PROJECT SUMMARY
The ability to form and store memories from experience to shape future behavior is a remarkable and
foundational cognitive capability. While many brain regions interact to enable cognitive processes of learning
and decision making, the subiculum and hippocampus of the medial temporal lobe are central nodes in the
underlying neural circuit. Accordingly, medial temporal lobe dysfunction is a hallmark of psychiatric disorders
such as depression, PTSD and other anxiety disorders, epilepsy, and Alzheimer’s disease. Understanding basic
neural function and coordination processes in the subiculum and hippocampus during memory and decision
making will therefore be crucial in the progress towards effective interventions for these disorders; however,
subiculum function and its coordination with hippocampus during these cognitive tasks is almost completely
unknown. The central hypothesis of this proposal is that subiculum links individual memories formed by the
hippocampus and thereby enables cognitive capabilities such as abstraction, categorization, and deliberation
during decision making. During the mentored phase (K99), high-density in vivo electrophysiology will be used in
rats to observe subiculum and hippocampal subregion CA1 activity during a navigational memory-guided
decision making task. Optogenetic interruption of the proposed coordination mechanism between subiculum and
CA1 during behavior will then provide evidence to its necessity for memory-guided decision making. Theoretical
models will assess plausible mechanisms underlying the formation of subiculum activity patterns. Experiments
during the independent (R00) phase will extend this approach through the dorsal-ventral extent of CA1 and
subiculum and to emotional aspects of memory such as hedonic value. Successful completion of this proposal
has the potential to result in two significant conceptual breakthroughs: 1) subiculum is a major and critical
component of hippocampal output with specific and distinct functions during memory-guided decision making,
2) subiculum and CA1 function and encoding properties are consistent throughout their dorsal-ventral extents
and are best understood under a single conceptual framework. This research plan will be executed by Dr. Jacob
Olson under the guidance of Dr. Shantanu Jadhav and Dr. Donald Katz, facilitated by the collaborative,
innovative, and rigorous nature of the Neuroscience Program and Department of Psychology at Brandeis
University. This proposal also contains a comprehensive training and development plan with emphases on
cutting-edge recoding and manipulation techniques, theoretical modeling, and scholarly development to fully
prepare Dr. Olson to lead an innovative and impactful research program studying the mechanisms of neural
coordination underlying memory-guided decision making as an independent investigator.