Summary
Physical Description
Ecology
Life History & Behaviour
Feeding Behavior
Anatomy & Physiology
Glossary of Gastropod Anatomy
Internal Anatomy
Muscular Foot Strength
Nociceptive Behavior
Evolution & Systematics
Biogeographic Distribution
Conservation & Threats
Human Interaction
Names & Taxonomy
References & Links | Nociceptive behavior is considered to be the capability to react to stimulus caused by a tissue damage or impending danger, either with or without conscious sensation exhibited in the organism (Florey & Stefano, 1991). As pain is a subjective measurement often exemplified in humans, it is difficult to judge whether this sensation conclusively occurs in other organisms. It is currently being studied that molluscs are organisms that respond to noxious stimulation and therefore may have nociceptive capabilities. Under the study of Crook & Walters (2011), it is indicated that there are a few mollusc classes that have shown cognitive capabilities that are consistent with functional states of pain. It is described that the first state of nociception is the activation of sensitive sensory neurons caused by noxious stimuli, but is difficult to define due to that emotion seen in humans is a conscious experience (Sherrington 1906). While invertebrates do not have brain structures used for sensory responses and communication seen in vertebrates, it does not conclude that the organisms are inept from pain and is suggested that invertebrates may have independently evolved neural structures that provide the same function (Crook & Walters, 2011). Gastropods have increased neural complexity and a large behavioral range as a result of a wide range of habitats and specialized sensory organs compared to other mollusc classes, as seen in their large neuronal somota (Chase 2002). Their neural complexity is also seen in studies on their behavior for habituation seen in desensitization from non-harmful stimulus, indicating that these organisms have the capacity for learning (Fig. 1; Razran, 1971). From their increased neural complexity, they are the most studied invertebrates on nociceptive behavior (Crook & Walters, 2011). Air breathing snails, like P. ebeninus, have been studied for nociceptive responses using noxious and tactile stimulus through electricity and physical methods. In snails, this parallel nociceptive behavioral response is exhibited by a response to stimili with thermal stress through the retreat of the anterior region of their extended foot when it becomes in contract with a noxious heated surface (Florey & Stefano, 1991). The study taken by Crook & Walters (2011) demonstrated that while some pulmonates may not be conclusive in whether the organism experiences pain-like sensations, it can be inferred that there may be fundamental components of this sensation present.
Figure 1: An experiment demonstrating snail habituation through the use of non-harmful stimulus from cotton swabs which resulted in decreased time to fully extend its cephalic tentacle exhibiting desensitization behavior. |
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