Alexander Münchau

YNICL Journal 2025 Journal Article

Differential resting-state functional connectivity patterns in functional movement disorders: Evidence for gait-disorder-specific aberrations

• Carl Alexander Gless
• Annemarie Reincke
• Anne Weissbach
• Christina Bolte
• Johanna Geritz
• Stephan Wolff
• Christof Degen-Plöger
• Oliver Granert

BACKGROUND: The clinical presentation of Functional Movement Disorders (FMD) is highly variable, encompassing gait disturbances and a wide range of hyper- and hypokinetic movement abnormalities. The neurobiological correlates distinguishing different phenotypes, particularly functional gait disorders, remain poorly understood. OBJECTIVE: To investigate whether functional gait disorders are associated with specific patterns of resting-state functional connectivity that distinguish them from other FMD phenotypes. METHODS: Thirty-eight FMD patients (9 with isolated gait disorders, 9 with combined gait and other motor symptoms, 20 with non-gait motor symptoms) and 20 healthy controls underwent resting-state functional MRI. Using seed-based connectivity analysis with eight bilateral regions of interest of the general, non FMD-specific motor network, we examined functional connectivity patterns across groups. RESULTS: Seed-based functional connectivity analysis revealed decreased connectivity between the left caudate nucleus and the left temporoparietal junction across gait disorder groups compared to both non-gait disorders and healthy controls. Patients with gait disorders showed decreased interhemispheric connectivity between primary sensorimotor areas compared to non-gait disorder patients, but partially increased connectivity compared to healthy controls. Both isolated and combined gait disorder groups demonstrated characteristic alterations in premotor-sensorimotor connectivity patterns, with distinct profiles between these subgroups. CONCLUSION: Our findings suggest distinct neurobiological signatures in functional gait disorders compared to other functional movement phenotypes. These findings might reflect specific pathophysiological mechanisms underlying functional gait disorders, particularly involving sensory feedback integration and motor control. These results provide new insights into the neurobiological basis of different FMD phenotypes and may contribute to the development of targeted therapeutic approaches.

YNICL Journal 2025 Journal Article

Evidence for temporal disintegration of information processing during sensorimotor integration in GTS

• Yifan Hao
• Paul Wendiggensen
• Annet Bluschke
• Tina Rawish
• Julia Friedrich
• Eszter Tóth-Fáber
• Zsanett Tárnok
• Veit Roessner

In Gilles de la Tourette syndrome (GTS), a neuropsychiatric disorder defined by the presence of tics, bindings of perceptual and motor processes in what cognitive theories refer to as event files is altered. The neural basis of such abnormal coupling though is currently unclear, particularly as regards oscillatory activity in theta, alpha, and beta frequency bands. The inter-relation between oscillatory activities in the theta, but also the alpha and beta band during event file binding and retrieval was investigated in the present study in patients with GTS and healthy controls (HC) using a well-established stimulus-response event file task and concomitant EEG recording. Behaviorally, binding effects did not differ between groups. Also, there were well-known patterns of theta, alpha and beta band activity during retrieval in both groups. In addition, corroborating previous findings in HC, in the period after event file binding and before retrieval, theta, alpha and beta band activity was found in the insula cortex, inferior/middle frontal and superior/middle temporal areas of the right hemisphere in both groups. However, in comparison to HC, GTS patients exhibited relatively less widespread oscillatory correlations between the post-binding and retrieval periods. Notably, a correlation between beta-band oscillations in the supplementary motor area (SMA) and oscillatory activity during the post-binding period was observed only in HC, but not in GTS. This absence in GTS may reflect a disrupted management of event files following retrieval. Overall, the findings suggest a relative decoupling of oscillatory activity associated with binding and retrieval processes in individuals with GTS.

