It is widely accepted that the hippocampus and other medial temporal lobe structures have a critical role in many forms of learning and memory. However, little is known about the contributions of regions such as the retrosplenial cortex (RSP), which is heavily interconnected with medial temporal lobe regions. Indeed, the RSP is well positioned as an interface between the sensory neocortex, thalamus, and medial temporal lobe structures. One theory is that RSP serves to integrate sensory and limbic information for subsequent mnemonic processing by medial temporal lobe regions. Another theory is that RSP is a site of long term storage of information processed by the medial temporal lobe. The proposed studies will test specific hypotheses concerning the contribution of RSP to the medial temporal lobe memory system using a combination of experimental lesion, neural activation, and learning-theoretical approaches. The resulting data will not only provide new insight into the function of RSP but also add to our understanding of the basic mechanisms of information processing in cortico-hippocampal circuits. Moreover, the data will be useful for determining how different components of these circuits interact, and aid in the development of new models of cortico-hippocampal function. Carrying out the proposed studies will also provide valuable research training and opportunities for undergraduates at Dartmouth College, and use new initiatives to promote science education and research training particularly in groups that are typically underrepresented in the sciences. At a community level, research findings will also be used to expose the local community to basic research in learning and memory through an outreach program developed in collaboration with a local science museum.
Animals not only learn about specific events or objects, but also about the 'context' or place in which they occur. In fact, there is an extensive network of cortical brain regions that support learning about contexts, yet little is known about the individual functions of these areas or how they interact. The work completed during this funding period identified the retrosplenial cortex as a critical region involved in this form of learning. The retrosplenial cortex to this point been dramatically understudied despite it key location in this network as an interface bewteen sensory regions and memory areas. Identifying its functional contributions to memory thus ehance our understanding of information processing in a circuit that is conserved through all mammals. Importantly, a combination of techniques were used to study retrosplenial cortex during this project. These techniques include experimental lesions, assessing neural activity, and pharmacology. By including different approaches, students involved in the project where able to gain new insight and first hand experience with contemporary neuroscience methods. Indeed, many undergraduate researchers and a graduate student were involved in this work. In addition, the findings were used to offer educational activities for students at Dartmouth College as well as the greater community.
