
Sean Quirin
Assistant Professor (Research) of Psychiatry and Behavioral Sciences (Major Laboratories and Clinical & Translational Neurosciences Incubator)
Bio
Dr. Quirin's laboratory develops minimally invasive methods to explore the causal role individual neurons play in the emergence of behavior. To this end, the lab's strength is the development of techniques which manipulate light to both detect and restoratively modulate brain activity down to the single-neuron scale. His lab continues to innovate with new tools which map these functional relationships onto the molecular and anatomical architecture of the brain. Utilizing these techniques, the lab aims to characterize how ensembles of neurons coordinate to encode and communicate information throughout the brain for sensing and behavior.
Academic Appointments
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Assistant Professor (Research), Psychiatry and Behavioral Sciences
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Member, Bio-X
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Member, Wu Tsai Neurosciences Institute
Professional Education
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B.A., University of Colorado, Boulder, Astronomy/Astrophysics (2004)
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PhD, University of Colorado, Boulder, Electrical Engineering (2012)
All Publications
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Compact module for video-rate image mosaics in two-photon microscopy
OPTICS EXPRESS
2025; 33 (2): 1647-1659
Abstract
Biological applications using multiphoton microscopy increasingly seek a larger field of view while maintaining sufficient temporal sampling to observe dynamic biological processes. Multiphoton imaging also requires high numerical aperture microscope objectives to realize efficient non-linear excitation and collection of fluorescence. This combination of low-magnification and high-numerical aperture poses a challenge for system design. To address this, the use of a liquid crystal polarization grating stack is proposed here to temporally sequence through multiple fields of view. This solution pans the native field of view with minimal latency and zero inertial movement of either the microscope or biological sample. Implemented as a simple add-on unit to existing multi-photon microscopes, this device increases the total field size by 4x, covering up to 7.6mm2. Performance constraints and functional demonstration of imaging neural activity are presented.
View details for DOI 10.1364/OE.544906
View details for Web of Science ID 001422856800004
View details for PubMedID 39876333
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All-optical physiology resolves a synaptic basis for behavioral timescale plasticity.
Cell
2023
Abstract
Learning has been associated with modifications of synaptic and circuit properties, but the precise changes storing information in mammals have remained largely unclear. We combined genetically targeted voltage imaging with targeted optogenetic activation and silencing of pre- and post-synaptic neurons to study the mechanisms underlying hippocampal behavioral timescale plasticity. In mice navigating a virtual-reality environment, targeted optogenetic activation of individual CA1 cells at specific places induced stable representations of these places in the targeted cells. Optical elicitation, recording, and modulation of synaptic transmission in behaving mice revealed that activity in presynaptic CA2/3 cells was required for the induction of plasticity in CA1 and, furthermore, that during induction of these place fields in single CA1 cells, synaptic input from CA2/3 onto these same cells was potentiated. These results reveal synaptic implementation of hippocampal behavioral timescale plasticity and define a methodology to resolve synaptic plasticity during learning and memory in behaving mammals.
View details for DOI 10.1016/j.cell.2022.12.035
View details for PubMedID 36669484
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Structural basis for channel conduction in the pump-like channelrhodopsin ChRmine.
Cell
1800
Abstract
ChRmine, a recently discovered pump-like cation-conducting channelrhodopsin, exhibits puzzling properties (large photocurrents, red-shifted spectrum, and extreme light sensitivity) that have created new opportunities in optogenetics. ChRmine and its homologs function as ion channels but, by primary sequence, more closely resemble ion pump rhodopsins; mechanisms for passive channel conduction in this family have remained mysterious. Here, we present the 2.0A resolution cryo-EM structure of ChRmine, revealing architectural features atypical for channelrhodopsins: trimeric assembly, a short transmembrane-helix 3, a twisting extracellular-loop 1, large vestibules within the monomer, and an opening at the trimer interface. We applied this structure to design three proteins (rsChRmine and hsChRmine, conferring further red-shifted and high-speed properties, respectively, and frChRmine, combining faster and more red-shifted performance) suitable for fundamental neuroscience opportunities. These results illuminate the conduction and gating of pump-like channelrhodopsins and point the way toward further structure-guided creation of channelrhodopsins for applications across biology.
