A study of synchronization between rats ECoG channels under the anesthesia
In the framework of this work, experimental work was carried out to register ECoG signals in five rodents (rats, males, 9 months old). Two electrodes were inserted invasively over the frontal cortex (AP = 2, L = 2) and the parietal cortex (AP = 2, L = 6). For ECoG registration, an installation based on the 8-channel PowerLab 4/35 system (ADInstruments, Australia) was used. Routine ECoG recording lasted from 2 to 6 hours in the frequency range 0.1–100 Hz with digitization at 400/s/channel.
Signals of the electrical activity of the brain in rodents were recorded during wakefulness, behavioral sleep, and also under the influence of anesthesia. We used chlorahydrate anesthesia (intraperitoneal injection of 4 % chloral hydrate solution at a dose of 325 mg/kg). The marking of the physiological states of the animal was carried out by a neurophysiologist on the basis of a video recording of the experiment.
Further, for the records, the degree of synchronization between the ECoG channels was assessed during wakefulness, behavioral sleep, and under anesthesia. The estimation of the degree of synchronization between the channels was carried out on the basis of calculating the wavelet bicoherence, and the degree of synchronization was estimated in different frequency ranges ( f1 [1–2.5] Hz, f2 [2.5–4.5] Hz, f3 [4.5–6.5] Hz, f4 [5–9] Hz, f5 [9–12] Hz, f6 [12–20] Hz). After that, probability distributions of the degree of synchronization were constructed for each state of the animal.
It was found that the probability distributions for the states of sleep and wakefulness obey a power law, while the distribution for the state when the animal is under the influence of anesthesia has a more complex structure. The greatest differences between the states of wakefulness / sleep and anesthesia are observed in the frequency ranges f3 and f4.
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Saratov State University
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