Show simple item record Sparks, Fraser T. Lehmann, Hugo Hernandez, Khadaryna Sutherland, Robert J. 2017-10-13T22:29:26Z 2017-10-13T22:29:26Z 2011
dc.identifier.citation Sparks, F. T., Lehmann, H., Hernandez, K., & Sutherland, R. J. (2011). Suppression of neurotoxic lesion-induced seizure activity: Evidence for a permanent role for the hippocampus in contextual memory. PLoS ONE, 6(11), e27426. doi:10.1371/journal.pone.0027426 en_US
dc.description Sherpa Romeo green journal; open access en_US
dc.description.abstract Damage to the hippocampus (HPC) using the excitotoxin N-methyl-D-aspartate (NMDA) can cause retrograde amnesia for contextual fear memory. This amnesia is typically attributed to loss of cells in the HPC. However, NMDA is also known to cause intense neuronal discharge (seizure activity) during the hours that follow its injection. These seizures may have detrimental effects on retrieval of memories. Here we evaluate the possibility that retrograde amnesia is due to NMDAinduced seizure activity or cell damage per se. To assess the effects of NMDA induced activity on contextual memory, we developed a lesion technique that utilizes the neurotoxic effects of NMDA while at the same time suppressing possible associated seizure activity. NMDA and tetrodotoxin (TTX), a sodium channel blocker, are simultaneously infused into the rat HPC, resulting in extensive bilateral damage to the HPC. TTX, co-infused with NMDA, suppresses propagation of seizure activity. Rats received pairings of a novel context with foot shock, after which they received NMDA-induced, TTX+NMDAinduced, or no damage to the HPC at a recent (24 hours) or remote (5 weeks) time point. After recovery, the rats were placed into the shock context and freezing was scored as an index of fear memory. Rats with an intact HPC exhibited robust memory for the aversive context at both time points, whereas rats that received NMDA or NMDA+TTX lesions showed a significant reduction in learned fear of equal magnitude at both the recent and remote time points. Therefore, it is unlikely that observed retrograde amnesia in contextual fear conditioning are due to disruption of non-HPC networks by propagated seizure activity. Moreover, the memory deficit observed at both time points offers additional evidence supporting the proposition that the HPC has a continuing role in maintaining contextual memories. en_US
dc.language.iso en_US en_US
dc.publisher Public Library of Science en_US
dc.subject Contextual memory en_US
dc.subject Retrograde amnesia en_US
dc.subject Memory impairments en_US
dc.subject Seizure activity en_US
dc.subject Excitotoxin N-methyl-D-aspartate en_US
dc.subject NMDA en_US
dc.subject Neurotoxic en_US
dc.subject Lesion en_US
dc.subject.lcsh Hippocampus (Brain)--Research
dc.subject.lcsh Memory--Research
dc.subject.lcsh Amnesia
dc.subject.lcsh Methyl aspartate
dc.subject.lcsh Animal memory
dc.subject.lcsh Rats as laboratory animals
dc.title Suppression of neurotoxic lesion-induced seizure activity: evidence for a permanent role for the hippocampus in contextual memory en_US
dc.type Article en_US
dc.publisher.faculty Arts and Science en_US
dc.publisher.department Department of Neuroscience en_US
dc.description.peer-review Yes en_US
dc.publisher.institution University of Lethbridge en_US
dc.publisher.institution Trent University en_US

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