View details for DOI 10.1016/j.cell.2022.01.007
View details for PubMedID 35114111
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Dendritic calcium signals in rhesus macaque motor cortex drive an optical brain-computer interface.
Nature communications
2021; 12 (1): 3689
Abstract
Calcium imaging is a powerful tool for recording from large populations of neurons in vivo. Imaging in rhesus macaque motor cortex can enable the discovery of fundamental principles of motor cortical function and can inform the design of next generation brain-computer interfaces (BCIs). Surface two-photon imaging, however, cannot presently access somatic calcium signals of neurons from all layers of macaque motor cortex due to photon scattering. Here, we demonstrate an implant and imaging system capable of chronic, motion-stabilized two-photon imaging of neuronal calcium signals from macaques engaged in a motor task. By imaging apical dendrites, we achieved optical access to large populations of deep and superficial cortical neurons across dorsal premotor (PMd) and gyral primary motor (M1) cortices. Dendritic signals from individual neurons displayed tuning for different directions of arm movement. Combining several technical advances, we developed an optical BCI (oBCI) driven by these dendritic signalswhich successfully decoded movement direction online. By fusing two-photon functional imaging with CLARITY volumetric imaging, we verified that many imaged dendrites which contributed to oBCI decoding originated from layer 5 output neurons, including a putative Betz cell. This approach establishes newopportunities for studying motor control and designing BCIsvia two photon imaging.
View details for DOI 10.1038/s41467-021-23884-5
View details for PubMedID 34140486
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Optical Interrogation of Memory Related Activity Across the Rodent Default Mode Network
ELSEVIER SCIENCE INC. 2020: S207
View details for Web of Science ID 000535308200499
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Rational Engineering of XCaMPs, a Multicolor GECI Suite for In Vivo Imaging of Complex Brain Circuit Dynamics
CELL
2019; 177 (5): 1346-+
View details for DOI 10.1016/j.cell.2019.04.007
View details for Web of Science ID 000468103800024
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Interacting neural ensembles in orbitofrontal cortex for social and feeding behaviour
NATURE
2019; 565 (7741): 645-+
View details for DOI 10.1038/s41586-018-0866-8
View details for Web of Science ID 000457404000048
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Interacting neural ensembles in orbitofrontal cortex for social and feeding behaviour.
Nature
2019
Abstract
Categorically distinct basic drives (for example, for social versus feeding behaviour1-3) can exert potent influences on each other; such interactions are likely to have important adaptive consequences (such as appropriate regulation of feeding in the context of social hierarchies) and can become maladaptive (such as in clinical settings involving anorexia). It is known that neural systems regulating natural and adaptive caloric intake, and those regulating social behaviours, involve related circuitry4-7, butthe causal circuit mechanisms of these drive adjudications are not clear. Here we investigate the causal role in behaviour of cellular-resolution experience-specific neuronal populations in the orbitofrontal cortex, a major reward-processing hub thatcontains diverse activity-specific neuronal populations that respond differentially to various aspects of caloric intake8-13 and social stimuli14,15. We coupled genetically encoded activity imaging with thedevelopment and application of methods for optogenetic control of multiple individually defined cells, to both optically monitor and manipulate the activity of many orbitofrontal cortex neurons at the single-cell level in real time during rewarding experiences (caloric consumption and socialinteraction). We identified distinct populations within the orbitofrontal cortex that selectively responded to either caloric rewards or social stimuli, and found that activity of individually specified naturally feeding-responsive neurons was causally linked to increased feeding behaviour; this effect was selective as, by contrast, single-cell resolution activation of naturally social-responsive neurons inhibited feeding, and activation of neurons responsive to neither feeding nor social stimuli did not alter feeding behaviour. These results reveal the presence of potent cellular-level subnetworks within the orbitofrontal cortex that can be precisely engaged to bidirectionally control feeding behaviours subject to, for example, social influences.
