task requires an eye movement that differs from the visual motor plan, and during saccade adaptation differences were observed in these areas only when contrasting activity from the start (and not the end) of adaptation with baseline. In addition, the location of activations for different types of movement is consistently separable in all subjects, i.e. for eye versus finger movements (Figure 2), and for different types of cognitive tasks, i.e. consciously reflexive versus volitional in pro/anti and unconsciously reflexive adaptation. Discussion BOLD signal changes in Cb resulting from motor activity in runs lasting less than ten minutes were strong enough to pinpoint activations very accurately within each individual. The setup used here leaves space within the transmit coil enabling eye tracking and benefiting investigations on the role of Cb in motor-learning and cognitive systems under both normal and adaptive situations. Oculomotor regions of Cb activate differently in the context of expected versus unexpected outcomes. For the eye movement tasks, BOLD signal changes were related to task difficulty with regard to outcome expectations of the motor system in response to visual inputs. This could relate to an activity-dependent representation of the presence or absence of a motor error within the regions already known to be associated with eye movements, linking to animal-based findings relating increased complex spikes from purkinje cells with motor learning (3). References (1) Shmuel et al, NeuroImage 35: 539–52, 2007. (2) Yacoub et al. NeuroImage 37: 1161–77, 2007 (3) Petridou et al, NMR Biomed 26(1): 65-73, 2013, (4) van der Zwaag et al, NeuroImage 67(C): 1–9, 2013, (5) Soetedio & Fuchs, J Neurosci 26(29): 7741-55, 2006.
    Full-text · Conference Paper · Jun 2014
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    ABSTRACT: Using an innovative combination of high-density multi-unit surface coils, dual transmission, ROI shimming and 3D parallel imaging at 7T it is possible to clearly image the deep and complex structures and functions of the cerebellum during various motor tasks, including oculomotor tasks requiring eye tracking. Results demonstrate superior functional localisation within both oculomotor vermis and, when a cognitive component is present, in both CrusI and CrusII. In addition, BOLD signal strengths vary with the magnitude of difficulty of the task for both motor and cognitive components in a manner consistent with the changes in firing patterns observed in animal cerebellum.
    Full-text · Conference Paper · May 2014
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    Full-text · Dataset · May 2014
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    ABSTRACT: Cognitive tasks that do not change the required response for a stimulus over time ('consistent mapping') show dramatically improved performance after relative short periods of practice. This improvement is associated with reduced brain activity in a large network of brain regions, including left prefrontal and parietal cortex. The present study used fMRI-guided repetitive transcranial magnetic stimulation (rTMS), which has been shown to reduce processing efficacy, to examine if the reduced activity in these regions also reflects reduced involvement, or possibly increased efficiency. First, subjects performed runs of a Sternberg task in the scanner with novel or practiced target-sets. This data was used to identify individual sites for left prefrontal and parietal peak brain activity, as well as to examine the change in activity related to practice. Outside of the scanner, real and sham rTMS was applied at left prefrontal and parietal cortex to examine their involvement novel and practiced conditions. Prefrontal as well as parietal rTMS significantly reduced target accuracy for novel targets. Prefrontal, but not parietal, rTMS interference was significantly lower for practiced than novel target-sets. rTMS did not affect non-target accuracy, or reaction time in any condition. These results show that task practice in a consistent environment reduces involvement of the prefrontal cortex. Our findings suggest that prefrontal cortex is predominantly involved in target maintenance and comparison, as rTMS interference was only detectable for targets. Findings support process switching hypotheses that propose that practice creates the possibility to select a response without the need to compare with target items. Our results also support the notion that practice allows for redistribution of limited maintenance resources.
    Full-text · Article · Dec 2013 · PLoS ONE
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    ABSTRACT: Background: Although some therapies may be beneficial for some patients in reducing tinnitus, there is no curative therapy. Repetitive transcranial magnetic stimulation (rTMS) has been applied as a treatment for chronic tinnitus, but the effect remains controversial. Material and methods: Fifty patients were treated with rTMS or placebo. Treatment consisted of 2,000 TMS pulses on each auditory cortex, at a rate of 1 Hz and an intensity of 110% of the individual motor threshold, on 5 consecutive days. rTMS and placebo effects were evaluated directly after treatment, after 1 week, and after 1, 3 and 6 months. Primary outcome was the Tinnitus Questionnaire (TQ). Secondary outcomes were the Tinnitus Handicap Inventory (THI) and a visual analogue scale. Results: At none of the follow-up evaluation moments a significant difference between rTMS and placebo was observed with respect to changes in TQ or THI scores relative to pretreatment scores. Multilevel modelling (MLM) analyses did not show a global treatment effect either. Patients with a higher degree of burden showed slightly greater improvement after rTMS (only significant on the THI with MLM analyses). Conclusion: Bilateral low-frequency rTMS of the auditory cortex was not effective in treating tinnitus.
    No preview · Article · Oct 2013 · Audiology and Neurotology
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    Bram B Zandbelt · Mirjam Bloemendaal · Sebastiaan F.W. Neggers · René S Kahn · Matthijs Vink
