| Abstract: | In the rat cortical taste area (CTA), we recorded 31 pairs oftaste neurons and seven pairs of taste and non-taste neurons,with single or double electrodes. By using a cross-correlogram(CCG) in a stationary state, we examined the functional interactionbetween neurons of the pairs while activating them by tastestimulation. Though only 14.3% of the taste and non-taste neuronpairs were correlated, 54.8% of the taste neuron pairs showedcorrelated activities, 41.9% of them showing common inputs,including one with an additional excitatory connection. Theremainder (12.9%) showed excitatory connections with a timelag of 1–3 ms. When pairs were recorded using single ordouble electrodes with an intertip distance of <50µmin a dorsoventral direction, a larger fraction had correlatedactivities than when the intertip distance was >50 µm.Whereas pairs of neurons showed correlated activities in areaDI whatever the vertical intertip distance was, most of thepairs having correlated activities in area GI were found within50 µm of the vertical intertip distance. The taste profilesof common inputs to the pair were estimated on the basis ofpeak at time 0 in CCGs for various taste stimuli. The efficacycontribution of the source to target neurons tended to be largerwhen both had the same best stimulus. This tendency held truefor pairs showing excitatory connections. Interlayer excitatoryconnections were also evident. It is concluded that a functionalcolumn with a diameter of 50 µm may present in the CTAin rats, and that information flow is larger between pairs ofneurons with the same best stimulus. Chem. Senses 22: 517–528,1997. |
