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Looming sounds selectively and pre-consciously enhance visual cortex excitability
Abstracts TMS Poster Only 26
Looming sounds selectively and pre-consciously enhance visual cortex excitability
Romei V1, Murray MM2, Thut G1, 1Centre for Cognitive Neuroimaging (CCNi) (Glasgow, UK); 2EEG Brain Mapping Core, Center for Biomedical Imaging and The Functional Electrical Neuroimaging Lab (Lausanne, CH); 1Center for Cognitive Neuroimaging (CCNi) (Glasgow, UK) Objective: Looming objects pose potential threats to an organism, making it advantageous for sensory systems to detect such events rapidly and efficiently. Evidence from nonhuman primates would further suggest an evolved capacity to integrate looming multisensory (auditory-visual) objects. Whether such extends to humans and what brain mechanisms contribute to such effects remain unknown. Here, we studied the impact of looming sounds on visual cortex excitability as a potential basis for rapid and efficient detection of approaching objects. Across 3 experiments, we varied sound category (looming (L), receding (R), and stationary (S)) and used phosphene detection following occipital TMS at sound offset as an index of visual cortex excitability. Method: Exp.1 (n 5 15): We tested whether L-sounds differentially increase visual cortex excitability relative to R- or S-sounds depending on sound duration (250, 500, 1000ms). Exp.2 (n 5 11): We investigated the time-course of the L-sensitive changes in visual cortex excitability (as compared to Ssounds) by presenting initial portions of a 250ms L (or S) sound (clipped in chunks of increasing length of 70 to 230ms). Exp.3 (n 5 11): We assessed performance in L-S-sound discrimination (same-different task) to compare changes in visual cortex excitability across these clipped sounds (70 to 230ms) with the corresponding probability of discriminating L-sounds. Results: Exp.1: Visual cortex excitability was differentially modulated across sound categories independently of sound duration. The most remarkable increase was observed for L-sounds, significantly exceeding the excitability increases of all the other sounds (by almost equal to 80%). Exp.2: Modulation of visual cortex excitability started to differ between Land S-sounds as early as 80ms after sound onset. Exp.3: The L-sound effect on visual cortex excitability (almost equal to 80ms) occurred prior to reliable discrimination of L-sound (almost equal to 110ms). Conclusion: L-sounds dramatically and selectively increase visual cortex excitability. This increase occurs at times when there is no perceptual L experience, is thus sensitive to only weak changes in the L-sound profile and likely to be subserved by a pre-attentive auditory ‘‘path’’ into visual cortex. This provides evidence for pre-conscious, cross-modal modulation of low-level visual cortex for boosting of visual perception by L-sounds, and possibly for multisensory L object detection in a natural environment.
247 Magnetic stimulation was performed using a Magstim Rapid 2 stimulator with a cycling frequency up to 100 Hz. The treatment was performed with a total number of magnetic stimuli ranging from 3.000 (spasticity) to 10.000 (pain) with an intensity of 80 % (pain) to 120 % (spasticity) of the resting motor threshold. EEG and blood sampling were performed before, during and after the ten day stimulation session. Levels of CPK, NSE and PL were determined as a routine analysis. Tryptophan and kynurenine and kynurenic acid were analysed using HPLC method. Correlation between alterations of neurochemical parameters and efficiency of the repetitive magnetic stimulation was searched. In three patients depression markedly improved, four patients with neuropathic pain reported significant amelioration, one a deterioration, and in one case stimulation had to be discontinued due to increased epileptic signs in the EEG. Correlations between EEG changes and neurochemical parameters did not reach significant values, likely due to the low number of cases at present.
