Fixed Action Patterns
Fixed Action Patterns - Related Videos
01:23
Fixed Action Patterns
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2026
A fixed action pattern (FAP) is a specific, hard-wired sequence of behaviors that occurs in response to an external stimulus, called a sign stimulus. The behavior is “fixed” because it is essentially unchangeable—proceeding similarly across individuals of a species every time it occurs. Three-Spined Sticklebacks A classic example of a FAP was described in three-spined stickleback fish by Nikolaas Tinbergen in the 1930s. During the breeding season, the male fish develop a red throat and belly...
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Corticospinal Excitability Modulation During Action Observation
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Cited by 22 •
2013
Single-pulse transcranial magnetic stimulation over the primary motor cortex, neuronavigation, and registration of electromyographic activity of hand muscles were used in this study to explore corticospinal excitability while participants were observing action sequences.
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Fixed Volume or Fixed Pressure: A Murine Model of Hemorrhagic Shock
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Cited by 24 •
2011
The Hemorrhagic Shock model has been a reliable and reproducible resource facilitating the identification and understanding of signaling cascades associated with inflammation and end-organ damage after trauma. This article provides a step-by-step description of surgical and mechanical aspects associated with the Hemorrhagic Shock experimental procedure in mice.
01:14
Action Potential
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2025
Neurons communicate by firing action potentials—the electrochemical signal that is propagated along the axon. The signal results in the release of neurotransmitters at axon terminals, thereby transmitting information to the nervous system. An action potential is a specific "all-or-none" change in membrane potential that results in a rapid spike in voltage. Membrane potential in neurons Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
01:41
Action Potentials
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2025
Overview Neurons communicate by firing action potentials—the electrochemical signal that is propagated along the axon. The signal results in the release of neurotransmitters at axon terminals, thereby transmitting information in the nervous system. An action potential is a specific “all-or-none” change in membrane potential that results in a rapid spike in voltage. Membrane Potential in Neurons Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they...
FAQs
A sign stimulus provides the specific environmental cue that activates an animal’s sensory systems. This activation engages an innate releasing mechanism, which then starts the behavioral sequence. The mechanism links a detectable feature of the environment to a species-typical response, allowing biologists to examine how external information interacts with inherited behavioral organization.
Once the innate releasing mechanism has initiated the sequence, the response generally proceeds toward completion rather than depending continuously on the original cue. This relative independence from ongoing stimulation helps distinguish the pattern from a flexible response that changes immediately with environmental conditions. It also makes the sequence useful for studying the organization of inherited behavior.
Inherited factors provide the behavioral organization associated with a species, while environmental cues determine when that organization is activated. The interaction is therefore not a simple choice between genes and surroundings. Studying the relevant stimulus and the resulting sequence helps biologists investigate how behavior reflects adaptation and natural selection under ecological challenges.
Biologists can compare whether a behavior appears as a species-typical sequence in response to a particular sign stimulus, rather than emerging only after experience or practice. Observing the triggering cue, the activation process, and the sequence’s relative rigidity provides evidence about inherited organization. This approach helps separate behavioral programs from behaviors shaped primarily through learning.
They examine the environmental cue, the sensory detection of that cue, the point at which the response begins, and whether the sequence continues after the cue is removed. Researchers can also record the form and order of actions, using examples such as nest-building, courtship displays, or defensive movements to characterize species-typical behavior.
These patterns give biologists a way to connect observable behavior with inherited traits, sensory signals, and ecological conditions. Their study supports comparisons among species and helps explain responses such as building nests, displaying during courtship, or defending against threats. More broadly, they provide context for investigating adaptation, natural selection, and the biological basis of behavior.