A fundamental question in understanding neuronal computations is
how dendritic events influence the output of the neuron.
Different forms of integration of neighbouring and distributed
synaptic inputs, isolated dendritic spikes and local regulation
of synaptic efficacy suggest that individual dendritic branches
may function as independent computational subunits. In the
present paper, we study how these local computations influence
the output of the neuron. Using a simple cascade model, we
demonstrate that triggering somatic firing by a relatively small
dendritic branch requires the amplification of local events by
dendritic spiking and synaptic plasticity. The moderately
branching dendritic tree of granule cells seems optimal for this
computation since larger dendritic trees favor local plasticity
by isolating dendritic compartments, while reliable detection of
individual dendritic spikes in the soma requires a low branch
number. Finally, we demonstrate that these parallel dendritic
computations could contribute to the generation of multiple
independent place fields of hippocampal granule cells.
