Concussion. Acceleration limits causing concussion.
Among the many features common to all species of the animal kingdom is the transient loss of function of the nervous system as the result of a jarring blow, a phenomenon known as concussion. Understanding of concussion has been hampered by the lack of a uniform definition, with many authors including cases with gross, irreversible changes. The phenomenon occurs only with a blow that significantly accelerates and thus is best defined as "a transient disturbance of neuronal function as a result of acceleration." There must be a threshold beneath which no loss of function occurs and a ceiling beyond which changes are not reversible. Experiments with nonanesthetized frogs revealed that at 33 g only the occasional frog would be stunned. From 50 to 230 g, consciousness was always lost but rapidly regained and retained, while beyond, the loss was not always reversible. The time of functional loss was increasingly proportional to acceleration.
Parkinson
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Department of Anatomy, University of Manitoba, Winnipeg, Canada.
Jell
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D000054:Acceleration / Q000009:adverse effects*; D000818:Animals; D001924:Brain Concussion / Q000209:etiology* / Q000503:physiopathology; D003128:Coma / Q000209:etiology / Q000503:physiopathology; D004195:Disease Models, Animal; D006112:Gravitation; D006257:Head / Q000503:physiopathology; D011894:Rana pipiens; D009626:Terminology as Topic; D013997:Time Factors