View details for PubMedID 30651638
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Rational Engineering of XCaMPs, a Multicolor GECI Suite for In Vivo Imaging of Complex Brain Circuit Dynamics.
Cell
2019
Abstract
To decipher dynamic brain information processing, current genetically encoded calcium indicators (GECIs) are limited in single action potential (AP) detection speed, combinatorial spectral compatibility, and two-photon imaging depth. To address this, here, we rationally engineered a next-generation quadricolor GECI suite, XCaMPs. Single AP detection was achieved within 3-10 ms of spike onset, enabling measurements of fast-spike trains in parvalbumin (PV)-positive interneurons in the barrel cortex in vivo and recording three distinct (two inhibitory and one excitatory) ensembles during pre-motion activity in freely moving mice. In vivo paired recording of pre- and postsynaptic firing revealed spatiotemporal constraints of dendritic inhibition in layer 1 in vivo, between axons of somatostatin (SST)-positive interneurons and apical tufts dendrites of excitatory pyramidal neurons. Finally, non-invasive, subcortical imaging using red XCaMP-R uncovered somatosensation-evoked persistent activity in hippocampal CA1 neurons. Thus, the XCaMPs offer a critical enhancement of solution space in studies of complex neuronal circuit dynamics. VIDEO ABSTRACT.
View details for PubMedID 31080068
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Cortical layer-specific critical dynamics triggering perception.
Science (New York, N.Y.)
2019
Abstract
Perceptual experiences may arise from neuronal activity patterns in mammalian neocortex. We probed mouse neocortex during visual discrimination using a red-shifted channelrhodopsin (ChRmine, discovered through structure-guided genome mining) alongside multiplexed multiphoton-holography (MultiSLM), achieving control of individually-specified neurons spanning large cortical volumes with millisecond precision. Stimulating a critical number of stimulus-orientation-selective neurons drove widespread recruitment of functionally-related neurons, a process enhanced by (but not requiring) orientation-discrimination task learning. Optogenetic targeting of orientation-selective ensembles elicited correct behavioral discrimination. Cortical layer specific-dynamics were apparent, as emergent neuronal activity asymmetrically propagated from layer-2/3 to layer-5, and smaller layer-5 ensembles were as effective as larger layer-2/3 ensembles in eliciting orientation discrimination behavior. Population dynamics emerging after optogenetic stimulation both correctly predicted behavior and resembled natural neural representations of visual stimuli.
View details for DOI 10.1126/science.aaw5202
View details for PubMedID 31320556
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Calcium imaging of neural circuits with extended depth-of-field light-sheet microscopy
OPTICS LETTERS
2016; 41 (5): 855-858
Abstract
Increasing the volumetric imaging speed of light-sheet microscopy will improve its ability to detect fast changes in neural activity. Here, a system is introduced for brain-wide imaging of neural activity in the larval zebrafish by coupling structured illumination with cubic phase extended depth-of-field (EDoF) pupil encoding. This microscope enables faster light-sheet imaging and facilitates arbitrary plane scanning-removing constraints on acquisition speed, alignment tolerances, and physical motion near the sample. The usefulness of this method is demonstrated by performing multi-plane calcium imaging in the fish brain with a 416×832×160 μm field of view at 33 Hz. The optomotor response behavior of the zebrafish is monitored at high speeds, and time-locked correlations of neuronal activity are resolved across its brain.
View details for DOI 10.1364/OL.41.000855
View details for Web of Science ID 000371029100003
View details for PubMedID 26974063
View details for PubMedCentralID PMC4894304
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Simultaneous imaging of neural activity in three dimensions
FRONTIERS IN NEURAL CIRCUITS
2014; 8: 29
Abstract
We introduce a scanless optical method to image neuronal activity in three dimensions simultaneously. Using a spatial light modulator and a custom-designed phase mask, we illuminate and collect light simultaneously from different focal planes and perform calcium imaging of neuronal activity in vitro and in vivo. This method, combining structured illumination with volume projection imaging, could be used as a technological platform for brain activity mapping.
