Spatial Strategy Selection in the Submerged T-Maze

spatial;maze;rodent;strategy;hippocampus;striatum;Neuroscience

Asem, Judith Sylvia AmaKnierim, James J. ;

Johns Hopkins University

关键词: spatial;    maze;    rodent;    strategy;    hippocampus;    striatum;    Neuroscience;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/39563/ASEM-DISSERTATION-2015.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

The ability to navigate in one’s environment is critical to survival, be it in order to acquire positive reinforcers—food, water, mates, shelter, and sleep—or to escape negative consequences—predation and pain. Spatial navigation is commonly examined using the T-maze, in which experimenters are able to dissociate two distinct strategies that are exhibited by animals when acquiring the location of a goal. The behavioral history and details of spatial navigation are introduced in Chapter 1.Chapter 2’s behavioral data reveal that the emergence and progression of these spatial strategies are different if the animal is in an appetitive versus an aversive environment. Motivated by food, rats initially use the relational information in environmental cues (a ;;place strategy”) before switching to an automatic, movement-based tactic (a ;;response strategy”). Motivated to escape a noxious stimulus, as in the submerged T-maze, rats perform the opposite pattern.Bolstered by several investigations, Chapter 3 introduces the concept of multiple memory systems, which suggests that, in the dry T-maze and Morris water maze, a place or spatial strategy is subserved by the dorsal hippocampus (HPC), whereas a stimulus-response (S-R) strategy is subserved by the dorsolateral striatum (DLS). Critically, our observation of the immediate expression of a response strategy and the gradual switch to a place strategy in the submerged T-maze initiates questions regarding the underlying neural circuitry.Chapter 4 suggests that the dorsal hippocampus is unnecessary for the expression of the late place strategy, despite the same pharmacological manipulation causing impairments in a separate task previously shown to require the region. These results are elucidated by the closer investigation of immediate early gene (IEG) expression in dorsal hippocampal subregions, and further discussed in a unifying theory of hippocampal function in Chapter 5. On the other hand, Chapter 6 proposes a necessary role of the dorsolateral striatum (DLS) in the acquisition, but not the expression, of the early response strategy, whereas Chapter 7 deliberates the broader implication of the striatum and basal ganglia. The modulatory roles of motivation and stress are purported in Chapter 8, with an emphasis on regulation by amygdalar and prefrontal regions in Chapter 9.In utilizing multiple approaches, this research represents an innovative and important step in the converging exploration of the motivational modulation of behavior, specifically that of spatial navigation. This investigation is critical for understanding the strategies undertaken by individuals in stressful circumstances, and may be most relevant for military training and the rescue of missing persons. Furthermore, the implicated neural systems are involved in a variety of diseases, including both Parkinson’s and Alzheimer’s. Using maze learning paradigms, we combine these essential issues with the well-established rodent model. Notably, a general discussion expands our knowledge regarding how motivation modulates multiple aspects of the production and maintenance of behavior.