Dendrodendritic synapses in the cat reticularis thalami nucleus: a structural basis for thalamic spindle synchronization.

Dendrodendritic synapses have been found between the dendrites of reticularis thalami neurons. These synapses were symmetric and the presynaptic element contained pleomorphic vesicles. A few cases of reciprocal dendrodendritic synapses were also observed. Given the morphological features of the synapses and the well-established GABAergic nature of reticularis neurons it is concluded that reticularis cell dendrites form a local inhibitory network. The functional implications of this type of organization for the synchronization of spindle oscillations are discussed and a new hypothesis is proposed.