{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T22:10:01Z","timestamp":1792707001187,"version":"4.5.0"},"reference-count":46,"publisher":"Maximum Academic Press","issue":"3","license":[{"start":{"date-parts":[[2009,5,1]],"date-time":"2009-05-01T00:00:00Z","timestamp":1241136000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":["journals.cambridge.org"],"crossmark-restriction":true},"short-container-title":["Vis Neurosci"],"published-print":{"date-parts":[[2009,5]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>The pond turtle (<jats:italic>Trachemys scripta elegans<\/jats:italic>) exhibits a notably sluggish pupillary light reflex (PLR), with pupil constriction developing over several minutes following light onset. In the present study, we examined the dynamics of the efferent branch of the reflex <jats:italic>in vitro<\/jats:italic> using preparations consisting of either the isolated head or the enucleated eye. Stimulation of the oculomotor nerve (nIII) using 100-Hz current trains resulted in a maximal pupil constriction of 17.4% compared to 27.1% observed in the intact animal in response to light. When current amplitude was systematically increased from 1 to 400 <jats:italic>\u03bc<\/jats:italic>A, mean response latency decreased from 64 to 45 ms, but this change was not statistically significant. Hill equations fitted to these responses indicated a current threshold of 3.8 <jats:italic>\u03bc<\/jats:italic>A. Stimulation using single pulses evoked a smaller constriction (3.8%) with response latencies and threshold similar to that obtained using train stimulation. The response evoked by postganglionic stimulation of the ciliary nerve using 100-Hz trains was largely indistinguishable from that of train stimulation of nIII. However, application of single-pulse stimulation postganglionically resulted in smaller pupil constriction at all current levels relative to that of nIII stimulation, suggesting that there is amplification of efferent drive at the ganglion. Time constants for constrictions ranged from 88 to 154 ms with relaxations occurring more slowly at 174\u2013361 ms. These values for timing from <jats:italic>in vitro<\/jats:italic> are much faster than the time constant 1.66 min obtained for the light response in the intact animal. The rapid dynamics of pupil constriction observed here suggest that the slow PLR of the turtle observed <jats:italic>in vivo<\/jats:italic> is not due to limitations of the efferent pathway. Rather, the sluggish response probably results from photoreceptive mechanisms or central processing.<\/jats:p>","DOI":"10.1017\/s0952523809090099","type":"journal-article","created":{"date-parts":[[2009,6,15]],"date-time":"2009-06-15T09:03:26Z","timestamp":1245056606000},"page":"309-318","update-policy":"https:\/\/doi.org\/10.1017\/policypage","source":"Crossref","is-referenced-by-count":9,"title":["Pupil constriction evoked <i>in vitro<\/i> by stimulation of the oculomotor nerve in the turtle (<i>Trachemys scripta elegans<\/i>)"],"prefix":"10.48130","volume":"26","author":[{"suffix":"JR","given":"JAMES R.","family":"DEARWORTH","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J.E.","family":"BRENNER","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J.F.","family":"BLAUM","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"T.E.","family":"LITTLEFIELD","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D.A.","family":"FINK","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J.M.","family":"ROMANO","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M.S.","family":"JONES","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"27968","published-online":{"date-parts":[[2009,5,1]]},"reference":[{"key":"S0952523809090099_ref46","first-page":"220","article-title":"Effect of oculomotor nerve stimulation on outflow facility and pupil diameter in a monkey (cercopithecus ethiops)","volume":"9","author":"T\u00f6rnqvist","year":"1970","journal-title":"Investigative Ophthalmology"},{"key":"S0952523809090099_ref42","doi-asserted-by":"crossref","first-page":"1165","DOI":"10.1152\/ajplegacy.1966.210.5.1165","article-title":"Electrical stimulation of the isolated cat iris","volume":"210","author":"Schaeppi","year":"1966","journal-title":"The American Journal of Physiology"},{"key":"S0952523809090099_ref31","doi-asserted-by":"publisher","DOI":"10.1016\/B978-012370880-9.00282-6"},{"key":"S0952523809090099_ref39","doi-asserted-by":"crossref","first-page":"600","DOI":"10.1523\/JNEUROSCI.20-02-00600.2000","article-title":"A novel human opsin in the inner retina","volume":"20","author":"Provencio","year":"2000","journal-title":"Journal of Neuroscience"},{"key":"S0952523809090099_ref16","doi-asserted-by":"publisher","DOI":"10.1016\/0006-8993(78)90534-6"},{"key":"S0952523809090099_ref41","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1152\/ajplegacy.1964.206.2.255","article-title":"Reaction of isolated pig iris sphincter to electrical stimulation and acetylcholine","volume":"206","author":"Schaeppi","year":"1964","journal-title":"The American Journal of Physiology"},{"key":"S0952523809090099_ref26","doi-asserted-by":"publisher","DOI":"10.1001\/archneurpsyc.1950.02310270002001"},{"key":"S0952523809090099_ref30","first-page":"127","volume-title":"Turtles: Perspective and Research","author":"Maxwell","year":"1979"},{"key":"S0952523809090099_ref3","doi-asserted-by":"publisher","DOI":"10.1016\/0042-6989(69)90047-9"},{"key":"S0952523809090099_ref19","doi-asserted-by":"publisher","DOI":"10.1152\/jn.01205.2007"},{"key":"S0952523809090099_ref44","doi-asserted-by":"publisher","DOI":"10.1016\/j.cbpa.2006.03.019"},{"key":"S0952523809090099_ref34","doi-asserted-by":"publisher","DOI":"10.1016\/0014-4886(76)90201-6"},{"key":"S0952523809090099_ref29","doi-asserted-by":"publisher","DOI":"10.1242\/jeb.01056"},{"key":"S0952523809090099_ref8","doi-asserted-by":"publisher","DOI":"10.1038\/283860a0"},{"key":"S0952523809090099_ref27","doi-asserted-by":"publisher","DOI":"10.1001\/archneurpsyc.1950.02310270030002"},{"key":"S0952523809090099_ref13","doi-asserted-by":"publisher","DOI":"10.1016\/j.visres.2006.12.015"},{"key":"S0952523809090099_ref18","first-page":"565","article-title":"Extraocular muscle action from brain stimulation in the macaque","volume":"1","author":"Jampel","year":"1962","journal-title":"Investigative Ophthalmology"},{"key":"S0952523809090099_ref9","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-4695(199708)33:2<99::AID-NEU1>3.0.CO;2-7"},{"key":"S0952523809090099_ref4","doi-asserted-by":"publisher","DOI":"10.1007\/s00221-006-0649-6"},{"key":"S0952523809090099_ref23","doi-asserted-by":"publisher","DOI":"10.1046\/j.1463-5224.2002.00231.x"},{"key":"S0952523809090099_ref25","volume-title":"The Pupil\u2014Anatomy, Physiology, and Clinical Applications. 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