YNIMG Journal 2024 Journal Article

EEG tensor decomposition delineates neurophysiological principles underlying conflict-modulated action restraint and action cancellation

• Negin Gholamipourbarogh
• Elena Eggert
• Alexander Münchau
• Christian Frings
• Christian Beste

Executive functions are essential for adaptive behavior. One executive function is the so-called 'interference control' or conflict monitoring another one is inhibitory control (i.e., action restraint and action cancelation). Recent evidence suggests an interplay of these processes, which is conceptually relevant given that newer conceptual frameworks imply that nominally different action/response control processes are explainable by a small set of cognitive and neurophysiological processes. The existence of such overarching neural principles has as yet not directly been examined. In the current study, we therefore use EEG tensor decomposition methods, to look into possible common neurophysiological signatures underlying conflict-modulated action restraint and action cancelation as mechanism underlying response inhibition. We show how conflicts differentially modulate action restraint and action cancelation processes and delineate common and distinct neural processes underlying this interplay. Concerning the spatial information modulations are similar in terms of an importance of processes reflected by parieto-occipital electrodes, suggesting that attentional selection processes play a role. Especially theta and alpha activity seem to play important roles. The data also show that tensor decomposition is sensitive to the manner of task implementation, thereby suggesting that switch probability/transitional probabilities should be taken into consideration when choosing tensor decomposition as analysis method. The study provides a blueprint of how to use tensor decomposition methods to delineate common and distinct neural mechanisms underlying action control functions using EEG data.

YNIMG Journal 2024 Journal Article

Neurophysiological principles underlying predictive coding during dynamic perception-action integration

• Roula Jamous
• Foroogh Ghorbani
• Moritz Mükschel
• Alexander Münchau
• Christian Frings
• Christian Beste

A major concept in cognitive neuroscience is that brains are "prediction machines". Yet, conceptual frameworks on how perception and action become integrated still lack the concept of predictability and it is unclear how neural processes may implement predictive coding during dynamic perception-action integration. We show that distinct neurophysiological mechanisms of nonlinearly directed connectivities in the theta and alpha band between cortical structures underlie these processes. During the integration of perception and motor codes, especially theta band activity in the insular cortex and temporo-hippocampal structures is modulated by the predictability of upcoming information. Here, the insular cortex seems to guide processes. Conversely, the retrieval of such integrated perception-action codes during actions heavily relies on alpha band activity. Here, directed top-down influence of alpha band activity from inferior frontal structures on insular and temporo-hippocampal structures is key. This suggests that these top-down effects reflect attentional shielding of retrieval processes operating in the same neuroanatomical structures previously involved in the integration of perceptual and motor codes. Through neurophysiology, the present study connects predictive coding mechanisms with frameworks specifying the dynamic integration of perception and action.

YNIMG Journal 2024 Journal Article

Neurophysiological processes reflecting the effects of the immediate past during the dynamic management of actions

• Tina Rawish
• Paul Wendiggensen
• Julia Friedrich
• Christian Frings
• Alexander Münchau
• Christian Beste

In recent years, there has been many efforts to establish a comprehensive theoretical framework explaining the working mechanisms involved in perception-action integration. This framework stresses the importance of the immediate past on mechanisms supporting perception-action integration. The present study investigates the neurophysiological principles of dynamic perception-action bindings, particularly considering the influence of the immediate history on action control mechanisms. For this purpose, we conducted an established stimulus-response binding paradigm during EEG recording. The SR-task measures stimulus-response binding in terms of accuracy and reaction time differences depending on the degree of feature overlap between conditions. Alpha, beta and theta band activity in distinct time domains as well as associated brain regions were investigated applying time-frequency analyses, a beamforming approach as well as correlation analyses. We demonstrate, for the first time, interdependencies of neuronal processes relying on the immediate past. The reconfiguration of an action seems to overwrite immediately preceding processes. The analyses revealed modulations of theta (TBA), alpha (ABA) and beta band activity (BBA) in connection with fronto-temporal structures supporting the theoretical assumptions of the considered conceptual framework. The close interplay of attentional modulation by gating irrelevant information (ABA) and binding and retrieval processes (TBA) is reflected by the correlation of ABA in all pre-probe-intervals with post-probe TBA. Likewise, the role of BBA in maintaining the event file until retrieval is corroborated by BBA preceding the TBA-associated retrieval of perception-action codes. Following action execution, TBA shifted towards visual association cortices probably reflecting preparation for upcoming information, while ABA and BBA continue to reflect processes of attentional control and information selection for goal-directed behavior. The present work provides the first empirical support for concepts about the neurophysiological mechanisms of dynamic management of perception and action.

