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IS 40. Visual exploration
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Society Proceedings / Clinical Neurophysiology 124 (2013) e39–e187
IS 40. Visual exploration—R.M. Müri (Neurologische Universitätsklinik, Abteilung für Neuropsychologische, Bern, Switzerland) Traditionally, attention is seen as the preferential processing of objects in detriment of others. Attentional selection of an object of the visual space can be made in two different ways: Overt attention is the term used to describe attending by means of looking, and covert attention is used to describe attending without looking. Thus, visual exploration reflects the complex interaction between eye movements, visual attention and visual processing. The network involved in visual attention is well known, and parietal and frontal regions involved in attentional control are also involved in eye movement control. Visual exploration may by disturbed by attentional deficits such as hemineglect, or by visual field defects. The analysis of the visual exploration is useful to study mechanisms of attention and its disorders. Non-invasive brain stimulation (NIBS) may be used to interfere specifically with the attentional network. In healthy subjects, we are able to induce neglect-like visual exploration by the stimulation of the posterior parietal cortex. In patients with neglect, NIBS of the contralesional hemisphere is able to influence visual exploration by interfering with interhemispheric balance. The aim of the presentation is to overview the effect of NIBS on visual exploration in both healthy subjects and patients with visual hemineglect.
provided by EMCS be also produced by non-invasive rTMS? (ii) Could a therapeutic application of rTMS be conceivable in patients with chronic pain? (iii) Were these effects predictive for the outcome of EMCS? (iv) Could rTMS help in understanding the mechanisms of action of EMCS? We performed various experiments based on the assessment of rTMS-induced pain relief with respect to: stimulus frequency; stimulation site; time course of the effects; influence of sensory deficit within the painful zone; combination with acute provoked pain. The assessment included clinical scoring of pain level; quantified sensory testing; cortical excitability studies. We found that pain can be transiently relieved in patients with chronic neuropathic pain by applying rTMS at 10–20 Hz over the motor cortex corresponding to the painful zone. The targeting within the precentral gyrus influenced the results, justifying the use of an image-guided navigated approach. Pain relief was associated with changes in sensory discrimination within the painful zone and with the restoration of intracortical inhibitory processes. Cortical stimulation over motor areas is able to produce analgesic effects. Regarding rTMS, the parameters of stimulation and the way of managing rTMS therapy remained to be optimized before considering this technique as a therapeutic tool. Conversely, motor cortex rTMS could be used to select good candidates for the surgical implantation of a cortical stimulator. doi:10.1016/j.clinph.2013.04.061
doi:10.1016/j.clinph.2013.04.059
Invited Speaker IS 41. Attention, brain oscillations and frequency-tuned TMS—G. Thut (University of Glasgow, Department of Psychology, Glasgow, United Kingdom) Brain oscillations reflect interactions between neuronal elements which functionally assemble through synchronization in specific frequency bands, depending on the state of the brain and on the task that is currently being executed. This gives rise to brain rhythms that can be measured on the scalp by electroencephalography (EEG). Transcranial magnetic stimulation (TMS) can be used to stimulate cortical areas in rhythmic pulse-trains, at frequencies that characterize EEG-signals. This raises two intriguing questions: Could frequency-tuned TMS be used to transiently entrain brain oscillations, and would this result in behavioural consequences? My talk covers (1) EEG-signatures that carry information on the excitability of visual cortex (amenable to attention control) and predict perception of an upcoming visual event. It then addresses the questions whether (2) these signatures can be transiently entrained by frequency-tuned rhythmic TMS, and whether (3) this alters perception in expected directions, i.e. in line with the proposed functional roles of these oscillations in perception and attention. doi:10.1016/j.clinph.2013.04.060
