Thalamic Nuclei Essay

Loss of Thalamic Nuclei for “Head Direction” Impairs Performance on Spatial Memory Tasks in Rats
Keerthi Thallapureddy
Dr. Mercedes Fernandez
NOVA Southeastern University

The purpose of this study is to investigate the effects of the removal of two nuclei, the anterior dorsal (AD) and the lateral dorsal (LD), in rats on the performance of spatial and nonspatial tasks. The reason for this investigation is to advance in the knowledge and understanding of the biological bases of navigation. The key components of navigation are the knowing of where one’s position and the direction of where one is heading. Place cells are neurons that provide the information of knowing one’s position, and it is found in the hippocampus. Head direction (HD) cells, are neurons that provide information on the direction, found in selective thalamic nuclei. In this study, the role of HD cells are studied in the selective thalamic nuclei, which are the AD and LD nuclei. The AD nucleus has been shown to play a role in serving as a source of the postsubicular signal and the LD nucleus has a connection to the hippocampal place fields. Correlations exist between the anterior thalamic nuclei HD cells orientation and the rats’ spatial responses. Furthermore, LD nucleus inactivation disrupts hippocampal place fields. After the removal AD and LD nuclei of the
Object recognition should not be affected by lesions in anterior thalamic lesions, so it is hypothesizes that the lesions in AD and LD should not affect the rats’ performance in the simple object recognition task. In this test, the rats are exposed to objects placed in specific locations and take a test in which some objects change locations and others remain in the same place. It is probable that rats with lesions in AD and LD should be impaired on this tasks if AD and LD nuclei play a significant role in spatial location