Plateau potentials
{{Short description|Type of electrical behavior seen in neurons}}
Plateau potentials, caused by persistent inward currents (PICs), are a type of electrical behavior seen in neurons.
Spinal cord
Plateau potentials are of particular importance to spinal cord motor systems.{{cite journal|last1=Svirskis|first1=G|last2=Gutman|first2=A|last3=Hounsgaard|first3=J|title=Electrotonic structure of motoneurons in the spinal cord of the turtle: inferences for the mechanisms of bistability.|journal=Journal of Neurophysiology|date=January 2001|volume=85|issue=1|pages=391–8|pmid=11152739|doi=10.1152/jn.2001.85.1.391}} PICs are set up by the influence of descending monoaminergic reticulospinal pathways. Metabotropic neurotransmitters, via monoaminergic input such as 5-HT and norepinephrine, modulate the activity of dendritic L-type Calcium channels that allow a sustained, positive, inward current into the cell. This leads to a lasting depolarisation. In this state, the cell fires action potentials independent of synaptic input. The PICs can be turned off via the activation of high-frequency inhibitory input at which point the cell returns to a resting state.
Olfactory bulb
Periglomerular cells, inhibitory interneurons that surround and innervate olfactory glomeruli, have also been shown to exhibit plateau potentials.{{cite journal|last1=Masurkar|first1=AV|last2=Chen|first2=WR|title=Potassium currents of olfactory bulb juxtaglomerular cells: characterization, simulation, and implications for plateau potential firing.|journal=Neuroscience|date=29 September 2011|volume=192|pages=247–62|doi=10.1016/j.neuroscience.2011.06.012|pmid=21704678|pmc=3170655}}{{cite journal|last1=Zhou|first1=Z|last2=Xiong|first2=W|last3=Masurkar|first3=AV|last4=Chen|first4=WR|last5=Shepherd|first5=GM|title=Dendritic calcium plateau potentials modulate input-output properties of juxtaglomerular cells in the rat olfactory bulb.|journal=Journal of Neurophysiology|date=November 2006|volume=96|issue=5|pages=2354–63|doi=10.1152/jn.00003.2006|pmid=16855116|s2cid=11512553}}
Cortex and hippocampus
Plateau potentials are also seen in the cortical,{{cite journal|last1=Major|first1=G|last2=Polsky|first2=A|last3=Denk|first3=W|last4=Schiller|first4=J|last5=Tank|first5=DW|title=Spatiotemporally graded NMDA spike/plateau potentials in basal dendrites of neocortical pyramidal neurons.|journal=Journal of Neurophysiology|date=May 2008|volume=99|issue=5|pages=2584–601|doi=10.1152/jn.00011.2008|pmid=18337370|hdl=11858/00-001M-0000-002C-07A3-4|hdl-access=free}}{{cite journal|last1=Milojkovic|first1=BA|last2=Radojicic|first2=MS|last3=Antic|first3=SD|title=A strict correlation between dendritic and somatic plateau depolarizations in the rat prefrontal cortex pyramidal neurons.|journal=The Journal of Neuroscience |date=13 April 2005|volume=25|issue=15|pages=3940–51|doi=10.1523/JNEUROSCI.5314-04.2005|pmid=15829646|pmc=5643048}} and hippocampal pyramidal{{cite journal|last1=Suzuki|first1=T|last2=Kodama|first2=S|last3=Hoshino|first3=C|last4=Izumi|first4=T|last5=Miyakawa|first5=H|title=A plateau potential mediated by the activation of extrasynaptic NMDA receptors in rat hippocampal CA1 pyramidal neurons.|journal=The European Journal of Neuroscience|date=August 2008|volume=28|issue=3|pages=521–34|doi=10.1111/j.1460-9568.2008.06324.x|pmid=18702724}} neurons. Using iontophoretic, or two-photon glutamate uncaging experiments, it has been discovered that these plateau potentials include activities of voltage dependent calcium channels and NMDA receptors.