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Further evidence for selective difficulty of upward eye pursuit in juvenile monkeys: effects of optokinetic stimulation, static roll tilt, and active head movements
| Title: | Further evidence for selective difficulty of upward eye pursuit in juvenile monkeys: effects of optokinetic stimulation, static roll tilt, and active head movements |
| Authors: | Kasahara, Satoshi Browse this author →KAKEN DB | | Akao, Teppei Browse this author | | Fukushima, Junko Browse this author →KAKEN DB | | Kurkin, Sergei Browse this author →KAKEN DB | | Fukushima, Kikuro Browse this author →KAKEN DB |
| Keywords: | smooth-pursuit | | visual background | | directional asymmetry | | roll tilt | | head-free pursuit |
| Issue Date: | May-2006 |
| Publisher: | Springer |
| Journal Title: | Experimental brain research |
| Volume: | 171 |
| Issue: | 3 |
| Start Page: | 306 |
| End Page: | 321 |
| Publisher DOI: | 10.1007/s00221-005-0278-5 |
| PMID: | 16320042 |
| Abstract: | The smooth-pursuit system moves the eyes in space accurately to track slowly moving objects of interest despite visual inputs from the moving background and/or vestibular inputs during head movements. Recently, our laboratory has shown that young primates exhibit asymmetric eye movements during vertical pursuit across a textured background; upward eye velocity gain is reduced. To further understand the nature of this asymmetry, we performed three series of experiments in young monkeys. In Experiment 1, we examined whether this asymmetry was due to an un-compensated downward optokinetic reflex induced by the textured background as it moves across the retina in the opposite direction of the pursuit eye movements. For this, we examined the monkeys’ ability to fixate a stationary spot in space during movement of the textured background and compared it with vertical pursuit across the stationary textured background. We also examined gains of optokinetic eye movements induced by downward motion of the textured background during upward pursuit. In both task conditions, gains of downward eye velocity induced by the textured background were too small to explain reduced upward eye velocity gains. In Experiment 2, we examined whether the frame of reference for low-velocity, upward pursuit was orbital or earth vertical. To test this, we first applied static tilt in the roll plane until the animals were nearly positioned on their side in order to dissociate vertical or horizontal eye movements in the orbit from those in space. Deficits were observed for upward pursuit in the orbit but not in space. In Experiment 3, we tested whether asymmetry was observed during head-free pursuit that requires coordination between eye and head movements. Asymmetry in vertical eye velocity gains was still observed during head-free pursuit although it was not observed in vertical head velocity. These results, taken together, suggest that the asymmetric eye movements during vertical pursuit are specific for upward, primarily eye pursuit in the orbit. |
| Rights: | The original publication is available at www.springerlink.com. |
| Relation: | http://www.springerlink.com |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/11362 |
| Appears in Collections: | 医学院・医学研究院 (Graduate School of Medicine / Faculty of Medicine) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 福島 菊郎
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