Escape reflex, or escape behavior, is any kind of

escape response Escape response, escape reaction, or escape behavior is a mechanism by which animals avoid potential predation. It consists of a rapid sequence of movements, or lack of movement, that position the animal in such a way that allows it to hide, freeze ...

found in an animal when it is presented with an unwanted stimulus. It is a simple

reflectory reaction In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a Stimulus (physiology), stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous s ...

in response to

stimuli A stimulus is something that causes a physiological response. It may refer to: * Stimulation ** Stimulus (physiology), something external that influences an activity ** Stimulus (psychology), a concept in behaviorism and perception * Stimulus (eco ...

indicative of danger, that initiates an escape motion of an

animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...

. The escape response has been found to be processed in the

telencephalon The cerebrum, telencephalon or endbrain is the largest part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In ...

Escape reflexes control the seemingly chaotic motion of a

cockroach Cockroaches (or roaches) are a Paraphyly, paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are we ...

running out from under a foot when one tries to squash it. Escape reflex muscles

In higher animals, examples of escape reflex include 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 ...

(e.g. the withdrawal of a hand) in response to a pain stimulus. Sensory receptors in the stimulated body part send signals to the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...

along a

sensory neuron Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The cel ...

. Within the spine, a

reflex arc A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons w ...

switches the signals straight back to the muscles of the arm (

effector Effector may refer to: *Effector (biology), a molecule that binds to a protein and thereby alters the activity of that protein * ''Effector'' (album), a music album by the Experimental Techno group Download * ''EFFector'', a publication of the El ...

s) via an intermediate neuron ( interneuron) and then a motor neuron; the muscle contracts. There often is an opposite response of the opposite limb. Because this occurs automatically and independently in the spinal cord, the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...

only becomes aware of the response after it has taken place.

Crossed extensor reflex

The

crossed extensor reflex The crossed extensor reflex or crossed extensor response or crossed extension reflex is a reflex in which the contralateral limb compensates for loss of support when the ipsilateral limb withdraws from painful stimulus in a withdrawal reflex. Dur ...

is another escape reflex, but it's a type of withdrawal reflex. It is a contralateral reflex that allows for the affected limb to have the flexor muscles contract and the extensor muscles to relax while the unaffected limb has the flexor muscles relax and the extensor muscles to contract. For example, stepping on a piece of glass causes the affected leg to be lifted or withdrawn and the unaffected leg to carry the additional burden of weight and maintain postural support. In this example, the afferent nerve fibers are stimulated on the right foot. The nerve fibers travel up to the spinal cord where they cross the midline, go to the left side, and synapse on an interneuron. When the afferent nerve fibers synapse on the interneuron, they can either inhibit or excite an alpha motor neuron on the muscles on side contralateral to the stimulus.

Escape reflex arcs

Escape reflex arcs have a high survival value enabling organisms to take rapid action to avoid potential danger or physical damage. The effectiveness of escape reflexes can be lowered when an organism is experiencing high levels of fatigue and or stress. These factors cause delays or weakness in the reflex, and they can even develop into

learned helplessness Learned helplessness is the behavior exhibited by a subject after enduring repeated aversive stimuli beyond their control. It was initially thought to be caused by the subject's acceptance of their powerlessness, by way of their discontinuing atte ...

, which has been found in animals and ''

Drosophila ''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many speci ...

'' flies. The reflex can also be habituated as seen in the tail-flip escape reflex of crayfish. More recent studies have also indicated that, once this crayfish escape response is habituated, it can also be recovered. A similar long-term habituation of the C-start escape response has also been studied in the larvae of zebrafish. Various animals may have specialized escape reflex arcs.

Examples

*Withdrawal reflexes **Ducking (flexing the neck to protect the head) **Jumping at loud sounds **Withdrawal of a body part when it touches something (e.g., excessively hot or cold) *Other ** Lateral giant escape and tail-flip reflex in crayfish ** Escape reflex in squid ** Dorsal ramp interneuron (DRI) action in ''Tritonia'' mollusks ** C-start in

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

and

amphibia Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arbor ...

**Escape reflex in

earthworm An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. T ...

References

{{DEFAULTSORT:Escape Reflex Reflexes Behavioral neuroscience

Crossed extensor reflex

Escape reflex arcs

Examples

See also

References