Corticospinal and intracortical excitability are excitability measures of the central nervous system responsible for motor generation, and are studied for their contribution to fine motor skill execution and learning. Since the need for proper execution of fine motor skills is ever-present and necessary for everyday life, identification of physiological pathways that may disrupt or enhance corticospinal and intracortical excitability is an important research topic. This thesis investigates the effects of baroreceptor unloading on corticospinal and intracortical excitability during various motor tasks. Baroreceptor unloading is a physiological response to common hemodynamic stress (e.g. hypovolemia and orthostasis). The motor tasks investigated are complete muscular relaxation, individual isometric low-force contraction of a muscle, and an isometric co-contraction of a muscle in a joint-stabilizing task. The effects of baroreceptor unloading on corticospinal and intracortical excitability appear to be very task specific. The results are discussed in view of available pharmacological and physiological research, and potential neural pathways for the observed effects are suggested. The overall conclusion is that baroreceptor unloading increases corticospinal excitability and decreases intracortical inhibition in a resting muscle, does not produce any observable effects during individual muscle activity, and decreases corticospinal excitability during joint-stabilizing co-contraction.

Objectives: High frequency left-sided (HFL) and low frequency right-sided (LFR) unilateral repetitive transcranial magnetic stimulation (rTMS) are efficacious in treatment-resistant major depression (TRD). Similar benefit has been suggested for sequential bilateral rTMS (LFR then HFL). Therefore, this study evaluated the efficacy of HFL and sequential bilateral rTMS compared to sham in TRD. Methods: Seventy-four subjects between the ages of 18 and 85 with TRD and a 17-item Hamilton Depression Rating Scale (HDRS) greater than 21 were randomized to receive unilateral, bilateral, or sham rTMS. Remission rates were compared among the three groups. Results: Remission rates differed significantly among the three groups. The remission rate was significantly higher in the bilateral group (34.6%) than the unilateral (4.5%) and sham (5.0%) groups. The remission rate in the unilateral group did not differ from sham group. Conclusion: These findings warrant larger controlled studies that compare the efficacy of sequential bilateral rTMS and HFL rTMS in TRD.

Objectives: High frequency left-sided (HFL) and low frequency right-sided (LFR) unilateral repetitive transcranial magnetic stimulation (rTMS) are efficacious in treatment-resistant major depression (TRD). Similar benefit has been suggested for sequential bilateral rTMS (LFR then HFL). Therefore, this study evaluated the efficacy of HFL and sequential bilateral rTMS compared to sham in TRD. Methods: Seventy-four subjects between the ages of 18 and 85 with TRD and a 17-item Hamilton Depression Rating Scale (HDRS) greater than 21 were randomized to receive unilateral, bilateral, or sham rTMS. Remission rates were compared among the three groups. Results: Remission rates differed significantly among the three groups. The remission rate was significantly higher in the bilateral group (34.6%) than the unilateral (4.5%) and sham (5.0%) groups. The remission rate in the unilateral group did not differ from sham group. Conclusion: These findings warrant larger controlled studies that compare the efficacy of sequential bilateral rTMS and HFL rTMS in TRD.

Currently, when there is a reduction of soil water due to drought, is appropriate measure to start systematic collection of data on soil moisture. In this work the soil moisture content was measured on the Litovicko-Šárecký brook basin near a small water reservoir Strand. The datat were collected by direct method, which mean direct soil sampling and subsequent analysis, and indirect methods concretely gathering data by TMS datalogger. Measured data from direct and indirect methods are essentially agree in this, that small water reservoir Strnad hasnt effect at soil moisture in a distance 200 m. The last part describes the analysis of grain soils using aerometrical methods. The resulting soil types are further used for calibrating the TMS datalogger.

Swallowing is a complex neurophysiological process involving the activation of several components of the central nervous system with bilateral but asymmetric representations of swallowing musculature in the motor cortex. Difficulty in swallowing (dysphagia) in stroke patients has been reported by up to 50% of victims, and can increase morbidity and mortality in this population due to the development of aspiration pneumonia and malnutrition. One of the common factors that predispose patients to dysphagia after a stroke is believed to be the reduced sensory awareness in the oropharyngeal area, which affects the swallowing process. The uses of diet modification to reduce thin liquid aspiration have gained interest but are often unpalatable or have limited success. Carbonated liquid have shown some beneficial effects in swallowing behaviour. However, there is very little evidence to support this intervention. Therefore, the aim of this thesis is to investigate the neurophysiological and behavioural effects of carbonated liquids on swallowing in healthy volunteers.The effects of carbonated solutions on swallowing performance compared to non-carbonated solutions (still water) was investigated in a pilot study and (still water and citric acid) in the main study using reaction time task (chapter 2). Carbonation appears to alter swallowing performance compared to other liquids by improving complex tasks. In addition, beneficial neurophysiological effects of carbonated liquids were evident after 10 minutes of carbonated liquid swallowing compared to still water and citric acid solution in healthy volunteers (chapter 3).In chapter 4, the response of the healthy swallowing motor cortex to carbonated liquids following application of a virtual lesion compared to still water and saliva swallowing, was investigated. Carbonated liquids were able to reverse the inhibitory effect induced by 1 Hz rTMS to the dominant pharyngeal motor representation. Moreover, the beneficial effects of carbonated liquids on swallowing performance, measured with a swallowing reaction times task after application of a virtual lesion was observed in a pilot investigation in healthy volunteers (chapter 5). These data demonstrate that carbonated liquids have beneficial neurophysiological and swallowing performance effects and support notion that the chemical properties of carbonated liquids may provide the required peripheral sensory information that alter the brain swallowing function, which leads to an improvement in the swallowing performance of stroke dysphagic patients. These data lay the foundation for considering the use of carbonation as facilitating stimuli in dysphagic patients.

