No description available.

Thesis (Ph. D.)--Columbia University, 1932. / Vita. Bibliography: p. 77-78.

In this thesis, I describe the use of two different techniques for the targeting and functional inactivation of individual populations of GABAergic interneurons located within the cerebellum and dentate gyrus of the hippocampus. Through functional inactivation of these interneuron types, I demonstrate their behavioural relevance for the processes of learning and memory. In chapter 2, I describe a genetic approach for the removal of GABAA-mediated signalling from molecular layer interneurons (MLIs) onto Purkinje cells within the cerebellum. Using the Cre lox P system to delete post-synaptic GABAA receptors on Purkinje cells, I have shown a previously unappreciated role for MLIs in fear memory. Deficits were specific to the acquisition and long-term retention of fear memories suggesting that feed-forward inhibition from MLIs onto Purkinje cells is critical for these processes. In chapter 3, I describe a further development to this project through the creation of a novel dual recombinase mouse line. This intersectional approach of combining Cre and Flpo recombinase systems together would allow direct targeting of MLIs for the first time and circumvent drawbacks associated with using a static genetic knockout approach. In chapter 4, I describe an adeno-associated viral (AAV) approach to target a specific population of GABAergic interneurons located within the hilar region of the dentate gyrus. These hilar perforant path-associated (HIPP) cells are characterised by their expression of the neuropeptide somatostatin (SST) and regulate granule cell activity through feedback inhibition. However, up until now their behavioural relevance has been unknown. Through Cre-mediated viral expression of tetanus toxin light chain (TeLC), neurotransmission was prevented in SST interneurons revealing an involvement in spatial working memory and spatial reference memory precision. In addition, preliminary immediate early gene data suggests that SST interneurons increase memory precision through maintaining the sparse activity of the granule cell population through feedback inhibition.

Issued also as Thesis (Ph. D.)--Columbia University. / Bibliography: p. 55-56.

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 200 . / Includes bibliographical references (leaf 161-172) Also available in print.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The fornical tract, a major input-output pathway of the hippocampus, of the primate brain makes crucial contributions to visual memory, as effects after surgical or aetiological lesions of this tract are widely documented in the monkey and human literature. Here, a series of experiments sought to further elucidate the functions of this structure with a battery of novel tasks in macaque monkeys, conducted either on a touchscreen or in an ambulatory chamber, so as to offer a more global view of the mnemonic role accomplished by it. After receiving bilateral transection of the fornix, monkeys are impeded in the 'fast learning' phase of a large number of new visuospatial conditional problems, with major impairments seen in eliminating non-perseverative errors. These fornix transected monkeys are however facilitated in the initial acquisition of a visuovisual conditional task, with facilitation seen in their improved ability in eliminating perseverative errors. It is also demonstrated in an ambulatory apparatus, in comparison to control monkeys, these monkeys are impaired in the new learning of visuospatial context of environments, albeit still displaying intact locomotor and exploratory behaviour patterns. Contrary to the relatively clear role in new learning, the involvement of the fornix in memory retention over the very long-term is unknown. It is shown here that once some visuospatial information is learnt; the fornix is no longer implicated in the retention of the material. The effects of fornix transection are also found to be detrimental on a spatial recognition task, with impairments observed in acquisition of the more demanding stages of the task. The overall results covered in this thesis support previous work suggesting that the fornix mediates the new learning of visual information, and I further propose that this fornical involvement lies primarily in the learning of spatio-temporal contexts, particularly during 'fast learning', as well as in task-sets acquisition. I also argue for dissociation in the contributions of the fornix and hippocampus to some memory processes in the macaque.

Thesis (Ed. D.)--University of La Verne, 2003. / Includes bibliographical references (leaves 184-191).