Effects of excessive sugar consumption on social recognition behavior of rats exposed to prolonged stress
Büyükgüdük, İlkim
Objective: As a result of non-tolerable toxic stress caused by negative life experiences, the first symptoms causing impairment in functionality of an individual are seen in social field. we aim to investigate the alterations in the social recognition and memory tests in excessive sugar consumed animals exposed to single prolonged stress. Methods: Adult female rats (n=15) were divided into two groups and 10% corn syrup was added to the diet of the experimental group for 10 days, while only water and standard pellets were given to the controls. At the end of the diet, single prolonged stress protocol (2 hours immobilization, 20 minutes forced swim and ether until anesthesia) was applied to the animals. Animals were kept under control conditions for 7 days. Animals were conditioned with high...
Non-invasive vagus nerve stimulation in a hungry state decreases heart rate variability
Büyükgüdük, ilkim | Yanık, Hüseyin | Yılmaz, Dilan Dneiz | Yar, Berçem | Değirmenci, Evren | Dal, Uğur | Geraldine Veldhuizen, Maria
Vagus nerve signals from the gut to brain carry information about nutrients and drive food reward. Such signals are disrupted by consuming large amounts of high-calorie foods, necessitating greater food intake to elicit a similar neural response. Non‐invasive vagus nerve stimulation (nVNS) via a branch innervating the ear is a candidate treatment for obesity in humans. There is disagreement on the optimal location of nVNS in the ear for experimental and clinical studies. There are also no studies comparing nVNS in hungry and post-prandial states. We aimed to compare ear position(s) for nVNS and explore the effects of nVNS during hungry and post-prandial states on proxies for autonomic outflow (heart-rate variability) and efferent metabolism (gastric wave frequency and resting energy expend...
Transcutaneous Vagus Nerve Stimulation Enhances Probabilistic Learning
Büyükgüdük, İlkim | Geraldine Veldhuizen, Maria
tVNS enhances various memory and learning mechanisms, but there is inconclusive evidence on whether probabilistic learning can be enhanced by tVNS. Here, we tested a simplified version of the probabilistic learning task with monetary rewards in a between-participants design with left and right-sided cymba conchae and tragus stimulation (compared to sham stimulation) in a sample of healthy individuals (n = 80, 64 women, on average 26.38 years old). tVNS enhances overall accuracy significantly(p = 4.09 x 10⁻⁰⁴) and reduces response times (p = 1.1006 x 10⁻⁴⁹) in the probabilistic learning phase. Reinforcement learningmodelling of the data revealed that the tVNS group uses a riskier strategy, dedicates more time to stimulus encoding and motorprocesses and exhibits greater reward sensitivity re...
Corticospinal motor neuron specific transduction of the TARDBP gene via viral vectors
Büyükgüdük, İlkim
Objective: Recent studies show that mutations and overexpression of the TARDBP gene causes pathological aggregates and inclusion bodies in neurons. This is one of the underlying causes of the progressive neuronal degeneration and apoptosis seen in motor neuron diseases. In this study, we investigated the morphological changes in the rat motor cortex after transduction of neurons by viral vectors expressing either full-length hTDP-43 or nuclear localization sequence-deleted hTDP-43 (hTDP-43-ΔNLS). Methods: Experimental (hTDP-43 and hTDP-43-ΔNLS) and control (SF injected) groups of 4 week-old Sprague-Dawley rats (n=6, for each group) received intravenous injection of viral vectors (AAV2-9 serotype, 1.77x1012 vg/kg) designed under the control of a specific promoter (ubiquitin carboxyl-termin...
CAN NON-INVASIVE VAGUS NERVE STIMULATION CONDITION PREFERENCE FOR NEW FLAVORS PAIRED WITH LOW-FAT FOODS?
Büyükgüdük, İlkim | Geraldine Veldhuizen, Maria | Yılmaz, Dilan Deniz | Dal, Uğur
Conditioned flavor preference can be formed when a novel flavor is associated with for example palatable taste and/ or with positive post-digestive effects. Recent research on the vagus nerve (VN) using chemogenetic and optogeneti stimulation has shown that vagal gut-brain communication underlies this learning. If VN activity triggers food reward, we predict that non-invasive VN stimulation (nVNS, compared to pseudo-stimulation) will condition liking for new flavors paired with low-fat foods. In order to select flavors for conditioning, 17 participants tasted and rated 10 flavors using the sip and-spit method. The participants rated liking and wanting. Two flavors that are similarly near to neutral in liking were chosen for the conditioning sessions. To induce associative conditioning, we ...
Alterations in motor functions of rats after systemic delivery of genes encoding native or mutant transactive response DNA-binding protein-43 (TDP-43)
Büyükgüdük, İlkim
Objective: Transactive response-DNA binding proteinopathy (TDP-43) has become a hallmark feature in motor neuron diseases. Not only overexpression, but also deletion of the nuclear localization signal (NLS) causes proteinopathic alterations. We employed viral vector mediated gene transfer method for delivery of genes encoding native or mutant TDP-43 to assess motor functions of young adult male and female Sprague-Dawley rats. Methods: Motor neuron specific targeting of AAV9 vectors were achieved by using a cell type specific promoter (UCHL1). While control animals received SF injection (n=10), experimental groups were injected by either native or NLS-deleted viruses (1.77×1012 vg/kg, n=7/each group), on postnatal day 30. Following systemic injection of viruses, motor coordination of anim...