IS 42. Brain stimulation in pain treatment—J.-P. Lefaucheur, S.S. Ayache, W.H. Farhat, C. Goujon (Hôpital Henri Mondor, Université Paris-Est-Créteil, Service de Physiologie–Explorations Fonctionnelles, EA 4391, Créteil, France) Chronic epidural motor cortex stimulation (EMCS) induces significant pain relief in patients suffering from chronic neuropathic pain. Repetitive transcranial magnetic stimulation (rTMS) allowed several questions to be addressed: (i) could the analgesic effects
IS 43. tDCS-from resting state network modulation to enhancing psychotherapy—F. Padberg a,b, T. Rüther b, U. Palm b, A. Hasan b, A. Linhardt b, B. Ertl-Wagner c, D. Keeser b,c (a Ludwig-MaximiliansUniversität München, Klinik für Psychiatrie und Psychotherapie, München, Germany, b Ludwig-Maximilian University Munich, Department of Psychiatry and Psychotherapy, Munich, Germany, c Ludwig-Maximilian University Munich, Department for Clinical Radiology, Munich, Germany) Introduction: Anodal tDCS of the dorsolateral prefrontal cortex (DLPFC) has been associated with improvement of cognitive performance and suggested as therapeutic intervention for several neurological and psychiatric disorders. Most recently, anodal tDCS has been shown to improve deficient cognitive control in major depression. Based on previous behavioral findings and preclinical data of tDCS inducing long-term NMDA receptor and/or BDNF-dependent plasticity, anodal tDCS of the DLPFC may be theoretically suitable for enhancing the effects of psychotherapeutic interventions similar to pharmacological strategies like d-cycloserine. Objectives: To investigate whether anodal tDCS of the DLPFC applied as group intervention enhances the effect of a behavioral group therapy program for nicotine dependency. Material and methods: Following the investigation of tDCS mediated effects in resting state EEG activity and event related potentials, these effects were further characterized using resting state fMRI in healthy subjects who underwent real and sham tDCS in a randomized cross-over design. tDCS was applied for 20 min at 2 mA with the anode positioned over the left DLPFC and the cathode over the right supra-orbital region. Resting state brain activity was measured before and after tDCS with 3T fMRI. Subsequently, the same tDCS protocol was used in subjects who underwent a behavioral psychotherapy group program for nicotine dependency. tDCS is applied in a placebo-controlled, double-blind pilot study in 36 subjects who want to quit smoking. This study is still ongoing (ClinicalTrials.gov: NCT01729507). Results: In healthy subjects, significant changes of regional brain activity were found for the default mode network (DMN) and both
Society Proceedings / Clinical Neurophysiology 124 (2013) e39–e187
IS 40. Visual exploration—R.M. Müri (Neurologische Universitätsklinik, Abteilung für Neuropsychologische, Bern, Switzerland) Traditionally, attention is seen as the preferential processing of objects in detriment of others. Attentional selection of an object of the visual space can be made in two different ways: Overt attention is the term used to describe attending by means of looking, and covert attention is used to describe attending without looking. Thus, visual exploration reflects the complex interaction between eye movements, visual attention and visual processing. The network involved in visual attention is well known, and parietal and frontal regions involved in attentional control are also involved in eye movement control. Visual exploration may by disturbed by attentional deficits such as hemineglect, or by visual field defects. The analysis of the visual exploration is useful to study mechanisms of attention and its disorders. Non-invasive brain stimulation (NIBS) may be used to interfere specifically with the attentional network. In healthy subjects, we are able to induce neglect-like visual exploration by the stimulation of the posterior parietal cortex. In patients with neglect, NIBS of the contralesional hemisphere is able to influence visual exploration by interfering with interhemispheric balance. The aim of the presentation is to overview the effect of NIBS on visual exploration in both healthy subjects and patients with visual hemineglect.
