Fig. 6: Mixed and single feature selectivity on dendrites depend on presynaptic correlations and distance between soma and dendrite.

a, Membrane potential fluctuations at distal (top) and proximal (bottom) dendrites during ongoing stimulation. Dashed line shows the spiking threshold at the soma. b, NMDA (red) and GABA_A (blue) currents as a function of membrane potential. Spiking threshold and reset are indicated by dotted and dashed lines, respectively. c, Coupling strength between soma and dendritic branch as a function of electrotonic distance fitted to experimental data adapted from ref. ⁴⁵ with permission. d, Schematic of the synaptic organization onto two dendrites (left). In our simulations, both dendrites are connected with the same coupling strength to the soma. The synapses onto one dendrite are plastic for us to assess the effect of co-dependent plasticity, whereas the synapses onto the other dendrite are not plastic to provide background noise mimicking all other dendrites. Each line represents a synapse, with co-active synapses bearing the same color. Examples of clustering of co-active (middle) or independent (right) synapses resulting in single or mixed feature selectivity, respectively, at the level of a single dendrite. Line length indicates synaptic weight in arbitrary units. e, Clustering index as a function of the size of the co-active input group for distal (orange) and proximal (yellow) dendrites with independent (top) and matching (bottom) excitatory and inhibitory inputs. Clustering index is equal to 1 (−1) when only co-active (independent) synapses connected onto a given dendritic branch survived and 0 when all synapses survived (Methods). f, Clustering index (color coded) as a function of the size of co-active input group (x axis) and the distance from the dendrite to the soma (y axis) for independent (top) and matching (bottom) excitatory and inhibitory inputs. Dark green indicates single feature selectivity, whereas brown indicates mixed feature selectivity. Indep., independent; no plast., not plastic; Thr., threshold.