YNICL Journal 2021 Journal Article

A neural noise account of Gilles de la Tourette syndrome

• Alexander Münchau
• Lorenza S. Colzato
• Azam AghajaniAfjedi
• Christian Beste

Tics, often preceded by premonitory urges, are the clinical hallmark of Tourette syndrome. They resemble spontaneous movements, but are exaggerated, repetitive and appear misplaced in a given communication context. Given that tics often go unnoticed, it has been suggested that they represent a surplus of action, or motor noise. In this conceptual position paper, we propose that tics and urges, but also patterns of the cognitive profile in Tourette syndrome might be explained by the principle of processing of neural noise and adaptation to it during information processing. We review evidence for this notion in the light of Tourette pathophysiology and outline why neurophysiological and imaging approaches are central to examine a possibly novel view on Tourette syndrome. We discuss how neurophysiological data at multiple levels of inspections, i.e., from local field potentials using intra-cranial recording to scalp-measured EEG data, in combination with imaging approaches, can be used to examine the neural noise account in Tourette syndrome. We outline what signal processing methods may be suitable for that. We argue that, as a starting point, the analysis of 1/f neural noise or scale-free activity may be suitable to investigate the role of neural noise and its adaptation during information processing in Tourette syndrome. We outline, how the neural noise perspective, if substantiated by further neurophysiological studies and re-analyses of existing data, may pave the way to novel interventions directly targeting neural noise levels and patterns in Tourette syndrome.

YNICL Journal 2021 Journal Article

Tourette syndrome as a motor disorder revisited – Evidence from action coding

• Emily Mielke
• Adam Takacs
• Maximilian Kleimaker
• Ronja Schappert
• Giulia Conte
• Rebecca Onken
• Till Künemund
• Julius Verrel

Because tics are the defining clinical feature of Tourette syndrome, it is conceptualized predominantly as a motor disorder. There is some evidence though suggesting that the neural basis of Tourette syndrome is related to perception-action processing and binding between perception and action. However, binding processes have not been examined in the motor domain in these patients. If it is particularly perception-action binding but not binding processes within the motor system, this would further corroborate that Tourette syndrome it is not predominantly, or solely, a motor disorder. Here, we studied N = 22 Tourette patients and N = 24 healthy controls using an established action coding paradigm derived from the Theory of Event Coding framework and concomitant EEG-recording addressing binding between a planned but postponed, and an interleaved immediate reaction with different levels of overlap of action elements. Behavioral performance during interleaved action coding was normal in Tourette syndrome. Response locked lateralized readiness potentials reflecting processes related to motor execution were larger in Tourette syndrome, but only in simple conditions. However, pre-motor processes including response preparation and configuration reflected by stimulus-locked lateralized readiness potentials were normal. This was supported by a Bayesian data analysis providing evidence for the null hypothesis. The finding that processes integrating different action-related elements prior to motor execution are normal in Tourette syndrome suggests that Tourette it is not solely a motor disorder. Considering other recent evidence, the data show that changes in "binding" in Tourette syndrome are specific for perception-action integration but not for action coding.

YNICL Journal 2020 Journal Article

Dopamine agonist treatment increases sensitivity to gamble outcomes in the hippocampus in de novo Parkinson’s disease

• Joyce P.M. van der Vegt
• Oliver J. Hulme
• Kristoffer H. Madsen
• Carsten Buhmann
• Bastiaan R. Bloem
• Alexander Münchau
• Rick C. Helmich
• Hartwig R. Siebner

BACKGROUND: Parkinson's disease is associated with severe nigro-striatal dopamine depletion, leading to motor dysfunction and altered reward processing. We previously showed that drug-naïve patients with Parkinson's disease had a consistent attenuation of reward signalling in the mesolimbic and mesocortical system. Here, we address the neurobiological effects of dopaminergic therapy on reward sensitivity in the mesolimbic circuitry, and how this may contribute to neuropsychiatric symptoms. OBJECTIVES: We tested the hypothesis that (1) dopaminergic treatment would restore the attenuated, mesolimbic and mesocortical responses to reward; and (2) restoration of reward responsivity by dopaminergic treatment would predict motor performance and the emergence of impulse control symptoms. METHODS: In 11 drug-naïve Parkinson patients, we prospectively assessed treatment-induced changes in reward processing before, and eight weeks after initiation of monotherapy with dopamine agonists. They were compared to 10 non-medicated healthy controls who were also measured longitudinally. We used whole-brain functional magnetic resonance imaging at 3 Tesla to assess the reward responsivity of the brain to monetary gains and losses, while participants performed a simple consequential gambling task. RESULTS: In patients, dopaminergic treatment improved clinical motor symptoms without significantly changing task performance. Dopamine agonist therapy induced a stronger reward responsivity in the right hippocampus with higher doses being less effective. None of the patients developed impulse control disorders in the follow-up period of four years. CONCLUSIONS: Short-term treatment with first-ever dopaminergic medication partially restores deficient reward-related processing in the hippocampus in de novo Parkinson's disease.

