Leg mechanics contribute to establishing swing phase trajectories during memory-guided stepping movements in walking cats: a computational analysis
When quadrupeds stop walking after stepping over a barrier with their forelegs, the memory of barrier height and location is retained for many minutes. This memory is subsequently used to guide hind leg movements over the barrier when walking is resumed. The upslope of the initial trajectory of hind...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2015-09-01
|
| Series: | Frontiers in Computational Neuroscience |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fncom.2015.00116/full |
| _version_ | 1828406791858290688 |
|---|---|
| author | Keir Gordon Pearson Naik eArbabzada Rodney eGramlich Masahiro eShinya |
| author_facet | Keir Gordon Pearson Naik eArbabzada Rodney eGramlich Masahiro eShinya |
| author_sort | Keir Gordon Pearson |
| collection | DOAJ |
| description | When quadrupeds stop walking after stepping over a barrier with their forelegs, the memory of barrier height and location is retained for many minutes. This memory is subsequently used to guide hind leg movements over the barrier when walking is resumed. The upslope of the initial trajectory of hind leg paw movements is strongly dependent on the initial location of the paw relative to the barrier. In this study, we have attempted to determine whether mechanical factors contribute significantly in establishing the slope of the paw trajectories by creating a 4-link biomechanical model of a cat hind leg and driving this model with a variety of joint-torque profiles, including average torques for a range on initial paw positions relative to the barrier. Torque profiles for individual steps were determined by an inverse dynamic analysis of leg movements in three normal cats. Our study demonstrates that limb mechanics can contribute to establishing the dependency of trajectory slope on the initial position of the paw relative to the barrier. However, an additional contribution of neuronal motor commands was indicated by the fact that the simulated slopes of paw trajectories were significantly less that the observed slopes. A neuronal contribution to the modification of paw trajectories was also revealed by our observations that both the magnitudes of knee flexor muscle EMG bursts and the initial knee flexion torques depended on initial paw position. Previous studies have shown that a shift in paw position prior to stepping over a barrier changes the paw trajectory to be appropriate for the new paw position. Our data indicate that both mechanical and neuronal factors contribute to this updating process, and that any shift in leg position during the delay period modifies the working memory of barrier location. |
| first_indexed | 2024-12-10T11:16:50Z |
| format | Article |
| id | doaj.art-7fb609da742b4d8bbb67267b61e428e6 |
| institution | Directory Open Access Journal |
| issn | 1662-5188 |
| language | English |
| last_indexed | 2024-12-10T11:16:50Z |
| publishDate | 2015-09-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Computational Neuroscience |
| spelling | doaj.art-7fb609da742b4d8bbb67267b61e428e62022-12-22T01:51:08ZengFrontiers Media S.A.Frontiers in Computational Neuroscience1662-51882015-09-01910.3389/fncom.2015.00116140509Leg mechanics contribute to establishing swing phase trajectories during memory-guided stepping movements in walking cats: a computational analysisKeir Gordon Pearson0Naik eArbabzada1Rodney eGramlich2Masahiro eShinya3University of AlbertaUniversity of AlbertaUniversity of AlbertaUniversity of TokyoWhen quadrupeds stop walking after stepping over a barrier with their forelegs, the memory of barrier height and location is retained for many minutes. This memory is subsequently used to guide hind leg movements over the barrier when walking is resumed. The upslope of the initial trajectory of hind leg paw movements is strongly dependent on the initial location of the paw relative to the barrier. In this study, we have attempted to determine whether mechanical factors contribute significantly in establishing the slope of the paw trajectories by creating a 4-link biomechanical model of a cat hind leg and driving this model with a variety of joint-torque profiles, including average torques for a range on initial paw positions relative to the barrier. Torque profiles for individual steps were determined by an inverse dynamic analysis of leg movements in three normal cats. Our study demonstrates that limb mechanics can contribute to establishing the dependency of trajectory slope on the initial position of the paw relative to the barrier. However, an additional contribution of neuronal motor commands was indicated by the fact that the simulated slopes of paw trajectories were significantly less that the observed slopes. A neuronal contribution to the modification of paw trajectories was also revealed by our observations that both the magnitudes of knee flexor muscle EMG bursts and the initial knee flexion torques depended on initial paw position. Previous studies have shown that a shift in paw position prior to stepping over a barrier changes the paw trajectory to be appropriate for the new paw position. Our data indicate that both mechanical and neuronal factors contribute to this updating process, and that any shift in leg position during the delay period modifies the working memory of barrier location.http://journal.frontiersin.org/Journal/10.3389/fncom.2015.00116/fullWalkingworking memoryobstacle avoidanceleg mechanicsmodel leg movement |
| spellingShingle | Keir Gordon Pearson Naik eArbabzada Rodney eGramlich Masahiro eShinya Leg mechanics contribute to establishing swing phase trajectories during memory-guided stepping movements in walking cats: a computational analysis Frontiers in Computational Neuroscience Walking working memory obstacle avoidance leg mechanics model leg movement |
| title | Leg mechanics contribute to establishing swing phase trajectories during memory-guided stepping movements in walking cats: a computational analysis |
| title_full | Leg mechanics contribute to establishing swing phase trajectories during memory-guided stepping movements in walking cats: a computational analysis |
| title_fullStr | Leg mechanics contribute to establishing swing phase trajectories during memory-guided stepping movements in walking cats: a computational analysis |
| title_full_unstemmed | Leg mechanics contribute to establishing swing phase trajectories during memory-guided stepping movements in walking cats: a computational analysis |
| title_short | Leg mechanics contribute to establishing swing phase trajectories during memory-guided stepping movements in walking cats: a computational analysis |
| title_sort | leg mechanics contribute to establishing swing phase trajectories during memory guided stepping movements in walking cats a computational analysis |
| topic | Walking working memory obstacle avoidance leg mechanics model leg movement |
| url | http://journal.frontiersin.org/Journal/10.3389/fncom.2015.00116/full |
| work_keys_str_mv | AT keirgordonpearson legmechanicscontributetoestablishingswingphasetrajectoriesduringmemoryguidedsteppingmovementsinwalkingcatsacomputationalanalysis AT naikearbabzada legmechanicscontributetoestablishingswingphasetrajectoriesduringmemoryguidedsteppingmovementsinwalkingcatsacomputationalanalysis AT rodneyegramlich legmechanicscontributetoestablishingswingphasetrajectoriesduringmemoryguidedsteppingmovementsinwalkingcatsacomputationalanalysis AT masahiroeshinya legmechanicscontributetoestablishingswingphasetrajectoriesduringmemoryguidedsteppingmovementsinwalkingcatsacomputationalanalysis |