Figure 6. Blocking cholinergic, noradrenergic and GABAB receptors in the neocortex does not abolish sensory suppression induced by RF stimulation.
A, field potential responses evoked in the neocortex by whisker stimulation. Under control conditions RF stimulation suppresses the evoked response (upper traces). Simultaneous application of scopolamine, hexamethodide, phentolamine, propanolol and CGP35348 enhances the whisker-evoked response, but under these conditions RF stimulation also suppresses the sensory-evoked response (lower traces). Traces are the average of five responses from a representative experiment. B, population data from three experiments in which the drugs mentioned in A were applied. The average for each experiment was calculated from 10-15 control traces and RF traces. RF significantly suppresses whisker-evoked responses during control conditions and after application of the drug combination (*P < 0.0001, t test). Also, application of the drugs significantly enhances the evoked response as compared to control (**P < 0.0001, t test).