For the layer of the skin, see stratum lucidum

Stratum lucidum

The stratum lucidum is a thin, clear layer of dead skin cells in the epidermis named for its translucent appearance under a microscope...

.

The stratum lucidum of the hippocampus is also a layer of the hippocampus

Hippocampus

The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...

 between the stratum pyramidale and the stratum radiatum. It is the tract of the mossy fiber projections, both inhibitory and excitatory from the granule cells of the dentate gyrus

Dentate gyrus

The dentate gyrus is part of the hippocampal formation. It is thought to contribute to new memories as well as other functional roles. It is notable as being one of a select few brain structures currently known to have high rates of neurogenesis in adult rats, .The dentate gyrus cells receive...

. One mossy fiber may make up to 37 connections to a single pyramid cell, and innervate around 12 pyramidal cells on top of that. Any given pyramidal cell in the stratum lucidum may get input from as many as 50 granule cells.