View details for DOI 10.3389/fncir.2014.00029
View details for Web of Science ID 000333832600001
View details for PubMedID 24772066
View details for PubMedCentralID PMC3982072
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The Pocketscope: a spatial light modulator based epi-fluorescence microscope for optogenetics
SPIE-INT SOC OPTICAL ENGINEERING. 2014
View details for DOI 10.1117/12.2064304
View details for Web of Science ID 000349300600019
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Instantaneous three-dimensional sensing using spatial light modulator illumination with extended depth of field imaging
OPTICS EXPRESS
2013; 21 (13): 16007-16021
Abstract
Imaging three-dimensional structures represents a major challenge for conventional microscopies. Here we describe a Spatial Light Modulator (SLM) microscope that can simultaneously address and image multiple targets in three dimensions. A wavefront coding element and computational image processing enables extended depth-of-field imaging. High-resolution, multi-site three-dimensional targeting and sensing is demonstrated in both transparent and scattering media over a depth range of 300-1,000 microns.
View details for DOI 10.1364/OE.21.016007
View details for Web of Science ID 000321288400109
View details for PubMedID 23842387
View details for PubMedCentralID PMC3971059
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Quantitative Multicolor Subdiffraction Imaging of Bacterial Protein Ultrastructures in Three Dimensions
NANO LETTERS
2013; 13 (3): 987-993
Abstract
We demonstrate quantitative multicolor three-dimensional (3D) subdiffraction imaging of the structural arrangement of fluorescent protein fusions in living Caulobacter crescentus bacteria. Given single-molecule localization precisions of 20-40 nm, a flexible locally weighted image registration algorithm is critical to accurately combine the super-resolution data with <10 nm error. Surface-relief dielectric phase masks implement a double-helix response at two wavelengths to distinguish two different fluorescent labels and to quantitatively and precisely localize them relative to each other in 3D.
View details for DOI 10.1021/nl304071h
View details for Web of Science ID 000316243800020
View details for PubMedID 23414562
View details for PubMedCentralID PMC3599789
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Depth estimation and image recovery using broadband, incoherent illumination with engineered point spread functions
APPLIED OPTICS
2013; 52 (1): A367-A376
Abstract
The use of complementary engineered point spread functions is proposed for the joint tasks of depth estimation and image recovery over an extended depth of field. A digital imaging system with a dynamically adjustable pupil is demonstrated experimentally. The implementation of a broadband, passive camera is demonstrated with a fractional ranging error of 4/10(4) at a working distance of 1 m. Once the depth and brightness information of a scene are obtained, a synthetic camera is defined and images rendered computationally to emphasize particular features such as image focusing at different depths.
View details for DOI 10.1364/AO.52.00A367
View details for Web of Science ID 000313745800041
View details for PubMedID 23292415
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Limits of 3D dipole localization and orientation estimation for single-molecule imaging: towards Green's tensor engineering
OPTICS EXPRESS
2012; 20 (24): 26667-26680
Abstract
The 3D orientation and location of individual molecules is an important marker for the local environment and the state of a molecule. Therefore dipole localization and orientation estimation is important for biological sensing and imaging. Precise dipole localization is also critical for superresolution imaging. We propose and analyze wide field microscope configurations to simultaneously measure these parameters for multiple fixed dipole emitters. Examination of the images of radiating dipoles reveals how information transfer and precise detection can be improved. We use an information theoretic analysis to quantify the performance limits of position and orientation estimation through comparison of the Cramer-Rao lower bounds in a photon limited environment. We show that bi-focal and double-helix polarization-sensitive systems are attractive candidates for simultaneously estimating the 3D dipole location and orientation.
