Figure 3

Roles of plastic inhibitory feedback to the distal dendritic compartment. (a) Inhibitory feedback model is schematically illustrated. Inhibitory interneurons project to both somatic and dendritic compartments. (b) In this simulation setting, two pyramidal neurons projected to an inhibitory neuron and received inhibitory feedback at the somatic and dendritic compartments. In addition, pyramidal neurons received common somatic inputs from excitatory cell group C and mixed dendritic inputs from two mutually-uncorrelated excitatory cell groups A and B. The activity of cell group C was correlated with the activities of cell groups A and B with equal magnitudes. (c,d) Time evolution of synaptic weights on the dendritic compartments of the two cells with (c) or without (d) dendritic inhibition. The means (lines) and standard deviations (shaded areas) of synaptic weights are shown. (e) A single pyramidal neuron with inhibition fed back onto its dendrite received somatic inputs from a cell group C and dendritic inputs from two cell groups A and B. Activities of input neurons in groups A and B were initially uncorrelated within each group and with other groups. At time 300 sec, correlations were introduced within group A and between groups A and C. At time 600 sec, neurons in group A returned to an uncorrelated state, but neurons in group B became correlated within the group and with group C. (f,g) Time evolution of excitatory synaptic weights on the dendritic compartment with (f) or without (g) dendritic inhibition. (h) Time evolution of inhibitory synaptic weights on the dendritic compartments is displayed.