[show abstract][hide abstract] ABSTRACT: Some evidence suggests that sleep deprivation might impair synaptic plasticity and produce oxidative stress in the hippocampus. However it is not clear whether impairment of long-term potentiation depends on the oxidative stress evoked by sleep deprivation protocol. In this study we aimed to investigate the effects of a 21-day sleep deprivation period on long-term plasticity taking into account the stressful effect of sleep deprivation. Sleep deprivation was carried out using the multiple platforms method on adult male Wistar rats. Long-term potentiation was studied in the medial perforant pathway-dentate gyrus synapses. Elevated T test was applied, and blood corticosterone levels were measured. Lipid peroxidation products in whole brain and hippocampus were determined. No significant difference was found between the sleep deprived, pedestal and cage control groups at the end of the 21-day period when corticosterone levels were compared. The results of the elevated T test indicated that sleep deprivation did not change the anxiety-like behavior of the animals. When compared with cage or pedestal control groups, sleep deprived rats displayed elevated malondialdehyde levels, and decreased superoxide dismutase and glutathione peroxidase activities together with impaired long-term potentiation maintenance. It can be argued that 21-day SD may impair the maintenance of long-term potentiation evoked in the dentate gyrus, and the balance between oxidant and antioxidant defenses of the hippocampus.
Neuroscience Research 01/2011; 70(1):71-7. · 2.20 Impact Factor
[show abstract][hide abstract] ABSTRACT: In numerous investigations the P300-component of the event related potential has proved a valid indicator of memory activities. The present study explores the amplitude and latency of the components of event-related potential regarding short-term memory task. Event related potentials, elicited by auditory stimuli, were recorded in 40 healthy subjects. For evaluating short term memory capacity of a subject, software in Delphi for Windows language was written. Algorithm of the software was the presentation of randomly selected four different digits for 4 seconds, removing it and waiting for subject's response, adding one digit, if response was true, otherwise decreased by one. After 20 trials, mean of recall time for true answers was computed. The subjects with high recall time showed prolonged latency of P300. A positive correlation was found between P300 latency and recall time. No correlation was found between N1, P2 and N2 latency or amplitude and recall time. These results suggest that memory problems are well correlated with the abnormalities of P300.
International Journal of Neuroscience 12/2000; 105(1-4):77-85. · 1.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: The present study obtained saccadic eye movements from 25 right-handed normal subjects (aged 18-35 yr, mean 22.4 yr) to examine the effects of saccade direction on saccadic parameters (latency, duration and average velocity). Binocular saccadic eye movements were recorded with a direct-current electrooculographic system, and analysis was performed on a laboratory digital computer. The LED target positions were randomly selected 10, 15, 20, 25 and 30 degrees to the left or right of the fixation points. In general, the mean values of the saccadic parameters over large saccade angles were in agreement with those previously reported. There were no significant differences between saccades directed to the right and to the left.
Journal of basic and clinical physiology and pharmacology 02/1999; 10(1):73-7.
[show abstract][hide abstract] ABSTRACT: Reversal of light-dark cycle was used to investigate the effect of the circadian changes on skin conductance, a tonic electrodermal activity parameter, in rats. Rats were adapted for 3 wk. to one of two lighting programs. The animals on the normal cycle were illuminated from 08.00-20.00; on the reverse cycle, from 20.00-08.00. Although during Week 1 to Week 3, skin conductance increased gradually in both groups, this increase was more dramatic in rats adapted to light from 20.00 to 08.00 than in the other group. When the animals on the reverse cycle were readjusted to a normal circadian cycle for 3 weeks, skin conductance decreased gradually to initial values. At Weeks 1, 2, 3, and 6, skin conductance was significantly higher in rats on the reverse light-dark cycle than in those on the normal cycle. The present data suggest that changes in normal light-dark conditions affect skin conductance in rats.
Perceptual and Motor Skills 01/1999; 87(3 Pt 2):1267-74. · 0.49 Impact Factor