The medullary command nucleus (MCN), also called the ''pacemaker nucleus'', is a group of
nerve cells
A neuron (American English), neurone (British English), or nerve cell, is an excitable cell that fires electric signals called action potentials across a neural network in the nervous system. They are located in the nervous system and help to ...
found in the bodies of
weakly electric fish
An electric fish is any fish that can Bioelectrogenesis, generate electric fields, whether to sense things around them, for defence, or to stun prey. Most fish able to produce shocks are also electroreceptive, meaning that they can sense electric ...
. It controls the function of
electrocytes by regulating the frequency of
electrical impulses. Signals originating in the MCN are transmitted to electrocytes, where changes in
ion
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
concentration cause electrical charges to be generated. The nucleus both sends and receives signals, thereby acting as a regulator and central processor for the electro sensors in the fish's body. Inputs into the MCN originate in the mesencephalic precommand nucleus, thalamic dorsal posterior nucleus, and toral ventroposterior nucleus. All of these nuclei have dense projections into the MCN, with the exception of the Toral Ventroposterior nucleus, which contain only a
ventral
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
edge projection.
See also
*
Electric organ
An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has since develop ...
*
Electric fish
An electric fish is any fish that can Bioelectrogenesis, generate electric fields, whether to sense things around them, for defence, or to stun prey. Most fish able to produce shocks are also electroreceptive, meaning that they can sense electric ...
External links
* {{cite web
, url=http://www.jneurosci.org/cgi/content/abstract/23/31/10128?ck=nck
, title=Single-Unit Activity Patterns in Nuclei That Control the Electromotor Command Nucleus during Spontaneous Electric Signal Production in the Mormyrid ''Brienomyrus brachyistius''
, accessdate=2007-11-17
, author=Bruce A. Carlson
, date=2003-11-05
, publisher=The Journal of Neuroscience
Electric fish
Fish nervous system