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Contractile properties of the lateral rectus in starlings and house sparrows using supramaximal electrical stimulation
Author(s) -
Allawzi Ayed Mamdouh,
Grelle Eve,
Moore Bret,
FernándezJuricic Esteban,
Pelaez Nancy
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1051.31
Subject(s) - isometric exercise , extraocular muscles , contraction (grammar) , anatomy , eye muscle , stimulation , eye movement , force transducer , muscle contraction , biology , physics , neuroscience , endocrinology , physiology , acoustics
Studies show that the degree of eye movement varies between different bird species. This is important from an evolutionary perspective, because species with a high degree of eye movement can substantially change the configuration of their visual fields, and consequently their visual coverage. However, little has been done to study the role that extraocular muscles play in bird eye movement. It was hypothesized that species with finer control of eyes would exhibit faster development of force, shorter contraction times, and muscle contractile adaptability. The left eye of every bird was connected to a force transducer to measure isometric force development of the lateral rectus muscle in response to supramaximal stimulation at 20 volts with 100 Hz frequency. House sparrows had slower rates of contractile force development and longer contractile times, while starlings exhibited faster contractions and shorter contraction times. Standardized length‐tension curve of the two species displayed an ability to contract equally well at a range of lengths. These results seem consistent with starlings fine control of eye movements in contrast to house sparrows.