Mu rhythm
Encyclopedia
Mu rhythm is a kind of brain wave
rhythm measured using Electroencephalography
that has a maximal amplitude
of somatosensory cortices
at rest. It is also called arciform rhythm because of the shape of the waveform
s.
of the μ rhythm is believed to reflect the electrical output of the synchronization of large portions of pyramidal neurons of the motor cortex
which control the hand and arm movement when inactive. In 1950 Gastaut
and his coworkers reported desynchronization of these rhythms not only during active movements of their subjects, but also while the subjects observed actions executed by someone else. These results were later confirmed by additional research groups, including a study using subdural electrode
grids in epileptic patients. The latter study showed mu suppression while the patients observed moving body parts in somatic
areas of the cortex that corresponded to the body part moved by the actor. Further studies have shown that the mu rhythms can also be desynchronized by imaging actions and by passively viewing point-light biological motion
. Current research concerning the mu rhythm is concerned with the development of this rhythm in infancy, its possible links to the human mirror neuron
system, and the implications of the sensorimotor origins of this rhythm.
Electroencephalography
Electroencephalography is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain...
rhythm measured using Electroencephalography
Electroencephalography
Electroencephalography is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain...
that has a maximal amplitude
Amplitude
Amplitude is the magnitude of change in the oscillating variable with each oscillation within an oscillating system. For example, sound waves in air are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation...
of somatosensory cortices
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
at rest. It is also called arciform rhythm because of the shape of the waveform
Waveform
Waveform means the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form. In these cases, the term 'waveform' refers to the shape of a graph...
s.
Description
Usually encompassed in the alpha range (8-12Hz), it is strongly suppressed during the performance of contralateral motor acts. ModulationModulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a high-frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted...
of the μ rhythm is believed to reflect the electrical output of the synchronization of large portions of pyramidal neurons of the motor cortex
Motor cortex
Motor cortex is a term that describes regions of the cerebral cortex involved in the planning, control, and execution of voluntary motor functions.-Anatomy of the motor cortex :The motor cortex can be divided into four main parts:...
which control the hand and arm movement when inactive. In 1950 Gastaut
Henri Gastaut
Henri Gastaut was a French neurologist.Henri Gastaut was educated in neurology and neuroanatomy at the University of Marseille, graduating M.D. in 1945. In 1953 he became head of the neurobiological laboratories. He was appointed professor of anatomical pathology in 1954 and director of the...
and his coworkers reported desynchronization of these rhythms not only during active movements of their subjects, but also while the subjects observed actions executed by someone else. These results were later confirmed by additional research groups, including a study using subdural electrode
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
grids in epileptic patients. The latter study showed mu suppression while the patients observed moving body parts in somatic
Somatic
The term somatic means 'of the body',, relating to the body. In medicine, somatic illness is bodily, not mental, illness. The term is often used in biology to refer to the cells of the body in contrast to the germ line cells which usually give rise to the gametes...
areas of the cortex that corresponded to the body part moved by the actor. Further studies have shown that the mu rhythms can also be desynchronized by imaging actions and by passively viewing point-light biological motion
Biological motion
Biological motion is a term used by social and cognitive neuroscientists to refer to the unique visual phenomenon of a moving, animate object. Often, the stimuli used in biological motion experiments are just a few moving dots that reflect the motion of some key joints of the moving organism...
. Current research concerning the mu rhythm is concerned with the development of this rhythm in infancy, its possible links to the human mirror neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
system, and the implications of the sensorimotor origins of this rhythm.