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Activity of most rostral ventromedial medulla neurons reflect EEG/EMG pattern changes

1989; American Physiological Society; Volume: 257; Issue: 6 Linguagem: Inglês

10.1152/ajpregu.1989.257.6.r1496

1522-1490

Dennis A. Grahn, H. Craig Heller,

Neural dynamics and brain function

Studies in lightly anesthetized animals have demonstrated neurons in the rostral ventromedial medulla (RVM) that respond to specific modalities of peripheral stimulation. We initiated this study to investigate putative thermoafferent processing in such RVM neurons. Our results indicate that most RVM neuronal responses are not specific for the applied stimulus but reflect changes in cortical activation. Electroencephalogram/electromyogram (EEG/EMG) and RVM single unit activity was recorded in lightly urethan-anesthetized rats. Five distinct EEG/EMG patterns were observed. Their expression was a function of skin and core temperatures. Pinches and strong thermal manipulations caused a desynchronization of a synchronized EEG pattern and an increase in EMG activity. The activity of 38 of the 51 RVM neurons sampled correlated with changes in EEG/EMG activity. Thirteen neurons were not affected by changes in EEG/EMG activity. One unit responded to temperature manipulations within an EEG/EMG state, suggesting that a small portion of RVM neurons may transmit thermoafferent information.