Topographical Disorientation after Ischemic Mini Infarct in the Dorsal Hippocampus: Whispers in Silence
Silent focal ischemic mini infarcts in the brain are thought to cause no clinically overt symptoms. Some populations of hippocampal cells are particularly sensitive to ischemic events, however, rendering hippocampal functions especially vulnerable to ischemia-induced deficits. The present study inve...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2014-08-01
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| Series: | Frontiers in Behavioral Neuroscience |
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| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fnbeh.2014.00261/full |
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| author | Jamshid eFaraji Jamshid eFaraji Nabiollah eSoltanpour Reza eMoeeini Shabnam eRoudaki Nasrin eSoltanpour Ali-Akbar eAbdollahi Gerlinde A.S. Metz |
| author_facet | Jamshid eFaraji Jamshid eFaraji Nabiollah eSoltanpour Reza eMoeeini Shabnam eRoudaki Nasrin eSoltanpour Ali-Akbar eAbdollahi Gerlinde A.S. Metz |
| author_sort | Jamshid eFaraji |
| collection | DOAJ |
| description | Silent focal ischemic mini infarcts in the brain are thought to cause no clinically overt symptoms. Some populations of hippocampal cells are particularly sensitive to ischemic events, however, rendering hippocampal functions especially vulnerable to ischemia-induced deficits. The present study investigated whether an otherwise silent ischemic mini infarct in the hippocampus (HPC) can produce impairments in spatial performance in rats. Spatial performance was assessed in the ziggurat task (ZT) using a 10-trial spatial learning protocol for four days prior to undergoing hippocampal ischemic lesion or sham surgery. Hippocampal silent ischemia was induced by infusion of endothelin-1 (ET-1), a potent vasoconstrictor, into either the dorsal or the ventral hippocampus (dHPC and vHPC). When tested postoperatively in the ZT using a standard testing protocol for eight days, rats with hippocampal lesions exhibited no spatial deficit. Although spatial learning and memory in the ZT were not affected by the ET-1-induced silent ischemia, rats with dHPC stroke showed more returns when navigating the ZT as opposed to the vHPC rats. Comparison of region-specific HPC lesions in the present study indicated that dorsal hippocampal function is critically required for topographic orientation in a complex environment. Topographic disorientation as reflected by enhanced return behaviours may represent one of the earliest predictors of cognitive decline after silent ischemic insult that may be potentially traced with sensitive clinical examination in humans. |
| first_indexed | 2024-04-13T01:44:03Z |
| format | Article |
| id | doaj.art-43bbcf09c2a24d8a8e36a504e21a3b4a |
| institution | Directory Open Access Journal |
| issn | 1662-5153 |
| language | English |
| last_indexed | 2024-04-13T01:44:03Z |
| publishDate | 2014-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Behavioral Neuroscience |
| spelling | doaj.art-43bbcf09c2a24d8a8e36a504e21a3b4a2022-12-22T03:08:05ZengFrontiers Media S.A.Frontiers in Behavioral Neuroscience1662-51532014-08-01810.3389/fnbeh.2014.0026196802Topographical Disorientation after Ischemic Mini Infarct in the Dorsal Hippocampus: Whispers in SilenceJamshid eFaraji0Jamshid eFaraji1Nabiollah eSoltanpour2Reza eMoeeini3Shabnam eRoudaki4Nasrin eSoltanpour5Ali-Akbar eAbdollahi6Gerlinde A.S. Metz7University of LethbridgeGolestan University of Medical SciencesBabol University of Medical SciencesAvicenna Institute of NeuroscienceAvicenna Institute of NeuroscienceUniversity of LethbridgeGolestan University of Medical SciencesUniversity of LethbridgeSilent focal ischemic mini infarcts in the brain are thought to cause no clinically overt symptoms. Some populations of hippocampal cells are particularly sensitive to ischemic events, however, rendering hippocampal functions especially vulnerable to ischemia-induced deficits. The present study investigated whether an otherwise silent ischemic mini infarct in the hippocampus (HPC) can produce impairments in spatial performance in rats. Spatial performance was assessed in the ziggurat task (ZT) using a 10-trial spatial learning protocol for four days prior to undergoing hippocampal ischemic lesion or sham surgery. Hippocampal silent ischemia was induced by infusion of endothelin-1 (ET-1), a potent vasoconstrictor, into either the dorsal or the ventral hippocampus (dHPC and vHPC). When tested postoperatively in the ZT using a standard testing protocol for eight days, rats with hippocampal lesions exhibited no spatial deficit. Although spatial learning and memory in the ZT were not affected by the ET-1-induced silent ischemia, rats with dHPC stroke showed more returns when navigating the ZT as opposed to the vHPC rats. Comparison of region-specific HPC lesions in the present study indicated that dorsal hippocampal function is critically required for topographic orientation in a complex environment. Topographic disorientation as reflected by enhanced return behaviours may represent one of the earliest predictors of cognitive decline after silent ischemic insult that may be potentially traced with sensitive clinical examination in humans.http://journal.frontiersin.org/Journal/10.3389/fnbeh.2014.00261/fullHippocampusspatial navigationpredictive markerspatial performancetopographical disorientationSilent stroke |
| spellingShingle | Jamshid eFaraji Jamshid eFaraji Nabiollah eSoltanpour Reza eMoeeini Shabnam eRoudaki Nasrin eSoltanpour Ali-Akbar eAbdollahi Gerlinde A.S. Metz Topographical Disorientation after Ischemic Mini Infarct in the Dorsal Hippocampus: Whispers in Silence Frontiers in Behavioral Neuroscience Hippocampus spatial navigation predictive marker spatial performance topographical disorientation Silent stroke |
| title | Topographical Disorientation after Ischemic Mini Infarct in the Dorsal Hippocampus: Whispers in Silence |
| title_full | Topographical Disorientation after Ischemic Mini Infarct in the Dorsal Hippocampus: Whispers in Silence |
| title_fullStr | Topographical Disorientation after Ischemic Mini Infarct in the Dorsal Hippocampus: Whispers in Silence |
| title_full_unstemmed | Topographical Disorientation after Ischemic Mini Infarct in the Dorsal Hippocampus: Whispers in Silence |
| title_short | Topographical Disorientation after Ischemic Mini Infarct in the Dorsal Hippocampus: Whispers in Silence |
| title_sort | topographical disorientation after ischemic mini infarct in the dorsal hippocampus whispers in silence |
| topic | Hippocampus spatial navigation predictive marker spatial performance topographical disorientation Silent stroke |
| url | http://journal.frontiersin.org/Journal/10.3389/fnbeh.2014.00261/full |
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