PIRIFORM CORTEX LATE ACTIVITY REVEALED FUNCTIONAL SPATIAL HETEROGENEITY

OPTICAL signals were recorded in the in vivo rat piriform cortex (PC) in response to olfactory bulb electrical stimulation. Sometimes the ea rly response was followed by a longer latency component with an occurr ence probability of 0.25. In order to compare the early and late activ ity, the ratio between early (disynaptic) and late wave amplitudes was measured at each recording site on the whole PC. Its spatial distribu tion revealed that the relative importance of the late activity was la rger in the most posterior part of the PC whereas the late wave was ra rely observed in the anterior PC. Such a result gave new information o n the functional heterogeneity of the PC.