Cortical Interneuron (general)

Function

GABAergic. Shape the timing and gain of cortical excitation: fast-spiking parvalbumin-positive (PV) cells generate gamma oscillations and enforce precise spike timing; somatostatin-positive (SST) Martinotti cells inhibit dendrites and control gain; vasoactive intestinal peptide-positive (VIP) interneurons disinhibit pyramidal cells by inhibiting SST cells.

Morphology

Heterogeneous by design, basket cells target pyramidal somata with 'basket' terminals; chandelier cells target the axon initial segment with cartridge-like synapses; Martinotti cells ascend to layer I and inhibit distal dendritic tufts; bipolar cells sit vertically and target other interneurons.

Specification

• Neurotransmitter: GABA
• Co-transmitters: Subtype-dependent neuropeptides (e.g. VIP, SST, NPY, CCK)
• Receptors: AMPA; NMDA
• Location: Cerebral cortex, across all areas and layers (II-VI), with subtype-specific laminar preferences. (Hippocampus, striatum, and cerebellum have their own distinct interneuron classes; this profile is the cortical interneuron.)
• Projections: Local pyramidal cells
• Firing: Fast-spiking; Regular-spiking
• Markers: GAD1/GAD2; SLC32A1/VGAT; PVALB; SST; VIP; HTR3A (LAMP5/RELN for some human classes)
• Developmental origin: Ganglionic eminences (MGE/CGE)
• Disease: PV interneuron dysfunction is implicated in schizophrenia and is a leading hypothesis for the gamma-oscillation deficits and cognitive symptoms of the disorder.
• Cell Ontology: CL:0000099

References

1. Tremblay R, Lee S, & Rudy B (2016). GABAergic Interneurons in the Neocortex: From Cellular Properties to Circuits.. Neuron 91: 260–292 PMID 27477017
2. Lewis DA, Curley AA, Glausier JR, & Volk DW (2011). Cortical parvalbumin interneurons and cognitive dysfunction in schizophrenia.. Trends Neurosci 35: 57–67 PMID 22154068