Visuospatial Perception:from Behavior to Brain

We use visual spatial perception to localize ourselves in our environment, to direct our attention, and to reach out to and grasp objects. In this thesis, I aimed to better understand the role of response type and the various aspects of our visual scene in human visual perception. I found that making eye-movements or not to indicate the identity and location of objects did not affect human performance. This contrasts previous suggestions in the literature. It is important, as it means eye-movements can be used to accurately assess human visual perception. In addition, using functional magnetic resonance imaging (fMRI), I found that it is possible to much more accurately map the spatial representation of the visual world in the visual brain by using stimulation method based on orientation rather than luminance contrast. The new method better reveals various properties of the spatial organization of the human visual cortex

Effects of Dietary Pelargonium sidoides Extract on Growth Performance in Common Carp, Cyprinus carpio

The effects of graded dietary supplementation of Pelargonium sidoides extract on growth performance, feed utilization, and body composition in common carp, Cyprinus carpio, were preliminarily evaluated. Fish (0.67±0.05 g) were fed experimental diets containing 0, 1, 3, or 5 ml/100 g P. sidoides extract for 90 days. Growth rate significantly (p<0.05) increased in carp fed supplemented diets. The specific growth rate ranged from 2.87±0.09 in the control to 3.41±0.11 in fish fed the diet supplemented with 5 ml P. sidoides. The feed conversion ratio, protein efficiency ratio, and apparent net protein utilization were significantly better in groups fed diets with 3 or 5 ml P. sidoides extract than in the control or 1 ml group. The highest protein content (19.65%) was obtained with 3 ml supplementation. The present study shows that P. sidoides extract has a positive effect on carp growth and feed utilization with no apparent effects on health status

A second-order orientation-contrast stimulus for population-receptive-field-based retinotopic mapping

Visual field or retinotopic mapping is one of the most frequently used paradigms in fMRI. It uses activity evoked by position-varying high luminance contrast visual patterns presented throughout the visual field for determining the spatial organization of cortical visual areas. While the advantage of using high luminance contrast is that it tends to drive a wide range of neural populations - thus resulting in high signal-to-noise BOLD responses - this may also be a limitation, especially for approaches that attempt to squeeze more information out of the BOLD response, such as population receptive field (pRF) mapping. In that case, more selective stimulation of a subset of neurons - despite reduced signals - could result in better characterization of pRF properties. Here, we used a second-order stimulus based on local differences in orientation texture - to which we refer as orientation contrast - to perform retinotopic mapping. Participants in our experiment viewed arrays of Gabor patches composed of a foreground (a bar) and a background. These could only be distinguished on the basis of a difference in patch orientation. In our analyses, we compare the pRF properties obtained using this new orientation contrast-based retinotopy (OCR) to those obtained using classic luminance contrast-based retinotopy (LCR). Specifically, in higher order cortical visual areas such as LO, our novel approach resulted in non-trivial reductions in estimated population receptive field size of around 30%. We discuss how OCR - by limiting receptive field scatter and reducing BOLD displacement - may result in more accurate pRF localization as well. We conclude that using our approach, it is possible to selectively target particular neuronal populations, opening the way to use pRF modeling to dissect the response properties of more clearly-defined neuronal populations in different visual areas.Comment: Yildirim, F., et al., A second-order orientation-contrast stimulus for population-receptive-field-based retinotopic mapping, NeuroImage (2017

An Exploratory Analysis of the Neural Correlates of Human-Robot Interactions With Functional Near Infrared Spectroscopy

Functional near infrared spectroscopy (fNIRS) has been gaining increasing interest as a practical mobile functional brain imaging technology for understanding the neural correlates of social cognition and emotional processing in the human prefrontal cortex (PFC). Considering the cognitive complexity of human-robot interactions, the aim of this study was to explore the neural correlates of emotional processing of congruent and incongruent pairs of human and robot audio-visual stimuli in the human PFC with fNIRS methodology. Hemodynamic responses from the PFC region of 29 subjects were recorded with fNIRS during an experimental paradigm which consisted of auditory and visual presentation of human and robot stimuli. Distinct neural responses to human and robot stimuli were detected at the dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) regions. Presentation of robot voice elicited significantly less hemodynamic response than presentation of human voice in a left OFC channel. Meanwhile, processing of human faces elicited significantly higher hemodynamic activity when compared to processing of robot faces in two left DLPFC channels and a left OFC channel. Significant correlation between the hemodynamic and behavioral responses for the face-voice mismatch effect was found in the left OFC. Our results highlight the potential of fNIRS for unraveling the neural processing of human and robot audio-visual stimuli, which might enable optimization of social robot designs and contribute to elucidation of the neural processing of human and robot stimuli in the PFC in naturalistic conditions

Investigation on the Effects of 12 Days Intensive Competition on Some Blood Parameters of Basketball Players

The aim of this study is  to investigate the effect of intensive basketball competitions (10 official basketball games in 12 days intensive competition period) on blood parameters of basketball players. Blood samples were taken from the basketball players of the university team. The players were training regularly and they had no regular health problems. The average age of the players was 22,80 ± 3,20 years and the average height was 185,83 ± 7,57 cm. This study was performed on 10 volunteer basketball players. Blood samples were taken before (24 hours), after (24 hours) and during the intensive competitions. Descriptive statistics (mean and standard deviation) were applied to the data, Wilcoxon two realized sample test was used to compare the values before and after the competition period. When comparing the blood values before and after the competition period, there was significant increase in prevalence of Fe, albumin, AST, ALT, LDL, HDL, MCH, MCHC and the values of UIBC, creatinine, HCT and MPV were significantly low before the competition; (P <0.05).The findings show that the physiological characteristics of basketball players are influenced by intensive competitions. In the literature, the physiological effects of regular and single-session exercises have been investigated in many studies. However, the data about the physiological effects of intensive competition periods are rather limited. A better understanding of these influences will guide the event organizers and coaches to plan the competitions and it will facilitate the preparation of the sportsmen for this intensive competition periods

Efficacy of omalizumab in patients with chronic spontaneous urticaria and its association with serum IgE levels and eosinophil count

Chronic spontaneous urticaria can be treated with several drugs such as antihistamines, leukotriene antagonists, cyclosporine, doxepin, hydroxychloroquine, colchicine, and corticosteroids. However, treatment-resistant urticaria significantly reduces quality of life. In recent years, omalizumab has been considered to be an effective treatment option in treatment-resistant cases. We aimed to investigate the clinical efficacy of omalizumab in urticaria and its possible association with serum IgE levels, total eosinophil counts, and basophil percentages. Medical records of 11 patients with chronic spontaneous urticaria treated with omalizumab were reviewed retrospectively. Treatment response, urticaria activity score, serum basophil percentages, eosinophil, and IgE levels evaluated before and at the end of the therapy. Ten patients healed completely with omalizumab. One patient did not respond to therapy. No correlation was observed between serum IgE levels and treatment outcome. However, serum eosinophil levels decreased and basophil percentages increased with omalizumab treatment. Omalizumab is a safe and effective treatment choice in patients with chronic spontaneous urticaria. We suggest that omalizumab may have an effect in the treatment of urticaria through eosinophils.</p