Fig. 1

Pharmacological analysis of caffeine-assisted oscillation elicited by intra-cortical stimulation in the OSC, focusing on NMDA receptors. An optical recording method was applied. All recordings were performed in caffeine-containing medium. A Optical image acquired at a time latency of 337.0 ms superimposed on the slice illustration. The image includes a high-activity area during one course of oscillation (as shown in B). Note that a high-activity area that emerged repeatedly is considered the origin of oscillatory activities. Thus, the location of oscillatory origin was confirmed to be in the upper layer of the somatosensory cortex, as indicated by the arrow. B Time-course responses of the optical signal obtained at the oscillatory origin (as shown in A). Note that the local area shown in A with the asterisk generated the wave with the asterisk in B. C Time-course response after application of d-AP5 in caffeine-containing medium. Note that the oscillatory phase completely disappeared, but the initial wave did not. The initial slope and peak amplitude of the initial wave were almost the same as those before application of d-AP5. D Time-course response after further application of CNQX in medium containing both caffeine and d-AP5. Note that the initial wave completely disappeared. E The 3 time-course responses shown in B–D are superimposed, and the temporal axis is expanded