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. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs ...

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 (economi ...

indicative of danger, that initiates an escape motion of an

animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in ...

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

Escape reflexes control the seemingly chaotic motion of a

cockroach Cockroaches (or roaches) are a 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 well-known as ...

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 (e.g. the withdrawal of a hand) in response to a pain stimulus.

Sensory receptor 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 ...

s in the stimulated body part send signals to the spinal cord 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 ...

. 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 Interneurons (also called internuncial neurons, relay neurons, association neurons, connector neurons, intermediate neurons or local circuit neurons) are neurons that connect two brain regions, i.e. not direct motor neurons or sensory neurons. In ...

) 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 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. Duri ...

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 fiber Afferent nerve fibers are the axons (nerve fibers) carried by a sensory nerve that relay sensory information from sensory receptors to regions of the brain. Afferent projections ''arrive'' at a particular brain region. Efferent nerve fibers a ...

s 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'' 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 Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

** Escape reflex in squid ** Dorsal ramp interneuron (DRI) action in ''Tritonia'' mollusks **

C-start The Mauthner cells are a pair of big and easily identifiable neurons (one for each half of the body) located in the rhombomere 4 of the hindbrain in fish and amphibians that are responsible for a very fast escape reflex (in the majority of animals � ...

in fish and amphibia **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. Th ...

References

{{DEFAULTSORT:Escape Reflex Reflexes Behavioral neuroscience

Crossed extensor reflex

Escape reflex arcs

Examples

See also

References