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Showing 2 results for Motaghi

Vahid Sheibani, Sahel Motaghi, Rasool Farazifard, Hossein Joneidi, Mohammad Reza Afarinesh,
Volume 10, Issue 2 (Summer 2006)

Introduction: It is believed that Locus Coeruleus (LC) influences the sensory information processing. However, its role in cortical surround inhibitory mechanism is not understood. In this experiment, using controlled mechanical displacement of whiskers we investigated the effect of phasic electrical stimulation of LC on response of layer V barrel cortical neurons in anesthetized rat. Methods: LC was stimulated 0, 50, 100, 200 and 400ms before principal or adjacent whiskers deflection. For assessing the effect of LC stimulation on inhibitory receptive field of the barrel neurons, adjacent whisker was also deflected 20ms before principal whisker deflection, and LC stimulation was applied 0-400ms before principal whisker displacement. Results: We found that LC stimulation increased the response magnitude of layer V neurons to principal whisker deflection (significance level (p<0.05) at 50-400ms intervals). This increase in response magnitude was observed to adjacent whisker deflection too (significant (p<0.01) at 100ms interval). The response latency of neurons was decreased when LC was stimulated 400ms before principal whisker deflection (p<0.01). LC stimulation did not affect the neuronal response latency to adjacent whisker displacement or spontaneous activity of neurons. Inhibitory effect of adjacent whisker deflection on neuronal response magnitude was increased by LC stimulation when tested when combined whisker displacement. Conclusion: These findings suggest that LC by modulating the neuronal responses enhances the neuronal responsiveness to sensory stimuli and increases their surround inhibition in cortex.
Sahel Motaghi, Mohammad Niknazar, Mohammad Sayyah, Vahab Babapour, Bijan Vosoughi Vahdat, Mohammad Bagher Shamsollahi,
Volume 16, Issue 1 (Spring 2012)

Introduction: Temporal lobe epilepsy (TLE) is the most common and drug resistant epilepsy in adults. Due to behavioral, morphologic and electrographic similarities, pilocarpine model of epilepsy best resembles TLE. This study was aimed at determination of the changes in electroencephalogram (EEG) sub-bands amplitude during focal seizures in the pilocarpine model of epilepsy. Analysis of these changes might help detection of a pre-seizure state before an oncoming seizure. Methods: Rats were treated by scopolamine (1mg/kg, s.c) to prevent cholinergic effects. After 30 min, pilocarpine (380 mg/kg, i.p) was administered to induce status epilepticus (SE) and 2 hours after SE, diazepam (20 mg/kg, i.p) was injected to suppress the seizures. EEG was recorded in the epileptic rats by superficial electrodes. EEG signal in each rat was decomposed to its sub-bands alpha, beta, gamma, theta and delta by Daubechies wavelet transform. The power (square of amplitude) of sub-band during focal seizures was compared with the same sub-band in pre-ictal stage and the percent of changes in each rat was calculated. Results: SE occurred in 65% of the animals and happened 39.4±5.4 min after injection of pilocarpine. Focal and generalized seizures were developed 3.8±0.4 and 7.0±0.5 days after SE, respectively. Although power of EEG and its sub-bands decreased during focal seizures, the changes were not statistically significant. The greatest decrease in power pertained to beta and gamma sub-bands, while alpha and theta sub-bands underwent the least changes. Conclusion: Based on the protocol used in this study, it seems that the power of EEG sub-bands does not change during focal seizures in pilocarpine model of epilepsy.

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