Escape reflex
{{distinguish|Escape response}}
Escape reflex, or escape behavior, is any kind of escape response found in an animal when it is presented with an unwanted stimulus.{{cite APA Dictionary |title=Escape behaviour |shortlink=escape-behavior |access-date=2020-01-31 }} It is a simple reflectory reaction in response to stimuli indicative of danger, that initiates an escape motion of an animal. The escape response has been found to be processed in the telencephalon.{{cite journal |vauthors=Schwarze S, Bleckmann H, Schluessel V |title=Avoidance conditioning in bamboo sharks (Chiloscyllium griseum and C. punctatum): behavioral and neuroanatomical aspects |journal=Journal of Comparative Physiology A: Neuroethology, Sensory, Neural & Behavioral Physiology |volume=199 |issue=10 |pages=843–56 |date=October 2013 |pmid=23958858 |doi=10.1007/s00359-013-0847-1 |s2cid=18977904 }}File:Cockroach escape reflex.jpg Escape reflexes control the seemingly chaotic motion of a cockroach running out from under a foot when one tries to squash it.
File:Escape reflex muscles.jpg
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 receptors in the stimulated body part send signals to the spinal cord along a sensory neuron. Within the spine, a reflex arc switches the signals straight back to the muscles of the arm (effectors) 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 only becomes aware of the response after it has taken place.
Crossed extensor reflex
The crossed extensor reflex is another escape reflex, but it's a type of withdrawal reflex.{{Cite web |url=https://courses.lumenlearning.com/boundless-ap/chapter/reflexes/ |title=Reflexes |work=Boundless Anatomy and Physiology |publisher=courses.lumenlearning.com |access-date=2020-04-27}} 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 For example, stepping on a piece of glass causes the affected leg to be lifted or withdrawn and the unaffected leg to carry the additional burden of weight and maintain postural support.{{cite book |vauthors=Purves D, Augustine GJ, Fitzpatrick D, Katz LC, LaMantia AS, McNamara JO, Williams SM |date=2001 |chapter=Flexion Reflex Pathways |chapter-url= https://www.ncbi.nlm.nih.gov/books/NBK11091/|title=Neuroscience |edition=2nd |location=Sunderland (MA) |publisher= Sinauer Associates}} 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.{{cite journal |vauthors=King CD, Devine DP, Vierck CJ, Rodgers J, Yezierski RP |title=Differential effects of stress on escape and reflex responses to nociceptive thermal stimuli in the rat |journal=Brain Research |volume=987 |issue=2 |pages=214–22 |date=October 2003 |pmid=14499966 |doi=10.1016/S0006-8993(03)03339-0|s2cid=2028959 }} These factors cause delays or weakness in the reflex, and they can even develop into learned helplessness, which has been found in animals and Drosophila flies.{{cite journal |vauthors=Batsching S, Wolf R, Heisenberg M |title=Inescapable Stress Changes Walking Behavior in Flies - Learned Helplessness Revisited |journal=PLOS ONE |volume=11 |issue=11 |pages=e0167066 |date=2016-11-22 |pmid=27875580 |pmc=5119826 |doi=10.1371/journal.pone.0167066 |doi-access=free |bibcode=2016PLoSO..1167066B }} The reflex can also be habituated as seen in the tail-flip escape reflex of crayfish.{{cite journal |vauthors=Krasne FB, Teshiba TM |title=Habituation of an invertebrate escape reflex due to modulation by higher centers rather than local events |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=92 |issue=8 |pages=3362–6 |date=April 1995 |pmid=7724567 |pmc=42166 |doi=10.1073/pnas.92.8.3362 |doi-access=free |bibcode=1995PNAS...92.3362K }} More recent studies have also indicated that, once this crayfish escape response is habituated, it can also be recovered.