provided by EMCS be also produced by non-invasive rTMS? (ii) Could a therapeutic application of rTMS be conceivable in patients with chronic pain? (iii) Were these effects predictive for the outcome of EMCS? (iv) Could rTMS help in understanding the mechanisms of action of EMCS? We performed various experiments based on the assessment of rTMS-induced pain relief with respect to: stimulus frequency; stimulation site; time course of the effects; influence of sensory deficit within the painful zone; combination with acute provoked pain. The assessment included clinical scoring of pain level; quantified sensory testing; cortical excitability studies. We found that pain can be transiently relieved in patients with chronic neuropathic pain by applying rTMS at 10–20 Hz over the motor cortex corresponding to the painful zone. The targeting within the precentral gyrus influenced the results, justifying the use of an image-guided navigated approach. Pain relief was associated with changes in sensory discrimination within the painful zone and with the restoration of intracortical inhibitory processes. Cortical stimulation over motor areas is able to produce analgesic effects. Regarding rTMS, the parameters of stimulation and the way of managing rTMS therapy remained to be optimized before considering this technique as a therapeutic tool. Conversely, motor cortex rTMS could be used to select good candidates for the surgical implantation of a cortical stimulator. doi:10.1016/j.clinph.2013.04.061
doi:10.1016/j.clinph.2013.04.059
Invited Speaker IS 41. Attention, brain oscillations and frequency-tuned TMS—G. Thut (University of Glasgow, Department of Psychology, Glasgow, United Kingdom) Brain oscillations reflect interactions between neuronal elements which functionally assemble through synchronization in specific frequency bands, depending on the state of the brain and on the task that is currently being executed. This gives rise to brain rhythms that can be measured on the scalp by electroencephalography (EEG). Transcranial magnetic stimulation (TMS) can be used to stimulate cortical areas in rhythmic pulse-trains, at frequencies that characterize EEG-signals. This raises two intriguing questions: Could frequency-tuned TMS be used to transiently entrain brain oscillations, and would this result in behavioural consequences? My talk covers (1) EEG-signatures that carry information on the excitability of visual cortex (amenable to attention control) and predict perception of an upcoming visual event. It then addresses the questions whether (2) these signatures can be transiently entrained by frequency-tuned rhythmic TMS, and whether (3) this alters perception in expected directions, i.e. in line with the proposed functional roles of these oscillations in perception and attention. doi:10.1016/j.clinph.2013.04.060
IS 42. Brain stimulation in pain treatment—J.-P. Lefaucheur, S.S. Ayache, W.H. Farhat, C. Goujon (Hôpital Henri Mondor, Université Paris-Est-Créteil, Service de Physiologie–Explorations Fonctionnelles, EA 4391, Créteil, France) Chronic epidural motor cortex stimulation (EMCS) induces significant pain relief in patients suffering from chronic neuropathic pain. Repetitive transcranial magnetic stimulation (rTMS) allowed several questions to be addressed: (i) could the analgesic effects
IS 43. tDCS-from resting state network modulation to enhancing psychotherapy—F. Padberg a,b, T. Rüther b, U. Palm b, A. Hasan b, A. Linhardt b, B. Ertl-Wagner c, D. Keeser b,c (a Ludwig-MaximiliansUniversität München, Klinik für Psychiatrie und Psychotherapie, München, Germany, b Ludwig-Maximilian University Munich, Department of Psychiatry and Psychotherapy, Munich, Germany, c Ludwig-Maximilian University Munich, Department for Clinical Radiology, Munich, Germany) Introduction: Anodal tDCS of the dorsolateral prefrontal cortex (DLPFC) has been associated with improvement of cognitive performance and suggested as therapeutic intervention for several neurological and psychiatric disorders. Most recently, anodal tDCS has been shown to improve deficient cognitive control in major depression. Based on previous behavioral findings and preclinical data of tDCS inducing long-term NMDA receptor and/or BDNF-dependent plasticity, anodal tDCS of the DLPFC may be theoretically suitable for enhancing the effects of psychotherapeutic interventions similar to pharmacological strategies like d-cycloserine. Objectives: To investigate whether anodal tDCS of the DLPFC applied as group intervention enhances the effect of a behavioral group therapy program for nicotine dependency. Material and methods: Following the investigation of tDCS mediated effects in resting state EEG activity and event related potentials, these effects were further characterized using resting state fMRI in healthy subjects who underwent real and sham tDCS in a randomized cross-over design. tDCS was applied for 20 min at 2 mA with the anode positioned over the left DLPFC and the cathode over the right supra-orbital region. Resting state brain activity was measured before and after tDCS with 3T fMRI. Subsequently, the same tDCS protocol was used in subjects who underwent a behavioral psychotherapy group program for nicotine dependency. tDCS is applied in a placebo-controlled, double-blind pilot study in 36 subjects who want to quit smoking. This study is still ongoing (ClinicalTrials.gov: NCT01729507). Results: In healthy subjects, significant changes of regional brain activity were found for the default mode network (DMN) and both