Rhythmic coordination of hippocampal neurons during associative memory processing
Lara M Rangel,
Jon W Rueckemann,
Pamela D Riviere,
Katherine R Keefe,
Blake S Porter,
Ian S Heimbuch,
Carl H Budlong,
Howard Eichenbaum
Affiliations
Lara M Rangel
Center for Memory and Brain, Boston University, Boston, United States; Cognitive Rhythms Collaborative, Boston University, Boston, United States; Bioengineering Department, University of California, San Diego, La Jolla, United States
Jon W Rueckemann
Center for Memory and Brain, Boston University, Boston, United States
Pamela D Riviere
Center for Memory and Brain, Boston University, Boston, United States
Katherine R Keefe
Center for Memory and Brain, Boston University, Boston, United States
Hippocampal oscillations are dynamic, with unique oscillatory frequencies present during different behavioral states. To examine the extent to which these oscillations reflect neuron engagement in distinct local circuit processes that are important for memory, we recorded single cell and local field potential activity from the CA1 region of the hippocampus as rats performed a context-guided odor-reward association task. We found that theta (4–12 Hz), beta (15–35 Hz), low gamma (35–55 Hz), and high gamma (65–90 Hz) frequencies exhibited dynamic amplitude profiles as rats sampled odor cues. Interneurons and principal cells exhibited unique engagement in each of the four rhythmic circuits in a manner that related to successful performance of the task. Moreover, principal cells coherent to each rhythm differentially represented task dimensions. These results demonstrate that distinct processing states arise from the engagement of rhythmically identifiable circuits, which have unique roles in organizing task-relevant processing in the hippocampus.