{{cite journal |vauthors=Stahlman WD, Chan AA, Blumstein DT, Fast CD, Blaisdell AP |title=Auditory stimulation dishabituates anti-predator escape behavior in hermit crabs (Coenobita clypeatus) |journal=Behavioural Processes |volume=88 |issue=1 |pages=7–11 |date=September 2011 |pmid=21756986 |doi=10.1016/j.beproc.2011.06.009 |s2cid=16415525 }} A similar long-term habituation of the C-start escape response has also been studied in the larvae of zebrafish.{{Cite journal|last1=Roberts|first1=Adam C. |last2=Pearce |first2=Kaycey C. |last3=Choe |first3=Ronny C. |last4=Alzagatiti |first4=Joseph B. |last5=Yeung |first5=Anthony K. |last6=Bill |first6=Brent R. |last7=Glanzman |first7=David L. |date=October 2016 |title=Long-term habituation of the C-start escape response in zebrafish larvae |journal=Neurobiology of Learning and Memory |language=en |volume=134 |issue=Pt B |pages=360–368 |doi=10.1016/j.nlm.2016.08.014 |pmc=5031492 |pmid=27555232 }}
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{{cite journal |vauthors=Krasne FB |title=Excitation and habituation of the crayfish escape reflex: the depolarizing response in lateral giant fibres of the isolated abdomen |journal=The Journal of Experimental Biology |volume=50 |issue=1 |pages=29–46 |date=February 1969 |doi=10.1242/jeb.50.1.29 |pmid=4304852 |url=https://jeb.biologists.org/content/50/1/29|url-access=subscription }} and tail-flip reflex{{cite journal |vauthors=Krasne FB, Shamsian A, Kulkarni R |date=January 1997 |title=Altered excitability of the crayfish lateral giant escape reflex during agonistic encounters |journal=The Journal of Neuroscience |volume=17 |issue=2 |pages=709–16 |doi=10.1523/JNEUROSCI.17-02-00709.1997 |pmid=8987792|pmc=6573235 }} in crayfish
- Escape reflex in squid{{Cite journal |last1=Otis |first1=T. S. |last2=Gilly |first2=W. F. |date=1990-04-01 |title=Jet-propelled escape in the squid Loligo opalescens: concerted control by giant and non-giant motor axon pathways. |journal=Proceedings of the National Academy of Sciences |language=en |volume=87 |issue=8 |pages=2911–2915 |doi=10.1073/pnas.87.8.2911 |issn=0027-8424 |pmc=53803 |pmid=2326255|doi-access=free |bibcode=1990PNAS...87.2911O }}
- Dorsal ramp interneuron (DRI) action in Tritonia mollusks{{Cite journal |last1=Frost |first1=W. N. |last2=Hoppe |first2=T. A. |last3=Wang |first3=J. |last4=Tian |first4=L.-M. |date=August 2001 |title=Swim Initiation Neurons in Tritonia diomedea |journal=American Zoologist |language=en |volume=41 |issue=4 |pages=952–961 |doi=10.1093/icb/41.4.952 |issn=0003-1569 |doi-access=free }}{{Cite journal |last1=Frost |first1=W. N. |last2=Katz |first2=P. S. |date=1996-01-09 |title=Single neuron control over a complex motor program. |journal=Proceedings of the National Academy of Sciences |language=en |volume=93 |issue=1 |pages=422–426 |doi=10.1073/pnas.93.1.422 |issn=0027-8424 |pmc=40250 |pmid=8552652|doi-access=free |bibcode=1996PNAS...93..422F }}
- C-start in fish and amphibia{{cite journal |vauthors=Eaton RC, Lee RK, Foreman MB |title=The Mauthner cell and other identified neurons of the brainstem escape network of fish |journal=Progress in Neurobiology |volume=63 |issue=4 |pages=467–85 |date=March 2001 |pmid=11163687 |doi=10.1016/s0301-0082(00)00047-2|s2cid=19271673 }}
- Escape reflex in earthworms{{Cite journal |vauthors=Drewes CD, Vining EP, Zoran MJ |date=1988-11-01 |title=Regeneration of Rapid Escape Reflex Pathways in Earthworms |url=https://academic.oup.com/icb/article/28/4/1077/166348 |journal=Integrative and Comparative Biology |language=en |volume=28 |issue=4 |pages=1077–1089 |doi=10.1093/icb/28.4.1077|doi-access=free }}