TMS Poster Only 29
Role of cortical cell type and neuronal morphology in electric field stimulation
Radman T1, Ramos R2, Brumberg JC2, Bikson M1, Brumberg JC1, 1 Graduate Center of CUNY (New York, NY, US); 2Queens College of CUNY (Flushing, NY, US) Objective: Clinical application of transcranial magnetic stimulation (TMS) and transcranial current stimulation (TCS, encompassing transcranial direct current stimulation, cranial electrotherapy stimulation, transcranial electric stimulation, and electroconvulsive therapy) are promising noninvasive approaches for the treatment of a number of psychiatric disorders and pain. The cortex is the most common target of these non-invasive brain stimulation modalities. Cellular level studies of the electric fields, imposed by these brain stimulation modalities, state that cellular morphology predict the induced transmembrane polarization along a neuron. Cortical cell types are defined by their function and morphology. Understanding of the effects of electric fields on differing cortical cell types will lead to better, more focal non-invasive brain stimulation therapies. Method: We stimulated rat cortical brain slices in vitro using uniform electric fields and observed the electrophysiological response with whole cell patch clamp recording techniques. Intracellular dialysis of biocytin through the recording electrode allowed for analysis of cell type and morphology, and correlations with polarization induced by an electric field.
rTMS Poster Only 27
Repetitive transcranial magnetic stimulation for the treatment of depression, pain and spasticity – correlations with neurochemical parameters
Eigner S1, Kepplinger B2, Semler B3, Baran H3, 1Landesklinikum MauerAmstetten (Amstetten, AT); 2Karl Landsteiner Research Insitute Mauer (Mauer-Amstetten, AT); 3Veterinary Medical University (Vienna, AT) Transcranial magnetic stimulation, a non invasive technique for stimulation of the brain has been suggested to be effective for the treatment of depression, neuropathic pain and spasticity. This study was designed to find correlations between clinical outcome, EEG and neurochemical and/or chemical markers as neuron specific enolase (NSE), prolactin (PL), tryptophan with kynurenine metabolites and CPK. Magnetic stimulation was administered to patients with depression (n 5 5), neuropathic pain (n 5 7) and spasticity (n 5 11).
Synaptic contributions were investigated using glutamatergic transmission blockers CNQX (AMPA) and APV (NMDA). Result: We developed measures of neuronal morphology, incorporating neuronal branching angle to the induced electric field and branch diameter,
Looming sounds selectively and pre-consciously enhance visual cortex excitability
Romei V1, Murray MM2, Thut G1, 1Centre for Cognitive Neuroimaging (CCNi) (Glasgow, UK); 2EEG Brain Mapping Core, Center for Biomedical Imaging and The Functional Electrical Neuroimaging Lab (Lausanne, CH); 1Center for Cognitive Neuroimaging (CCNi) (Glasgow, UK) Objective: Looming objects pose potential threats to an organism, making it advantageous for sensory systems to detect such events rapidly and efficiently. Evidence from nonhuman primates would further suggest an evolved capacity to integrate looming multisensory (auditory-visual) objects. Whether such extends to humans and what brain mechanisms contribute to such effects remain unknown. Here, we studied the impact of looming sounds on visual cortex excitability as a potential basis for rapid and efficient detection of approaching objects. Across 3 experiments, we varied sound category (looming (L), receding (R), and stationary (S)) and used phosphene detection following occipital TMS at sound offset as an index of visual cortex excitability. Method: Exp.1 (n 5 15): We tested whether L-sounds differentially increase visual cortex excitability relative to R- or S-sounds depending on sound duration (250, 500, 1000ms). Exp.2 (n 5 11): We investigated the time-course of the L-sensitive changes in visual cortex excitability (as compared to Ssounds) by presenting initial portions of a 250ms L (or S) sound (clipped in chunks of increasing length of 70 to 230ms). Exp.3 (n 5 11): We assessed performance in L-S-sound discrimination (same-different task) to compare changes in visual cortex excitability across these clipped sounds (70 to 230ms) with the corresponding probability of discriminating L-sounds. Results: Exp.1: Visual cortex excitability was differentially modulated across sound categories independently of sound duration. The most remarkable increase was observed for L-sounds, significantly exceeding the excitability increases of all the other sounds (by almost equal to 80%). Exp.2: Modulation of visual cortex excitability started to differ between Land S-sounds as early as 80ms after sound onset. Exp.3: The L-sound effect on visual cortex excitability (almost equal to 80ms) occurred prior to reliable discrimination of L-sound (almost equal to 110ms). Conclusion: L-sounds dramatically and selectively increase visual cortex excitability. This increase occurs at times when there is no perceptual L experience, is thus sensitive to only weak changes in the L-sound profile and likely to be subserved by a pre-attentive auditory ‘‘path’’ into visual cortex. This provides evidence for pre-conscious, cross-modal modulation of low-level visual cortex for boosting of visual perception by L-sounds, and possibly for multisensory L object detection in a natural environment.