YNICL Journal 2019 Journal Article

Predictive coding and adaptive behavior in patients with genetically determined cerebellar ataxia––A neurophysiology study

• Sinem Tunc
• Nastasja Baginski
• Juliane Lubs
• Julien F. Bally
• Anne Weissbach
• Magdalena Khira Baaske
• Vera Tadic
• Norbert Brüggemann

Genetically determined cerebellar ataxias (CA) are a heterogeneous group of disorders with progressive decline of cerebellar functions. The cerebellum influences internal forward models that play a role in cognitive control, but whether these processes are dysfunctional in CA is unclear. Here, we examined sensory predictive coding processes and response adaptation in CA and healthy controls (HC) using behavioral tests with concomitant EEG recordings. N = 23 patients and N = 29 age- and sex-matched HC were studied. Sensory prediction coding was tested with an auditory distraction paradigm and error-related behavioral adaptation with a visual flanker task. As neurophysiological markers we studied different event-related potentials: the P3a for orientation of attention; the N2 and the error-related negativity (ERN) for cognitive adaptation processes/consequences of response errors; error-related positivity (Pe) for error-awareness; the mismatch negativity (MMN) for sensory predictive coding; and reorientation negativity (RON) for reorientation after unexpected events. Overall reaction times were slower in patients compared to HC, but error rates did not differ. Both in patients and HC, P3a amplitudes were larger in distraction trials, but the P3a amplitude was smaller in patients compared to HC. The MMN as well as behavioral and EEG-correlates of response adaptation (ERN/N2) did not differ between groups, while the Pe was attenuated in patients. During sensory predictive coding, RON amplitudes were significantly larger in HC compared to patients. In HC, but not in patients, RON amplitudes were also larger in deviant compared to frequent trials. Processes generating internal forward models are largely intact in genetically determined CA, whereas updating of mental models and error awareness are disturbed in these patients.

YNIMG Journal 2016 Journal Article

A systems neurophysiology approach to voluntary event coding

• Vanessa A. Petruo
• Ann-Kathrin Stock
• Alexander Münchau
• Christian Beste

Mechanisms responsible for the integration of perceptual events and appropriate actions (sensorimotor processes) have been subject to intense research. Different theoretical frameworks have been put forward with the “Theory of Event Coding (TEC)” being one of the most influential. In the current study, we focus on the concept of ‘event files’ within TEC and examine what sub-processes being dissociable by means of cognitive-neurophysiological methods are involved in voluntary event coding. This was combined with EEG source localization. We also introduce reward manipulations to delineate the neurophysiological sub-processes most relevant for performance variations during event coding. The results show that processes involved in voluntary event coding included predominantly stimulus categorization, feature unbinding and response selection, which were reflected by distinct neurophysiological processes (the P1, N2 and P3 ERPs). On a system's neurophysiological level, voluntary event-file coding is thus related to widely distributed parietal-medial frontal networks. Attentional selection processes (N1 ERP) turned out to be less important. Reward modulated stimulus categorization in parietal regions likely reflecting aspects of perceptual decision making but not in other processes. The perceptual categorization stage appears central for voluntary event-file coding.

