Professional Education


  • Bachelor of Arts, Harvard University (2012)
  • Doctor of Philosophy, University of California San Francisco (2019)

Stanford Advisors


All Publications


  • Are We There Yet? Identification of Reward-Selective Cells in the Hippocampus. Neuron Sosa, M., Frank, L. M. 2018; 99 (1): 7–10

    Abstract

    Navigation to a previously visited reward site requires a reliable and accurate spatial memory. In this issue of Neuron, Gauthier and Tank (2018) use two-photon calcium imaging to uncover a discrete hippocampal subpopulation specialized for encoding reward location.

    View details for DOI 10.1016/j.neuron.2018.06.037

    View details for PubMedID 30001513

  • Distinct hippocampal-cortical memory representations for experiences associated with movement versus immobility. eLife Yu, J. Y., Kay, K., Liu, D. F., Grossrubatscher, I., Loback, A., Sosa, M., Chung, J. E., Karlsson, M. P., Larkin, M. C., Frank, L. M. 2017; 6

    Abstract

    While ongoing experience proceeds continuously, memories of past experience are often recalled as episodes with defined beginnings and ends. The neural mechanisms that lead to the formation of discrete episodes from the stream of neural activity patterns representing ongoing experience are unknown. To investigate these mechanisms, we recorded neural activity in the rat hippocampus and prefrontal cortex, structures critical for memory processes. We show that during spatial navigation, hippocampal CA1 place cells maintain a continuous spatial representation across different states of motion (movement and immobility). In contrast, during sharp-wave ripples (SWRs), when representations of experience are transiently reactivated from memory, movement- and immobility-associated activity patterns are most often reactivated separately. Concurrently, distinct hippocampal reactivations of movement- or immobility-associated representations are accompanied by distinct modulation patterns in prefrontal cortex. These findings demonstrate a continuous representation of ongoing experience can be separated into independently reactivated memory representations.

    View details for DOI 10.7554/eLife.27621

    View details for PubMedID 28826483

    View details for PubMedCentralID PMC5576488

  • A hippocampal network for spatial coding during immobility and sleep. Nature Kay, K., Sosa, M., Chung, J. E., Karlsson, M. P., Larkin, M. C., Frank, L. M. 2016; 531 (7593): 185–90

    Abstract

    How does an animal know where it is when it stops moving? Hippocampal place cells fire at discrete locations as subjects traverse space, thereby providing an explicit neural code for current location during locomotion. In contrast, during awake immobility, the hippocampus is thought to be dominated by neural firing representing past and possible future experience. The question of whether and how the hippocampus constructs a representation of current location in the absence of locomotion has been unresolved. Here we report that a distinct population of hippocampal neurons, located in the CA2 subregion, signals current location during immobility, and does so in association with a previously unidentified hippocampus-wide network pattern. In addition, signalling of location persists into brief periods of desynchronization prevalent in slow-wave sleep. The hippocampus thus generates a distinct representation of current location during immobility, pointing to mnemonic processing specific to experience occurring in the absence of locomotion.

    View details for DOI 10.1038/nature17144

    View details for PubMedID 26934224

    View details for PubMedCentralID PMC5037107

  • Neural Activity Patterns Underlying Spatial Coding in the Hippocampus Behavioral Neuroscience of Learning and Memory Sosa, M., Gillespie, A. K., Frank, L. M. edited by Clark, R. E., Martin, S. J. Springer. 2016: 43–100