Angsterkrankungen stellen einen großen Anteil an psychischen Erkrankungen dar und gehen zum Teil mit großem Leidensdruck einher. Da die leitliniengerechte Therapie mit hohen Rückfallraten und ca. 25% Nonrespondern einhergeht, stellt sich die Frage nach alternativen Behandlungsmethoden. Transkranielle Magnetstimulation findet als nichtinvasive Behanslungsmethode zunehmend Anwendung bei neurologischen und psychiatrischen Erkrankungen. In der vorliegenden randomisierten, kontrollierten Studie wurde die Wirkung der TMS auf den frontotemporalen (FTC) und dorsolateralen präfrontalen Cortex (dlPFC) untersucht. Dazu wurden 42 gesunde Probanden zwischen 18 und 59 Jahren zur Hälfte TMS-stimuliert, die andere Hälfte wurde scheinstimuliert. Vor und nach Stimulation bzw. Placebostimulation wurde die Aktivität von FTC und dlPFC mit Nah-Infrarotspektroskopie (NIRS) während der Durchführung des Verbal Fluency Tasks (VFT) gemessen. In dieser Studie konnte keine Veränderung der hämodynamischen Gehirnaktivität durch TMS nachgewiesen werden, jedoch äußerten die Probanden der Stimulationsgruppe im Gegensatz zu den Probanden der Placebogruppe, Nebenwirkungen wie Schmerzen oder Muskelzucken verspürt zu haben. Die während des VFT laufende NIRS zeigte eine signifikant höhere Durchblutung und damit Aktivierung des linken FTC im Seitenvergleich und eine signifikant höhere Aktivierung während der semantischen als bei der phonemischen VFT-Bedingung, analog zu früheren, vergleichbaren Untersuchungen. Die Frage, ob sich TMS als mögliche Behandlungsmethode bei Angsterkrankungen eignet, lässt sich anhand der hier vorliegenden Studie nicht abschließend beantworten. / Anxiety disorders constitute a large proportion of mental illnesses and are often accompanied by great strain imposed by suffering. Since guideline-based therapy is characterised by high relapse rates and about 25% of non-responders, the question of alternative treatment methods arises. Transcranial magnetic stimulation as a non-invasive treatment method is being increasingly applied to treat neurological and psychiatric diseases. In the presented randomised, controlled study, the effect of TMS on the frontotemporal (FTC) and dorsolateral prefrontal cortex (dlPFC) was examined. For this purpose, one half of 42 healthy volunteers between 18 and 59 years of age received TMS stimulation while the other half received sham stimulation. Before and after both real and placebo stimulation, the activity of FTC and dlPFC was measured with near-infrared spectroscopy (NIRS) during the execution of Verbal Fluency Tasks (VFT). In this study, no change in hemodynamic brain activity through TMS could be detected. However, contrary to the placebo group volunteers, the stimulation group volunteers reported side effects such as pain or muscle twitching. The NIRS running during VFT showed a significantly increased blood flow and thus an activation of the left FTC in the side comparison, as well as a significantly enhanced activation during the semantic VFT condition in comparison with the phonemic one, analogous to previous comparable examinations. The question of whether TMS presents itself as a potential treatment for anxiety disorders can not be conclusively answered on the basis of the study presented here.

Over the past decade, efforts have been made to assess the positive therapeutic effects of transcranial magnetic stimulation (TMS) by altering the excitability of the brain. We conducted a double-blind, placebo-controlled study to assess the efficacy of right prefrontal slow repetitive TMS in patients with treatment refractory major depression. This pilot study supports the therapeutic potential of rTMS in the low-frequency range of 1 Hz on right prefrontal cortex for the treatment of refractory major depression. Additional studies will be necessary to assess the efficacy of rTMS with different indices (frequency, intensity, and stimulation site) for major depression and other psychiatric diseases.

