René Descartes René Descartes ( , ; ; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and Modern science, science. Mathematics was paramou ...

(1596–1650) was one of the first to conceive a model of reciprocal innervation (in 1626) as the principle that provides for the control of

agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

and

antagonist An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

s. Reciprocal innervation describes skeletal muscles as existing in antagonistic pairs, with contraction of one muscle producing forces opposite to those generated by contraction of the other. For example, in the human arm, the

triceps The triceps, or triceps brachii (Latin for "three-headed muscle of the arm"), is a large muscle on the ventral, back of the upper limb of many vertebrates. It consists of three parts: the medial, lateral, and long head. All three heads cross the ...

acts to extend the lower arm outward while the

biceps The biceps or biceps brachii (, "two-headed muscle of the arm") is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join to form a single muscle bel ...

acts to flex the lower arm inward. To reach optimum efficiency, contraction of opposing muscles must be inhibited while muscles with the desired action are excited. This reciprocal innervation occurs so that the contraction of a muscle results in the simultaneous relaxation of its corresponding antagonist. A common example of reciprocal innervation, is the effect of the

nociceptive In physiology, nociception , also nocioception; ) is the sensory nervous system's process of encoding noxious stimuli. It deals with a series of events and processes required for an organism to receive a painful stimulus, convert it to a molecular ...

(or nocifensive) reflex, or defensive response to pain, otherwise commonly known as the

withdrawal reflex The withdrawal reflex (nociceptive flexion reflex or flexor withdrawal reflex) is a spinal reflex intended to protect the body from damaging stimuli. The reflex rapidly coordinates the contractions of all the flexor muscles and the relaxations of ...

; a type of involuntary action of the body to remove the body part from the vicinity of an offending object by contracting the appropriate muscles (usually flexor muscles), while relaxing the extensor muscles, allowing smooth movement. The concept of reciprocal innervation as applicable to the

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

is also known as Sherrington's law (after

Charles Scott Sherrington Sir Charles Scott Sherrington (27 November 1857 – 4 March 1952) was a British neurophysiology, neurophysiologist. His experimental research established many aspects of contemporary neuroscience, including the concept of the spinal reflex as a ...

), wherein increased innervation to an extraocular muscle is accompanied by a simultaneous decrease in innervation to its specific antagonist, such as the medial rectus and the lateral rectus in the case of an eye looking to one side of the midline. When looking outward or laterally, the lateral rectus of one eye must contract via increased innervation, while its antagonist, the medial rectus of the same eye - shall relax. The converse would occur in the other eye, both eyes demonstrating the law of reciprocal innervation. The significance of Descartes’ Law of Reciprocal Innervation has been additionally highlighted by recent research and applications of

bioengineering Biological engineering or bioengineering is the application of principles of biology and the tools of engineering to create usable, tangible, economically viable products. Biological engineering employs knowledge and expertise from a number ...

concepts, such as optimal control and quantitative models of the motor impulses sent by the brain to control eye motion.

References

Muscular system Ophthalmology Neurophysiology {{Muscle-stub

See also

References