247 Magnetic stimulation was performed using a Magstim Rapid 2 stimulator with a cycling frequency up to 100 Hz. The treatment was performed with a total number of magnetic stimuli ranging from 3.000 (spasticity) to 10.000 (pain) with an intensity of 80 % (pain) to 120 % (spasticity) of the resting motor threshold. EEG and blood sampling were performed before, during and after the ten day stimulation session. Levels of CPK, NSE and PL were determined as a routine analysis. Tryptophan and kynurenine and kynurenic acid were analysed using HPLC method. Correlation between alterations of neurochemical parameters and efficiency of the repetitive magnetic stimulation was searched. In three patients depression markedly improved, four patients with neuropathic pain reported significant amelioration, one a deterioration, and in one case stimulation had to be discontinued due to increased epileptic signs in the EEG. Correlations between EEG changes and neurochemical parameters did not reach significant values, likely due to the low number of cases at present.
TMS Poster Only 29
Role of cortical cell type and neuronal morphology in electric field stimulation
Radman T1, Ramos R2, Brumberg JC2, Bikson M1, Brumberg JC1, 1 Graduate Center of CUNY (New York, NY, US); 2Queens College of CUNY (Flushing, NY, US) Objective: Clinical application of transcranial magnetic stimulation (TMS) and transcranial current stimulation (TCS, encompassing transcranial direct current stimulation, cranial electrotherapy stimulation, transcranial electric stimulation, and electroconvulsive therapy) are promising noninvasive approaches for the treatment of a number of psychiatric disorders and pain. The cortex is the most common target of these non-invasive brain stimulation modalities. Cellular level studies of the electric fields, imposed by these brain stimulation modalities, state that cellular morphology predict the induced transmembrane polarization along a neuron. Cortical cell types are defined by their function and morphology. Understanding of the effects of electric fields on differing cortical cell types will lead to better, more focal non-invasive brain stimulation therapies. Method: We stimulated rat cortical brain slices in vitro using uniform electric fields and observed the electrophysiological response with whole cell patch clamp recording techniques. Intracellular dialysis of biocytin through the recording electrode allowed for analysis of cell type and morphology, and correlations with polarization induced by an electric field.
rTMS Poster Only 27
Repetitive transcranial magnetic stimulation for the treatment of depression, pain and spasticity – correlations with neurochemical parameters
Eigner S1, Kepplinger B2, Semler B3, Baran H3, 1Landesklinikum MauerAmstetten (Amstetten, AT); 2Karl Landsteiner Research Insitute Mauer (Mauer-Amstetten, AT); 3Veterinary Medical University (Vienna, AT) Transcranial magnetic stimulation, a non invasive technique for stimulation of the brain has been suggested to be effective for the treatment of depression, neuropathic pain and spasticity. This study was designed to find correlations between clinical outcome, EEG and neurochemical and/or chemical markers as neuron specific enolase (NSE), prolactin (PL), tryptophan with kynurenine metabolites and CPK. Magnetic stimulation was administered to patients with depression (n 5 5), neuropathic pain (n 5 7) and spasticity (n 5 11).
Synaptic contributions were investigated using glutamatergic transmission blockers CNQX (AMPA) and APV (NMDA). Result: We developed measures of neuronal morphology, incorporating neuronal branching angle to the induced electric field and branch diameter,