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    ABSTRACT: The ability to stop a prepared response (reactive inhibition) appears to depend on the degree to which stopping is expected (proactive inhibition). Functional MRI studies have shown that activation during proactive and reactive inhibition overlaps, suggesting that the whole neural network for reactive inhibition becomes already activated in anticipation of stopping. However, these studies measured proactive inhibition as the effect of stop-signal probability on activation during go trials. Therefore, activation could reflect expectation of a stop-signal (evoked by the stop-signal probability cue), but also violation of this expectation because stop-signals do not occur on go trials. We addressed this problem, using a stop-signal task in which the stop-signal probability cue and the go-signal were separated in time. Hence, we could separate activation during the cue, reflecting expectation of the stop-signal, from activation during the go-signal, reflecting expectation of the stop-signal or violation of that expectation. During the cue, the striatum, the supplementary motor complex (SMC), and the midbrain activated. During the go-signal, the right inferior parietal cortex (IPC) and the right inferior frontal cortex (IFC) activated. These findings suggest that the neural network previously associated with proactive inhibition can be subdivided into two components. One component, including the striatum, the SMC, and the midbrain, activated during the cue, implicating this network in proactive inhibition. Another component, consisting of the right IPC and the right IFC, activated during the go-signal. Rather than being involved in proactive inhibition, this network appears to be involved in processes associated with violation of expectations. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
    Full-text · Article · Sep 2013 · Human Brain Mapping
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    Tjerk Peter Gutteling · Soon Young Park · J Leon Kenemans · Sebastiaan F W Neggers
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    ABSTRACT: Perception of relevant visual object features can be modulated by the preparation of an action towards it ('action-modulated perception'). For instance, the perception of the orientation of a book can be enhanced when preparing to grasp it (but not when pointing to it). However, the underlying neuronal mechanisms are poorly understood. We argue that brain areas controlling arm movements are involved in establishing this effect through top-down feedback to early visual areas, similar to the neuronal mechanisms linking visual attention and eye movements. To investigate this involvement we applied transcranial magnetic stimulation (TMS) to a grasping motor area, the anterior intraparietal sulcus (aIPS), during grasping or pointing preparation. Concurrently, an orientation change detection task was performed. As a control area the vertex was stimulated. We found that stimulation of aIPS selectively modulates orientation sensitivity during action preparation, compared to control stimulation (vertex), negating the increased orientation sensitivity with grasping preparation over pointing preparation. We argue that aIPS is a critical part of the mechanism underlying perceptual modulations during action preparation. The present results and recent literature suggests that this action-modulated perception for hand movements is implemented through a cortical feedback connection between aIPS and early visual areas.
    Preview · Article · Apr 2013 · Journal of Neurophysiology
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    ABSTRACT: Our ability to regulate behavior based on past experience has thus far been examined using single movements. However, natural behavior typically involves a sequence of movements. Here, we examined the effect of previous trial type on the concurrent planning of sequential saccades using a unique paradigm. The task consisted of two trial types: no-shift trials, which implicitly encouraged the concurrent preparation of the second saccade in a subsequent trial; and target-shift trials, which implicitly discouraged the same in the next trial. Using the intersaccadic interval as an index of concurrent planning, we found evidence for context-based preparation of sequential saccades. We also used functional MRI-guided, single-pulse, transcranial magnetic stimulation on human subjects to test the role of the supplementary eye field (SEF) in the proactive control of sequential eye movements. Results showed that (i) stimulating the SEF in the previous trial disrupted the previous trial type-based preparation of the second saccade in the nonstimulated current trial, (ii) stimulating the SEF in the current trial rectified the disruptive effect caused by stimulation in the previous trial, and (iii) stimulating the SEF facilitated the preparation of second saccades based on previous trial type even when the previous trial was not stimulated. Taken together, we show how the human SEF is causally involved in proactive preparation of sequential saccades.
    Full-text · Article · Mar 2013 · Proceedings of the National Academy of Sciences
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    ABSTRACT: Previous studies investigated fMRI-guided repetitive Transcranial Magnetic Stimulation (rTMS) as an alternative treatment for auditory verbal hallucinations (AVH). This tailor-made treatment focuses at directing the rTMS coil to the location where hallucinatory activation is maximal, as identified with fMRI scans of individual patients. For the effective use of such treatment it is important to determine whether brain activation during AVH can be reliably detected using fMRI. Thirty-three psychotic patients indicated the presence of AVH during two subsequent scans. Reproducibility was measured by calculating 1) the distance between local maxima of significantly activated clusters and 2) percentage overlap of activation patterns over the two scans. These measurements were obtained both in single subjects and on group-level in five regions of interest (ROIs). ROIs consisted of the areas that were most frequently activated during AVH. Scans were considered reproducible if the distance between local maxima was smaller than 2cm, as rTMS-treatment may target an area of approximately 2-4cm. The median distance between local maxima was smaller than 2cm for all ROIs on single-subject level, as well as on group-level. In addition, on single-subject level median percentage overlap varied between 14 and 38% for the different ROIs. On group-level, this was substantially higher with percentages overlap varying between 34 and 98%. Based on these results, AVH-scans may be considered sufficiently reproducible to be suitable for fMRI-guided rTMS treatment.
    Full-text · Article · Feb 2013 · Schizophrenia Research

Publication Stats

2k Citations
266.63 Total Impact Points

Institutions

  • 2007-2015
    • University Medical Center Utrecht
      • Department of Psychiatry
      Utrecht, Utrecht, Netherlands
  • 2001-2011
    • Utrecht University
      • • Department of Psychiatry
      • • Division of Experimental Psychology
      Utrecht, Utrecht, Netherlands
  • 2002-2010
    • University of Groningen
      • Department of Psychiatry
      Groningen, Groningen, Netherlands
    • Netherlands Institute for Space Research, Utrecht
      Utrecht, Utrecht, Netherlands
  • 1999
    • Max Planck Society
      München, Bavaria, Germany