Neurogliaform cells (NGF) are inhibitory ( GABAergic) interneurons found in the

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

and the

hippocampus The hippocampus (via Latin from Greek , ' seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, ...

. NGF cells represent approximately 10% of the total hippocampal inhibitory interneuron population. In terms of morphology, they are comparatively small and have an unusually high presynaptic bouton density. Almost all NGF neurons express

neuropeptide Y Neuropeptide Y (NPY) is a 36 amino-acid neuropeptide that is involved in various physiological and homeostatic processes in both the central and peripheral nervous systems. NPY has been identified as the most abundant peptide present in the ma ...

(NPY) and are commonly positive for other signalling and non-signalling peptides, including

reelin Reelin, encoded by the ''RELN'' gene, is a large secreted extracellular matrix glycoprotein that helps regulate processes of neuronal migration and positioning in the developing brain by controlling cell–cell interactions. Besides this impor ...

, α-actinin 2,

COUP-TFII COUP-TFII (COUP transcription factor 2), also known as NR2F2 (nuclear receptor subfamily 2, group F, member 2) is a protein that in humans is encoded by the ''NR2F2'' gene. The COUP acronym stands for chicken ovalbumin upstream promoter. Functio ...

, and neuronal nitric oxide synthase (nNOS). However, populations of NGF cells which do not express NPY have been reported in both cortical layer I and the striatum. Developmentally, in the cortex, all NGF cells are derived from caudal ganglionic eminence (CGE) but NGF cells of the hippocampus have their origins within both the CGE and the

medial ganglionic eminence The ganglionic eminence (GE) is a transitory structure in the development of the nervous system that guides cell and axon migration. It is present in the embryonic and fetal stages of neural development found between the thalamus and caudate nuc ...

(MGE). Functionally, NGF cells are GABAergic and their function in the mature brain is inhibition. However, they are suspected to signal more through volume transmission as opposed to the typical

chemical synapse Chemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous syste ...

. One study found that approximately 78% of neurogliaform cell boutons did not form classical synapses and also indicated that their synaptic boutons are at a larger than usual distance from their target dendrites. Taken together, this and other observations has led to the consensus that NGF cells are likely not involved primarily with “point to point” synaptic transmission but release GABA in a target independent, cloud-like manner to generate a non specific form of inhibitory control (volume transmission).

References

{{Reflist Hippocampus (brain) Brain Neurons Cerebral cortex