View details for DOI 10.1364/OE.20.026667
View details for Web of Science ID 000312452800055
View details for PubMedID 23187520
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Super-resolution photon-efficient imaging by nanometric double-helix point spread function localization of emitters (SPINDLE)
OPTICS EXPRESS
2012; 20 (24): 26681-26695
Abstract
Super-resolution imaging with photo-activatable or photo-switchable probes is a promising tool in biological applications to reveal previously unresolved intra-cellular details with visible light. This field benefits from developments in the areas of molecular probes, optical systems, and computational post-processing of the data. The joint design of optics and reconstruction processes using double-helix point spread functions (DH-PSF) provides high resolution three-dimensional (3D) imaging over a long depth-of-field. We demonstrate for the first time a method integrating a Fisher information efficient DH-PSF design, a surface relief optical phase mask, and an optimal 3D localization estimator. 3D super-resolution imaging using photo-switchable dyes reveals the 3D microtubule network in mammalian cells with localization precision approaching the information theoretical limit over a depth of 1.2 µm.
View details for DOI 10.1364/OE.20.026681
View details for Web of Science ID 000312452800056
View details for PubMedID 23187521
View details for PubMedCentralID PMC3971058
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Optimal 3D single-molecule localization for superresolution microscopy with aberrations and engineered point spread functions
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2012; 109 (3): 675-679
Abstract
Photo-activation localization microscopy is a far-field superresolution imaging technique based on the localization of single molecules with subdiffraction limit precision. Known under acronyms such as PALM (photo-activated localization microscopy) or STORM (stochastic optical reconstruction microscopy), these techniques achieve superresolution by allowing only a sparse, random set of molecules to emit light at any given time and subsequently localizing each molecule with great precision. Recently, such techniques have been extended to three dimensions, opening up unprecedented possibilities to explore the structure and function of cells. Interestingly, proper engineering of the three-dimensional (3D) point spread function (PSF) through additional optics has been demonstrated to theoretically improve 3D position estimation and ultimately resolution. In this paper, an optimal 3D single-molecule localization estimator is presented in a general framework for noisy, aberrated and/or engineered PSF imaging. To find the position of each molecule, a phase-retrieval enabled maximum-likelihood estimator is implemented. This estimator is shown to be efficient, meaning it reaches the fundamental Cramer-Rao lower bound of x, y, and z localization precision. Experimental application of the phase-retrieval enabled maximum-likelihood estimator using a particular engineered PSF microscope demonstrates unmatched low-photon-count 3D wide-field single-molecule localization performance.
View details for DOI 10.1073/pnas.1109011108
View details for Web of Science ID 000299154000013
View details for PubMedID 22210112
View details for PubMedCentralID PMC3271897
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Double helix PSF engineering for computational fluorescence microscopy imaging
SPIE-INT SOC OPTICAL ENGINEERING. 2012
View details for DOI 10.1117/12.909757
View details for Web of Science ID 000302561200008
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Optimal 3D single-molecule super-resolution microscopy with engineered point spread functions
IEEE. 2012: 926-927
View details for Web of Science ID 000312384100239
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Photon efficient double-helix PSF microscopy with application to 3D photo-activation localization imaging
BIOMEDICAL OPTICS EXPRESS
2011; 2 (11): 3010-3020
Abstract
We present a double-helix point spread function (DH-PSF) based three-dimensional (3D) microscope with efficient photon collection using a phase mask fabricated by gray-level lithography. The system using the phase mask more than doubles the efficiency of current liquid crystal spatial light modulator implementations. We demonstrate the phase mask DH-PSF microscope for 3D photo-activation localization microscopy (PM-DH-PALM) over an extended axial range.
View details for DOI 10.1364/BOE.2.003010
View details for Web of Science ID 000299883500008
View details for PubMedID 22076263
View details for PubMedCentralID PMC3207371
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Double-Helix 3D Photo-activation Localization Microscopy with a Phase Mask for Efficient Photon Collection
IEEE. 2011
View details for Web of Science ID 000295612401415
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Double-helix microscopy for wide-field 3D single-molecule fluorescence imaging
IEEE. 2010
View details for Web of Science ID 000290513601018