YNICL Journal 2014 Journal Article

Altered intrahemispheric structural connectivity in Gilles de la Tourette syndrome

• Bastian Cheng
• Hanna Braass
• Christos Ganos
• Andras Treszl
• Katja Biermann-Ruben
• Friedhelm C. Hummel
• Kirsten Müller-Vahl
• Alfons Schnitzler

Gilles de la Tourette syndrome (GTS) is a common developmental neuropsychiatric disorder characterized by tics and frequent psychiatric comorbidities, often causing significant disability. Tic generation has been linked to disturbed networks of brain areas involved in planning, controlling and execution of actions, particularly structural and functional disorders in the striatum and cortico-striato-thalamo-cortical loops. We therefore applied structural diffusion tensor imaging (DTI) to characterize changes in intrahemispheric white matter connectivity in cortico-subcortical circuits engaged in motor control in 15 GTS patients without psychiatric comorbidities. White matter connectivity was analyzed by probabilistic fiber tractography between 12 predefined cortical and subcortical regions of interest. Connectivity values were combined with measures of clinical severity rated by the Yale Global Tic Severity Scale (YGTSS). GTS patients showed widespread structural connectivity deficits. Lower connectivity values were found specifically in tracts connecting the supplementary motor areas (SMA) with basal ganglia (pre-SMA-putamen, SMA-putamen) and in frontal cortico-cortical circuits. There was an overall trend towards negative correlations between structural connectivity in these tracts and YGTSS scores. Structural connectivity of frontal brain networks involved in planning, controlling and executing actions is reduced in adult GTS patients which is associated with tic severity. These findings are in line with the concept of GTS as a neurodevelopmental disorder of brain immaturity.

YNIMG Journal 2012 Journal Article

A novel dual-site transcranial magnetic stimulation paradigm to probe fast facilitatory inputs from ipsilateral dorsal premotor cortex to primary motor cortex

• Sergiu Groppa
• Nicole Werner-Petroll
• Alexander Münchau
• Günther Deuschl
• Matthew F.S. Ruschworth
• Hartwig R. Siebner

The dorsal premotor cortex (PMd) plays an import role in action control, sensorimotor integration and motor recovery. Animal studies and human data have demonstrated direct connections between ipsilateral PMd and primary motor cortex hand area (M1HAND). In this study we adopted a multimodal approach combining highly focal dual-site TMS (dsTMS) and diffusion tensor imaging (DTI) to probe ipsilateral effective and structural connectivity between PMd and M1HAND in humans. A suprathreshold test stimulus (TS) was applied to left M1HAND producing a motor evoked potential (MEP) and a subsequent conditioning stimulus (CS) to ipsilateral rostromedial PMd at short latencies ranging from of 0. 8 to 2. 0ms. At an interstimulus interval of 1. 2ms, dsTMS of the left M1HAND and PMd facilitated MEP amplitudes relative to unconditioned TMS of M1HAND. This PMd to M1HAND facilitation was absent during voluntary contraction of the target muscle. During a two-choice reaction time task, PMd–M1HAND facilitation was only observed when dsTMS was given 125ms after presentation of the cue and subjects responded with their right hand, but not for left hand responses. Our results reveal a short-latency PMd to M1HAND connection which modulates excitability of ipsilateral M1HAND in a task and effector specific manner. DTI revealed that individual increases in PMd to M1HAND facilitation were correlated with fractional anisotropy and axial diffusivity in the juxtacortical white matter underlying the caudal portion of the left superior frontal gyrus. This finding shows that the functional strength of this connection from medial PMd to M1HAND has a microstructural correlate in the underlying subcortical white matter. This novel dsTMS paradigm can be used to non-invasively probe effective PMd to M1HAND connectivity in healthy individuals and patients with impaired hand function.

YNIMG Journal 2012 Journal Article

Increased sensory feedback in Tourette syndrome

• Katja Biermann-Ruben
• Anastasia Miller
• Stephanie Franzkowiak
• Jennifer Finis
• Bettina Pollok
• Claudia Wach
• Martin Südmeyer
• Melanie Jonas

Tourette syndrome (TS) is a neuro-psychiatric disorder being characterized by motor and phonic tics typically preceded by sensory urges. Given the latter the role of the sensory system and sensorimotor interaction in TS has recently gained increased attention. 12 TS patients and 12 matched control subjects performed two tasks, requiring simple finger movements: a Go/NoGo task and a self paced movement task. Neurophysiological data was recorded using magnetoencephalography (MEG). Event related responses around movement onset, i. e. motor field (MF) occurring directly prior to the movement and movement evoked field (MEF) immediately after movement onset were analyzed using dipole modeling. MF peak amplitudes did not differ between groups in either task. In contrast, in both tasks MEF peak amplitudes were increased in TS patients. Moreover, larger MEF amplitudes during self paced movements were inversely correlated with motor tic frequency and severity. Enlarged MEF amplitudes as a marker of early sensory feedback of one's own movements probably represent enlarged sensory input from the periphery resulting from altered subcortical gating. We conclude that TS patients exhibit altered sensory–motor processing involved in voluntary movement control, which might also be successful in tic control.

