Mossy fiber (hippocampus)

In the hippocampus, the mossy fiber pathway consists of unmyelinated axons projecting from granule cells in the dentate gyrus that terminate on modulatory hilar mossy cells[2][3] and in CA3,[4] a region involved in encoding short-term memory.

There is also evidence for co-localization of both GABAergic (inhibitory) and glutamatergic neurotransmitters within mossy fiber terminals.

[14] Mossy fibers form multiple synapses with the elaborate dendritic spines of CA3 pyramidal cells in the stratum lucidum of the hippocampus.

[4][14] The high convergence onto pyramidal cells and divergent projections onto interneurons suggests a primarily modulatory role for the mossy fiber pathway in the hippocampus.

[16] The dentate gyrus receives excitatory projections from neurons in layer II of the entorhinal cortex as well as input from surrounding neuroglia.

[18][19] Axons from the entorhinal cortex synapse primarily on the dendritic spines of outer layer dentate granule cells.

[21] Projections to the dentate hilus are excitatory by nature and oppose the inhibitory effects of interneurons on hilar mossy cells.

[22] In addition, these variations show strong correlations with different types of behavior, mainly, but not exclusively, spatial learning.