Dr. Dushanova’s is in Bulgarian Academy of Sciences, Bulgaria. She has research interests are in motor neurophysiology, pathophysiology of Parkinson’s disease and in the development of approaches for diagnostics. Her works span human and non-human primate research, computational modeling and simulations. She received her MS degree from Sofia University, Bulgaria, Predoctoral fellow by Prof. Pfurtscheller at Department of Medical Informatics, Ludwig Boltzmann Institute for Medical Informatics and Neuroinformatics, Technical University Graz, Austria, PhD from Institute of Neurobiology, Bulgarian Academy of Sciences and studied neurophysiology under Prof. J.P. Donoghue in the Neuroscience Department of Brown University, RI USA. Assoc. Prof. J. Dushanova’s research is in the field of movement disorders and she has been involved in electroencephalography research and practice since 1994.
The brain as a system with gradually decreasing resources by age maximizes its performance by neural networks reorganization for greater efficiency of neuronal oscillations in a given frequency band. Event-related high frequency-band responses, however, have not enough been investigated in the sensory/cognitive mechanisms accompanying aging. Method: The aged effect on the brain electrical activitywas studied in auditory discrimination task (low–frequency and high–frequency tone) at particular cortical locations in beta (β1:12.5–20; β2:20.5–30 Hz) and gamma frequency bands (γ1:30.5–49; γ2:52–70 Hz) during sensory (post–stimulus interval 0–250 ms) and cognitive processing (250–600ms). Results: The beta1 activity less affected by age (only at temporal and parietal area) during sensory processing. The reduced beta1 was more widespread during cognitive processing. This difference increased in fronto–parietal direction more expressed after a high-frequency tone. Beta2 and gamma activity are more pronounced with a progressive age during sensory processing. They reduced by age on cognitive processes. Reducing regional-process specificity with progressing age characterized age-related and tone-dependent beta2 changes during sensory processing. Only the elderly showed higher frontal gamma1 activity during sensory processing. The centres of gamma2 shifted from posterior to anterior brain regions with advancing age. Conclusion: With increasing age, the frontal brain areas become more sensitive to high-tone discrimination and hand reaction choice. The aged influence was higher on the cognitive processes than on the perceptual ones.
Ewelina Bratek, is a student at Department of Neurochemistry at Mossakowski Medical Research Centre, Poland
Hypoxic-ischemic encephalopathy is an abnormal neurobehavioral state which results fromimpaired cerebral blood flow at the time around birth. This condition may cause neonatal death or be manifested later as cerebral palsy or mental deficiency. Recent investigations have not provided us with promising neuroprotective compounds to reduce perinatal hypoxic-ischemic (HI) brain injury. It was shownrecentlythat mGluR2/3 activation before or after ischemic insult results in neuroprotection but the exact mechanism of this effect is not clear. The aim of present study was to investigate whether mGluR2/3 activation after hypoxia-ischemia reduces brain damage and if the activation of antioxidant enzymes and decrease of oxidative stress participate in observed effects.We used an animal model of hipoxia-ischemia (H-I) on 7-day old rat pups. Animals were anesthetized and the left common carotid artery was isolated and double – ligated and then cut between the ligatures. After completion of the surgical procedure the pups were subjected to hypoxia(7.2% -7.4% oxygen in nitrogen for 75 min at 35 ˚C). Control pups were sham-operated (anaesthetized and left c.c.a. dissected, but not ligated). Animals were injected intra peritoneal with specific mGluR2 (LY 379268) and mGluR3 (NAAG) agonists 1 h or 6 h after H-I (5 mg/kg of body weight). Weight deficit of the ischemic brain hemisphere, radical oxygen species (ROS) content, activity of antioxidant enzymes (superoxide dismutase - SOD, Glutatione peroxidase - GPx, catalase - CAT) and level of reduced glutathione (GSH) were measured. Our results show a neuroprotective effect of mGluR 2/3 agonists. Both agonists applied decreased brain tissue weight loss in ischemic hemisphere independently on the time of application (from 40% in H-I to 15 - 20% in treated).Our results show that both mGluR2/3 antagonists reduce ROS level in the injured hemisphere.H-I resulted inincreased activity of SOD in the injured hemisphere, whichwasreduced by mGluR2/3 agonists application 1h or 6 h after H-I. The activity of glutathione peroxidase (GPX) was also increased by H-I and its activity was decreased by both agonists. The decrease of GSH level observed in ischemic hemisphere was not observed after agonists application, the effect was better expressed when agonists were administered 1 h after H-I. Application of agonists resulted also in decrease in CATactivity. Conclusions The results show that activation of mGluR2 and mGluR3 in a short time after H-I insult triggered neuroprotective mechanisms, which probably partly engage defence against oxidative stress and ROS production. The effect is more distinct when agonists are applied in a short time after H-I This work was made under MMRC-KNOW 2013-2017 project.