YNIMG Journal 2008 Journal Article

The cortical motor threshold reflects microstructural properties of cerebral white matter

• Stefan Klöppel
• Tobias Bäumer
• Johan Kroeger
• Martin A. Koch
• Christian Büchel
• Alexander Münchau
• Hartwig R. Siebner

Transcranial magnetic stimulation (TMS) can be used to probe distinct aspects of excitability of the primary motor hand area (M1Hand). The motor threshold (MT) reflects the trans-synaptic excitability of corticospinal output neurons. The MT corresponds to the minimal intensity at which TMS evokes a contralateral motor response. Here, we employed diffusion-weighted imaging (DWI) to examine whether inter-individual differences in MT of the left and right M1Hand, an index of cortical excitability, are associated with variations in fractional anisotropy (FA), an index of white matter microstructure. Resting and active MT showed an inverse linear relationship with regional FA values in large bihemispheric clusters, including the white matter underlying primary motor, premotor and posterior prefrontal cortices, as well as the genu of the internal capsule, cerebral peduncles and corpus callosum. The linear increase in FA with cortical excitability as indexed by the MT remained significant after controlling for differences in handedness or coil–cortex distance. The posterior limb of the internal capsule, where fast-conducting corticospinal fibres from M1Hand pass through, showed only a weak linear relationship between FA and MT. The FA measurements show that a high level of corticospinal excitability is associated with a higher fibre coherence in large parts of cerebral white matter. The higher FA values in the white matter beneath premotor and motor cortices may reflect a structural property of cortico-cortical connections that renders M1Hand more susceptible to TMS-induced trans-synaptic excitation of the corticospinal fibres and may account for the inverse linear relationship between MT and FA.

YNIMG Journal 2007 Journal Article

The effect of handedness on cortical motor activation during simple bilateral movements

• Stefan Klöppel
• Thilo van Eimeren
• Volkmar Glauche
• Anna Vongerichten
• Alexander Münchau
• Richard S.J. Frackowiak
• Christian Büchel
• Cornelius Weiller

The neuronal correlates of handedness are still poorly understood. Here we used event-related functional magnetic resonance imaging to investigate the impact of handedness on neuronal activation of the primary sensorimotor cortex, supplementary motor area and dorsal premotor cortex during simple unilateral and bilateral finger movements. In 16 right-handed and 16 left-handed individuals, we mapped changes in regional neuronal activity while participants responded to four symbolic cues presented in a pseudorandom order. According to pre-specified cues, they pressed a button with their right, left or both index fingers or withheld a response. For unilateral right index finger button presses, reaction times, motor and premotor activity were the same for both right- and left-handers. Compared with right-handers, left-handers had shorter reaction times with unilateral left index finger button presses, along with greater activation of the supplementary motor area and right frontal opercular cortex. Simultaneous bilateral compared with unilateral button presses led to a relative increase of activity in the right and left dorsal premotor cortex and the right primary sensorimotor cortex in right but not left-handers. Neither right nor left-handers showed any tendency during bilateral button presses towards faster responses with the dominant hand and the reaction times were equal in the two groups. Therefore, we conclude that the relative increase of activity in dorsal premotor and right primary sensorimotor cortices in right-handers represents a genuine difference in bimanual motor control related to handedness.

YNIMG Journal 2006 Journal Article

Implementation of visuospatial cues in response selection

• Thilo van Eimeren
• Thomas Wolbers
• Alexander Münchau
• Christian Büchel
• Cornelius Weiller
• Hartwig Roman Siebner

