Types of synapses in the claustrum of the cat

Basing on structure of synaptic vesicles, symmetry of presynaptic and postsynaptic densities, and size of synaptic boutons, various types of synapses were found in the claustrum. Most of the synapses connect axon terminals with dendritic spines or small dendrities. They are usually asymmetrical with evident postsynaptic thickening. To this type, synapses between corticofugal axons, and claustral cells belong. Synapses between the axon terminals and larger dendrites or cell pericarion are much less frequent, 1-10 synaptic boutons adhering to pericarion were found on a single section of the claustral cell. Axoaxonic and crest-synapses also were found.