Transactive memory, the transmission and use of knowledge between two or more people, is an important construct to consider when studying work teams. This thesis reviews the literature on transactive memory systems (TMS) in order to summarize what is currently known about TMS and to identify gaps in the literature in need of further investigation. Past TMS research is reviewed according to the operational definitions, antecedents, team processes, outcomes, team performance, and boundary conditions. TMS is most frequently operationalized using Lewis' (2003) TMS scale. Research has focused on three types of antecedents: Communication, Team Characteristics, and Facilitation of TMS. Two common types of team processes found were coordination and team monitoring & backup behavior. Outcomes frequently focused on were team cognition, and team effectiveness. Team performance was ubiquitous in almost all the literature. Boundary conditions, however, varied considerably

A longstanding question in studies of cortical stimulation has been how does stimulation affect brain functioning and cognition, and what are its mechanisms of action. Brain stimulation has been traditionally seen either as a disrupting intervention or as a procedure to enhance cortical excitability and promote improvement in various modality from motor to visual performance. In vision, several hypotheses have been proposed and many experimental paradigms have been used to study how transcranial magnetic stimulation (TMS) and direct current stimulation, particularly transcranial random noise stimulation (tRNS) affect visual discrimination. Psychophysical paradigms are particularly useful to measure visual performance, whereby a stimulus is progressively changed from easy to difficult to perceive it, and accuracy threshold can be measured by titrating the stimulus discriminability. Stimuli that vary in contrast are typically used to study low-level visual functions and it is well known that neurons within the early visual areas in the brain, and primarily V1, are tuned to stimuli involved in contrast discrimination. Here we used an orientation discrimination task to study changes in contrast detection by varying stimulus contrast across different levels (Experiment 1, Chapter 2). We used neuro-navigated single-pulse TMS at different intensities to determine whether behavioral response changed linearly as a function of stimulus discriminability independently of TMSintensity, or whether TMS affected behavior depending on TMS intensity and contrast level. Moreover, we tested whether TMS had an effect selective for the field contralateral to stimulation or whether effects could be seen across the entire visual field. Single pulse TMS was delivered to left V1 while participants performed a 2-alternative forced choice orientation discrimination (OD) of one of two Gabor patches presented on either side of fixation at 5 contrast levels and 4 TMS intensities. Participants' performance on OD increased at all contrast levels in the right visual field (contralateral to stimulation) at 80% of phosphene thresholds (PT, individually measured at baseline). Furthermore, when TMS was delivered at 60% of PT, we found improved performance in the right visual field that was selective for the medium contrast, while performance increased at the highest contrast irrespective of TMS intensity, in the field ipsilateral to stimulation, thus both visual fields were affected by TMS, albeit differently. Since the improvement effects might be explained as the result of added noise to the system that paradoxically improves performance for justbelow threshold stimuli (middle contrasts), in Experiments 1 and 2 (Chapter 3) we used transcranial random noise stimulation, a neuromodulation procedure known to enhance cortical excitability when delivered at high frequencies, to further test the hypothesis that brain stimulation might work through a mechanism of stochastic resonance, whereby adding noise to a nonlinear system, the brain in our case, might paradoxically promote better performance by enhancing stimulus discriminability. This might happen only for selective stimulus intensities and stimulation strength. Based on previous successful work, we tested contrast discrimination changes as a function of four different tRNS low intensity levels of stimulation, and we found a decrease in performance selective for the condition with subthreshold stimuli and at .750 mA stimulation intensity. This result might indicate that low intensity stimulation is not enough to promote enhancement of stimuli under the stochastic mechanism effect, thereby suggesting that higher ranges of stimulation are necessary to create the optimal conditions for improvement.

ABSTRACT In the context of increasing incidence of stroke (but also an increasing rate of survival), non-invasive brain stimulation techniques (NIBS) are more frequently used for patients with post-stroke aphasia (PWA) and post-stroke depression (PSD). NIBS techniques, modulating brain plasticity, might offer valid, alternative therapeutic strategies. The aim is to reach a better outcome because treatment of aphasia can also improve post-stroke depression and vice versa. Based on two literature reviews on NIBS effects on PSD and post-stroke aphasia the conclusion is that, although the field is relatively new, and many more investigations with larger samples of patients are required, transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) clinical application is well tolerated, safe, and feasible. Starting from these encouraging data, we used a combination of TMS and electroencephalography (EEG) to explore the excitability modulation before and after active (20 sessions) and sham (20 sessions) tDCS in a double-blind crossover experiment. Four chronic non fluent PWA underwent 8 weeks of verbal exercises coupled with tDCS over the perilesional areas close to the left inferior frontal gyrus. To evaluate changes induced by tDCS, TMS-EEG responses over Brodmann area 6 (BA6) were computed using five different parameters. In addition, these data were compared with those recorded from a matched control group. The results indicated a slight improvement after tDCS stimulation (as compared to sham) for patients with Broca’s aphasia, but not for those with global aphasia. Also, TMS-evoked EEG responses recorded from the ipsilesional hemisphere were abnormal in individuals with chronic post-stroke aphasia (slower and simple responses with higher amplitudes) when compared to responses from the contralesional hemisphere and from the control group. Critically, the Global Mean Field Power (GMFP), Local Mean Field Power (LMFP) and Natural Frequency values were modulated by anodal tDCS. Despite these interesting results, further data are needed in order the obtain more direct, stronger evidence linking behavioral tDCS effects and neurophysiological data.