Martinotti cells are small multipolar neurons with short branching dendrites. They are scattered throughout various layers of the cerebral cortex, sending their axons up to the cortical layer I where they form axonal arborization. The arbors transgress multiple columns in layer I and make contacts with the distal tuft dendrites of pyramidal cells. 
Recent research suggests that Martinotti cells are associated with a cortical dampening mechanism. When the pyramidal neuron, which is the most common type of neuron in the brain, starts getting over excited, Martinotti cells start sending inhibitory signals to the surrounding neurons.
Martinotti cells were fist described in 1888 by Giovanni Martinotti, an Italian physician.
News, press releases
- Rare cell prevents rampant brain activity - on the discovery of potential dampening influence of Martinotti cells.
- Yun Wang, Maria Toledo-Rodriguez, Anirudh Gupta, Caizhi Wu, Gilad Silberberg, Junyi Luo, and Henry Markram(2004) Anatomical, physiological and molecular properties of Martinotti cells in the somatosensory cortex of the juvenile rat. J Physiol.; 561(Pt 1): 65–90. doi: 10.1113/jphysiol.2004.073353. PMID 15331670 Free Full Text
- Gilad Silberberg, Henry Markram(2007) Disynaptic Inhibition between Neocortical Pyramidal Cells Mediated by Martinotti Cells Neuron. 2007 Mar;53(5):735-46 PMID 17329212 abstract