Considerable research has been carried out to establish a rodent model for the
study of human memory, yet functional similarities between the species remain up for
debate. The hippocampus, a region deep within the medial temporal lobe of the
mammalian CNS, is critical for long-term episodic memory. Projections from the medial
entorhinal cortex convey spatial/contextual information, while projections from the
lateral entorhinal cortex convey item/object information to the hippocampus. The
functional significance of these parallel projections to the rodent hippocampus has been
suggested to support spatial processing, while the same projections to the human
hippocampus support spatial and non-spatial memory. Discharging in a location-specific
manner, hippocampal place cells contribute to spatial memory; however, evidence for
neuronal correlates of non-spatial object memory has not been fully defined. The current
experiments were designed to address the following questions, while utilizing
electrophysiology, functional inactivation during a novel behavioral task, and immunohistochemistry. Is the memory for objects hippocampal-dependent, solely due to
the location of the object, or are objects represented within hippocampal activity
independent of location? To tease apart spatial and non-spatial processing by the
hippocampus, the spatial aspects of 3D objects were enhanced by utilizing movement. A
novel discriminatory avoidance task, Knowing Your Enemy, was adapted from an Enemy
Avoidance task to test true object memory in mice. Current findings support the notion
that object-associations acquisition depends upon a specific context. Retrieval of such
object-associations is not context-dependent, yet remains sensitive to temporary
inactivation of the CA1 region of the dorsal hippocampus. The avoidance impairments
observed following hippocampal inactivation were shown to not be a result of reduced
anxiety. Immunohistochemical marker expression suggests that the CA1 region was
highly active during object exposures, yet the hippocampal system responded
differentially to moving and to stationary objects. Recordings of CA1 neurons yielded
non-bursting object-related activity during object exploration, and place cell activity
remained unaffected in the presence of moving objects; supporting independent, yet
simultaneous processing of spatial and non-spatial information within the hippocampus.
Together, the current findings support the notion that the CA1 region of the rodent
hippocampus processes object-related information, independent of spatial information. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
| Identifer | oai:union.ndltd.org:fau.edu/oai:fau.digital.flvc.org:fau_39817 |
| Contributors | Asgeirsdottir, Herborg Nanna (author), Stackman, Robert W. (Thesis advisor), Florida Atlantic University (Degree grantor), Charles E. Schmidt College of Science, Department of Psychology |
| Publisher | Florida Atlantic University |
| Source Sets | Florida Atlantic University |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation, Text |
| Format | 204 p., application/pdf |
| Rights | Copyright © is held by the author, with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder., http://rightsstatements.org/vocab/InC/1.0/ |
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