Impaired Initiation But Not Execution of Contralesional Saccades in Hemispatial Neglect
Patients with unilateral neglect are impaired at making saccades to contralesional targets. Whether this problem arises from a deficit in perception, in planning the saccade or in executing the eye movement or some combination thereof remains unclear. We measured several variables related to the ini...
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| Format: | Article |
| Language: | English |
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Wiley
2002-01-01
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| Series: | Behavioural Neurology |
| Online Access: | http://dx.doi.org/10.1155/2002/253201 |
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| _version_ | 1832560847968272384 |
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| author | Marlene Behrmann Thea Ghiselli-Crippa Ilaria Dimatteo |
| author_facet | Marlene Behrmann Thea Ghiselli-Crippa Ilaria Dimatteo |
| author_sort | Marlene Behrmann |
| collection | DOAJ |
| description | Patients with unilateral neglect are impaired at making saccades to contralesional targets. Whether this problem arises from a deficit in perception, in planning the saccade or in executing the eye movement or some combination thereof remains unclear. We measured several variables related to the initiation and execution of saccades in an experiment which crossed two factors: target side (left, right) and direction of saccade (leftwards, rightwards). Relative to control subjects, patients with left-sided neglect were impaired in planning but not executing the contralesional saccade; while the latency to move their eyes following the onset of the target was increased, the duration and velocity to reach the target were normal. In addition, there were also no directional differences for saccades that were hypometric or inaccurate in the patients, further ruling out an execution impairment. Interestingly, this directional initiation deficit was exaggerated for leftward saccades to left targets, compared with all other conditions. We suggest that the disadvantage for contralesional saccades in neglect patients is attributable to a deficit not only in perceiving contralateral targets but also in planning leftward saccades. Once the saccade is initiated, however, execution apparently proceeds unimpaired. |
| format | Article |
| id | doaj-art-fced6d1ba8a641df8f6d6a4222cfa9da |
| institution | Kabale University |
| issn | 0953-4180 1875-8584 |
| language | English |
| publishDate | 2002-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Behavioural Neurology |
| spelling | doaj-art-fced6d1ba8a641df8f6d6a4222cfa9da2025-02-03T01:26:39ZengWileyBehavioural Neurology0953-41801875-85842002-01-01131-2396010.1155/2002/253201Impaired Initiation But Not Execution of Contralesional Saccades in Hemispatial NeglectMarlene Behrmann0Thea Ghiselli-Crippa1Ilaria Dimatteo2Department of Psychology, Carnegie Mellon University, PA, USADepartment of Information Science, University of Pittsburgh, PA, USADepartment of Statistics, Carnegie Mellon University, PA, USAPatients with unilateral neglect are impaired at making saccades to contralesional targets. Whether this problem arises from a deficit in perception, in planning the saccade or in executing the eye movement or some combination thereof remains unclear. We measured several variables related to the initiation and execution of saccades in an experiment which crossed two factors: target side (left, right) and direction of saccade (leftwards, rightwards). Relative to control subjects, patients with left-sided neglect were impaired in planning but not executing the contralesional saccade; while the latency to move their eyes following the onset of the target was increased, the duration and velocity to reach the target were normal. In addition, there were also no directional differences for saccades that were hypometric or inaccurate in the patients, further ruling out an execution impairment. Interestingly, this directional initiation deficit was exaggerated for leftward saccades to left targets, compared with all other conditions. We suggest that the disadvantage for contralesional saccades in neglect patients is attributable to a deficit not only in perceiving contralateral targets but also in planning leftward saccades. Once the saccade is initiated, however, execution apparently proceeds unimpaired.http://dx.doi.org/10.1155/2002/253201 |
| spellingShingle | Marlene Behrmann Thea Ghiselli-Crippa Ilaria Dimatteo Impaired Initiation But Not Execution of Contralesional Saccades in Hemispatial Neglect Behavioural Neurology |
| title | Impaired Initiation But Not Execution of Contralesional Saccades in Hemispatial Neglect |
| title_full | Impaired Initiation But Not Execution of Contralesional Saccades in Hemispatial Neglect |
| title_fullStr | Impaired Initiation But Not Execution of Contralesional Saccades in Hemispatial Neglect |
| title_full_unstemmed | Impaired Initiation But Not Execution of Contralesional Saccades in Hemispatial Neglect |
| title_short | Impaired Initiation But Not Execution of Contralesional Saccades in Hemispatial Neglect |
| title_sort | impaired initiation but not execution of contralesional saccades in hemispatial neglect |
| url | http://dx.doi.org/10.1155/2002/253201 |
| work_keys_str_mv | AT marlenebehrmann impairedinitiationbutnotexecutionofcontralesionalsaccadesinhemispatialneglect AT theaghisellicrippa impairedinitiationbutnotexecutionofcontralesionalsaccadesinhemispatialneglect AT ilariadimatteo impairedinitiationbutnotexecutionofcontralesionalsaccadesinhemispatialneglect |