Response correlation maps of neurons in the mammalian olfactory bulb

To define the relationship between glomerular activation patterns and neuronal olfactory responses in the main olfactory bulb, intracellular recordings were combined with optical imaging of intrinsic signals. Response correlation maps (RCMs) were constructed by correlating the fluctuations in membrane potential and firing rate during odorant presentations with patterns of glomerular activation. The RCMs indicated that mitral/tufted cells were excited by activation of a focal region surrounding their principal glomerulus and generally inhibited by activation of more distant regions. However, the structure of the RCMs and the relative contribution of excitatory and inhibitory glomerular input evolved and even changed sign during and after odorant application. These data suggest a dynamic center-surround organization of mitral/tufted cell receptive fields.