Honors & Awards


  • Larry Katz Memorial Lecture, Cold Spring Harbor (2020)
  • Milton L. Shifman Endowed Scholarship, Marine Biological Laboratory (2019)
  • SLB Travel Award, Sculpted Light in the Brain Association (2019)
  • Harvard Brain Initiative Young Scientist Travel Award, Harvard University (2018, 2019)
  • Harvard Christensen Travel Prize, Harvard University (2018)
  • Distinction in Teaching Award, Harvard University (2016)

Boards, Advisory Committees, Professional Organizations


  • Conference Organizing Committee, Sculpted Light in the Brain (2019 - Present)

Professional Education


  • Ph.D., Harvard University (2019)
  • B.S., Peking University (2013)

Stanford Advisors


All Publications


  • All-Optical Electrophysiology Reveals the Role of Lateral Inhibition in Sensory Processing in Cortical Layer 1 CELL Fan, L. Z., Kheifets, S., Bohm, U. L., Wu, H., Piatkevich, K. D., Xie, M. E., Parot, V., Ha, Y., Evans, K. E., Boyden, E. S., Takesian, A. E., Cohen, A. E. 2020; 180 (3): 521-+

    Abstract

    Cortical layer 1 (L1) interneurons have been proposed as a hub for attentional modulation of underlying cortex, but the transformations that this circuit implements are not known. We combined genetically targeted voltage imaging with optogenetic activation and silencing to study the mechanisms underlying sensory processing in mouse barrel cortex L1. Whisker stimuli evoked precisely timed single spikes in L1 interneurons, followed by strong lateral inhibition. A mild aversive stimulus activated cholinergic inputs and evoked a bimodal distribution of spiking responses in L1. A simple conductance-based model that only contained lateral inhibition within L1 recapitulated the sensory responses and the winner-takes-all cholinergic responses, and the model correctly predicted that the network would function as a spatial and temporal high-pass filter for excitatory inputs. Our results demonstrate that all-optical electrophysiology can reveal basic principles of neural circuit function in vivo and suggest an intuitive picture for how L1 transforms sensory and modulatory inputs. VIDEO ABSTRACT.

    View details for DOI 10.1016/j.cell.2020.01.001

    View details for Web of Science ID 000512977500009

    View details for PubMedID 31978320

  • Compressed Hadamard microscopy for high-speed optically sectioned neuronal activity recordings JOURNAL OF PHYSICS D-APPLIED PHYSICS Parot, V. J., Sing-Long, C., Adam, Y., Bohm, U. L., Fan, L. Z., Farhi, S. L., Cohen, A. E. 2019; 52 (14)
  • All-optical synaptic electrophysiology probes mechanism of ketamine-induced disinhibition NATURE METHODS Fan, L. Z., Nehme, R., Adam, Y., Jung, E., Wu, H., Eggan, K., Arnold, D. B., Cohen, A. E. 2018; 15 (10): 823-+

    Abstract

    Optical assays of synaptic strength could facilitate studies of neuronal transmission and its dysregulation in disease. Here we introduce a genetic toolbox for all-optical interrogation of synaptic electrophysiology (synOptopatch) via mutually exclusive expression of a channelrhodopsin actuator and an archaerhodopsin-derived voltage indicator. Optically induced activity in the channelrhodopsin-expressing neurons generated excitatory and inhibitory postsynaptic potentials that we optically resolved in reporter-expressing neurons. We further developed a yellow spine-targeted Ca2+ indicator to localize optogenetically triggered synaptic inputs. We demonstrated synOptopatch recordings in cultured rodent neurons and in acute rodent brain slice. In synOptopatch measurements of primary rodent cultures, acute ketamine administration suppressed disynaptic inhibitory feedbacks, mimicking the effect of this drug on network function in both rodents and humans. We localized this action of ketamine to excitatory synapses onto interneurons. These results establish an in vitro all-optical model of disynaptic disinhibition, a synaptic defect hypothesized in schizophrenia-associated psychosis.