We used functional magnetic resonance imaging to examine neuronal activity reflecting the dynamic interplay of external and internal guidance of action. Participants performed a choice reaction time task based on spatial visual cues with their right and left middle and index finger. In a given trial, the cue either fully determined the motor response (no-selection) or indicated the number and location of alternative responses (selection). Compared with fully determined responses, the selection among (two to four) alternative responses activated a widespread bilateral parieto-premotor-prefrontal cortical network along with the cerebellum. Within this network, task-related activity patterns allowed to delineate two sets of brain areas. In the anterior part of rostral dorsal premotor cortex (PMd), the rostral cingulate and supplementary motor area and the right dorsolateral prefrontal cortex, the increase in activity was independent of spatially defined restrictions. In contrast, there was an additional increase in activity in the posterior part of rostral PMd, superior parietal lobule and parieto-occipital sulcus bilaterally as well as in the right anterior intraparietal sulcus, when the visuospatial cue imposed specific constraints on response selection. We propose that the latter set of dorsal parieto-frontal areas subserves rapid implementation of spatial information during visually guided response selection.

YNIMG Journal 2006 Journal Article

Investigating the human mirror neuron system by means of cortical synchronization during the imitation of biological movements

• Klaus Kessler
• Katja Biermann-Ruben
• Melanie Jonas
• Hartwig Roman Siebner
• Tobias Bäumer
• Alexander Münchau
• Alfons Schnitzler

The human mirror neuron system (MNS) has recently been a major topic of research in cognitive neuroscience. As a very basic reflection of the MNS, human observers are faster at imitating a biological as compared with a non-biological movement. However, it is unclear which cortical areas and their interactions (synchronization) are responsible for this behavioural advantage. We investigated the time course of long-range synchronization within cortical networks during an imitation task in 10 healthy participants by means of whole-head magnetoencephalography (MEG). Extending previous work, we conclude that left ventrolateral premotor, bilateral temporal and parietal areas mediate the observed behavioural advantage of biological movements in close interaction with the basal ganglia and other motor areas (cerebellum, sensorimotor cortex). Besides left ventrolateral premotor cortex, we identified the right temporal pole and the posterior parietal cortex as important junctions for the integration of information from different sources in imitation tasks that are controlled for movement (biological vs. non-biological) and that involve a certain amount of spatial orienting of attention. Finally, we also found the basal ganglia to participate at an early stage in the processing of biological movement, possibly by selecting suitable motor programs that match the stimulus.

YNIMG Journal 2003 Journal Article

Repeated premotor rTMS leads to cumulative plastic changes of motor cortex excitability in humans

• Tobias Bäumer
• Rüdiger Lange
• Joachim Liepert
• Cornelius Weiller
• Hartwig R Siebner
• John C Rothwell
• Alexander Münchau

We explored the aftereffects of two premotor 1 Hz rTMS sessions on motor cortex excitability in healthy humans. In experiment 1, 11 healthy right-handed volunteers received 20-min submotor threshold 1 Hz rTMS trains over the left premotor cortex on 2 consecutive days. Left motor cortex excitability was determined at baseline, immediately after, 30, 60, 120 min, and 24 h after each rTMS session. We measured motor thresholds, amplitudes of motor-evoked potentials, silent periods, and paired-pulse excitability at interstimulus intervals (ISI) of 3–7, 10, and 15 ms. In experiment 2, 5 volunteers received two identical rTMS trains on Days 1 and 7. Measurements were carried out on Day 1 (first rTMS train), Day 2, and Day 7 (second rTMS train). In experiment 1 there was a selective increase of paired pulse facilitation at an ISI of 7 ms after rTMS lasting for less than 30 min on Day 1. This effect was also present after rTMS on Day 2. However, it persisted for at least 2 h. In experiment 2 the same extra facilitation was induced by rTMS on Days 1 and 7 but not on Day 2. It lasted for less than 30 min on both Day 1 and Day 7. We conclude that 1 Hz premotor rTMS leads to cumulative plastic changes of intrinsic motor cortex excitability when repeated within 24 h but not after 1 week, implying the formation of memory after the first rTMS train lasting more than a day but less than a week.

YNIMG Journal 2001 Journal Article

Effects of motor and premotor cortex repetitive transcranial magnetic stimulation (rTMS) on reaction times in a masked priming task

• Friederike Schlaghecken
• Alexander Münchau
• Bastiaan Bloem
• John C. Rothwell
• Martin Eimer

YNIMG Journal 2001 Journal Article

Low-frequency submotor threshold repetitive transcranial

• Alexander Münchau
• Bastlaan B. Bloem
• Kerstin Irlbacher
• Michael R. Trimble
• John C. Rothwell