Establishing appropriate animal models for the study of human memory is
paramount to the development of memory disorder treatments. Damage to the
hippocampus, a medial temporal lobe brain structure, has been implicated in the memory
loss associated with Alzheimer’s disease and other dementias. In humans, the role of the
hippocampus is largely defined; yet, its role in rodents is much less clear due to
conflicting findings. To investigate these discrepancies, an extensive review of the rodent
literature was conducted, with a focus on studies that used the Novel Object Recognition
(NOR) paradigm for testing. The total amount of time the objects were explored during
training and the delay imposed between training and testing seemed to determine
hippocampal recruitment in rodents. Male C57BL/6J mice were implanted with bilateral
dorsal CA1 guide cannulae to allow for the inactivation of the hippocampus at discrete
time points in the task. The results suggest that the rodent hippocampus is crucial to the
encoding, consolidation and retrieval of object memory. Next, it was determined that there is a delay-dependent involvement of the hippocampus in object memory, implying
that other structures may be supporting the memory prior to the recruitment of
hippocampus. In addition, when the context memory and object memory could be further
dissociated, by altering the task design, the results imply a necessary role for the
hippocampus in the object memory, irrespective of context. Also, making the task more
perceptually demanding, by requiring the mice to perform a two-dimensional to three-dimensional
association between stimuli, engaged the hippocampus. Then, in the
traditional NOR task, long and short training exploration times were imposed to
determine brain region activity for weak and strong object memory. The inactivation and
immunohistochemistry findings imply weak object memory is perirhinal cortex
dependent, while strong object memory is hippocampal-dependent. Taken together, the
findings suggest that mice, like humans, process object memory on a continuum from
weak to strong, recruiting the hippocampus conditionally for strong familiarity.
Confirming this functional similarity between the rodent and human object memory
systems could be beneficial for future studies investigating memory disorders. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
| Identifer | oai:union.ndltd.org:fau.edu/oai:fau.digital.flvc.org:fau_33438 |
| Contributors | Cohen, Sarah J. (author), Stackman, Robert W. (Thesis advisor), Florida Atlantic University (Degree grantor), Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences |
| Publisher | Florida Atlantic University |
| Source Sets | Florida Atlantic University |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation, Text |
| Format | 232 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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