    View details for DOI 10.1038/s41592-018-0142-8

    View details for Web of Science ID 000448820100031

    View details for PubMedID 30275587

    View details for PubMedCentralID PMC6204345

  • Optical control of cell signaling by single-chain photoswitchable kinases. Science Zhou, X. X., Fan, L. Z., Li, P., Shen, K., Lin, M. Z. 2017; 355 (6327): 836-842

    Abstract

    Protein kinases transduce signals to regulate a wide array of cellular functions in eukaryotes. A generalizable method for optical control of kinases would enable fine spatiotemporal interrogation or manipulation of these various functions. We report the design and application of single-chain cofactor-free kinases with photoswitchable activity. We engineered a dimeric protein, pdDronpa, that dissociates in cyan light and reassociates in violet light. Attaching two pdDronpa domains at rationally selected locations in the kinase domain, we created the photoswitchable kinases psRaf1, psMEK1, psMEK2, and psCDK5. Using these photoswitchable kinases, we established an all-optical cell-based assay for screening inhibitors, uncovered a direct and rapid inhibitory feedback loop from ERK to MEK1, and mediated developmental changes and synaptic vesicle transport in vivo using light.

    View details for DOI 10.1126/science.aah3605

    View details for PubMedID 28232577

  • Molecular Mechanism of Disease-Associated Mutations in the Pre-M1 Helix of NMDA Receptors and Potential Rescue Pharmacology PLOS GENETICS Ogden, K. K., Chen, W., Swanger, S. A., McDaniel, M. J., Fan, L. Z., Hu, C., Tankovic, A., Kusumoto, H., Kosobucki, G. J., Schulien, A. J., Su, Z., Pecha, J., Bhattacharya, S., Petrovski, S., Cohen, A. E., Aizenman, E., Traynelis, S. F., Yuan, H. 2017; 13 (1): e1006536

    Abstract

    N-methyl-D-aspartate receptors (NMDARs), ligand-gated ionotropic glutamate receptors, play key roles in normal brain development and various neurological disorders. Here we use standing variation data from the human population to assess which protein domains within NMDAR GluN1, GluN2A and GluN2B subunits show the strongest signal for being depleted of missense variants. We find that this includes the GluN2 pre-M1 helix and linker between the agonist-binding domain (ABD) and first transmembrane domain (M1). We then evaluate the functional changes of multiple missense mutations in the NMDAR pre-M1 helix found in children with epilepsy and developmental delay. We find mutant GluN1/GluN2A receptors exhibit prolonged glutamate response time course for channels containing 1 or 2 GluN2A-P552R subunits, and a slow rise time only for receptors with 2 mutant subunits, suggesting rearrangement of one GluN2A pre-M1 helix is sufficient for rapid activation. GluN2A-P552R and analogous mutations in other GluN subunits increased the agonist potency and slowed response time course, suggesting a functionally conserved role for this residue. Although there is no detectable change in surface expression or open probability for GluN2A-P552R, the prolonged response time course for receptors that contained GluN2A-P552R increased charge transfer for synaptic-like activation, which should promote excitotoxic damage. Transfection of cultured neurons with GluN2A-P552R prolonged EPSPs, and triggered pronounced dendritic swelling in addition to excitotoxicity, which were both attenuated by memantine. These data implicate the pre-M1 region in gating, provide insight into how different subunits contribute to gating, and suggest that mutations in the pre-M1 helix can compromise neuronal health. Evaluation of FDA-approved NMDAR inhibitors on the mutant NMDAR-mediated current response and neuronal damage provides a potential clinical path to treat individuals harboring similar mutations in NMDARs.

    View details for DOI 10.1371/journal.pgen.1006536

    View details for Web of Science ID 000394147700014

    View details for PubMedID 28095420

    View details for PubMedCentralID PMC5240934

  • Optical control of biological processes by light-switchable proteins WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY Fan, L. Z., Lin, M. Z. 2015; 4 (5): 545-554

    Abstract

    Cellular processes such as proliferation, differentiation, or migration depend on precise spatiotemporal coordination of protein activities. Correspondingly, reaching a quantitative understanding of cellular behavior requires experimental approaches that enable spatial and temporal modulation of protein activity. Recently, a variety of light-sensitive protein domains have been engineered as optogenetic actuators to spatiotemporally control protein activity. In the present review, we discuss the principle of these optical control methods and examples of their applications in modulating signaling pathways. By controlling protein activity with spatiotemporal specificity, tunable dynamics, and quantitative control, light-controllable proteins promise to accelerate our understanding of cellular and organismal biology. WIREs Dev Biol 2015, 4:545-554. doi: 10.1002/wdev.188 For further resources related to this article, please visit the WIREs website.

    View details for DOI 10.1002/wdev.188

    View details for Web of Science ID 000359429900006

    View details for PubMedID 25858669

    View details for PubMedCentralID PMC4529752