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Background: As we all know, at the molecular level, propofol cortical loop and the whole brain in the hypothalamus plays the role of the GABAA receptor agonist, in network and system level, however, propofol feeling thalamocortical loop information processing, they are still an issue to be examined. Based on this, in the present study, we will have a different depth of propofol anesthesia on the rat ventral medial nucleus (ventral posteromedial nucleus, VPM), primary somatosensory cortex (somatosensory cortex S1), as well as between information processing The observation of the impact of the process system. Method: the experiment, two tungsten electrodes simultaneously VPM and S1 records placed rats in different depth of propofol anesthesia two brain regions spontaneous local field potential (Spontaneous local field potentials sLFPs), beard stimulation induced somatosensory evoked potentials (Somatosensory evoked potentials, SEPs) and stimulate multi-unit activity (Multiple unit activity, MUA). The peripheral stimulation by oscillation contralateral beard completed in each experiment are required to find a can at the same time caused the strongest reaction in the VPM and S1 beard. First recorded 300s of spontaneous activities in each of the depth of anesthesia, then give every 6s time beard stimulus, continued 1000s. The duration of each stimulus to 200ms. Pump of the depth of anesthesia by tail vein injection of propofol rate control. 300s spontaneous field potential event filter as δ in each of the depth of anesthesia, (1-4Hz), θ (4-Hz), α (8-12Hz), β (12-25Hz), and γ (25-60Hz) five bands, while the reaction of SEP stimulus time histogram various depth of anesthesia 1000s beard stimulation induced reaction proceeds. Results: 1. Thalamus VPM, all bands spontaneous field potential activity with anesthetic depth and weakened; S1, α and β band activity weakened with the anesthesia deepened; 2. Deepen propofol anesthesia may extend beards stimulus onset latency SEP S1 induced no significant role in the onset latency of the thalamus VPM SEP; With the deepening of propofol anesthesia, the beard stimulus S1 induced SEP early response peak gradually increased, also will extend the spacing between the peak of early response and delayed reaction, delayed reaction of the peak decreases gradually; 4 the give beard stimulus, the deep anesthesia hypothalamus between VPM and S1 correlation shallow anesthesia significantly increased; 5 in all of the depth of anesthesia, S1 and hypothalamus VPM there are a frequency of 7-14Hz, and the duration of the 2-6s of the spindle oscillation, the two spindle oscillation the spacing between the approximately 2-5s. Meanwhile, in the beard stimulation in the VPM and S1 induced early after the reaction, are follows a stimulation and a length of 2-6s of the shuttle type oscillation. Conclusion: 1. Even under deep anesthesia induced Propofol thalamocortical loop remains peripheral sensory stimuli have a certain degree of reactivity. 2 beard stimulate the cortex evoked the early response amplitude and thalamus correlation between the VPM and S1 with the anesthesia deepened enhanced results suggest that: the thalamocortical loop identifiable firing patterns with anesthesia deepen gradually reduced, leading to the loop decline in information capacity, may be one of the reasons why anesthesia induced loss of consciousness.
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