Super-wide-field two-photon imaging with a micro-optical device moving in post-objective space

Abstract

Wide-field imaging of neural activity at a cellular resolution is a current challenge in neuroscience. To address this issue, wide-field two-photon microscopy has been developed; however, the field size is limited by the objective size. Here, we develop a micro-opto-mechanical device that rotates within the post-objective space between the objective and brain tissue. Two-photon microscopy with this device enables sub-second sequential calcium imaging of left and right mouse sensory forelimb areas 6 mm apart. When imaging the rostral and caudal motor forelimb areas (RFA and CFA) 2 mm apart, we found high pairwise correlations in spontaneous activity between RFA and CFA neurons and between an RFA neuron and its putative axons in CFA. While mice performed a sound-triggered forelimb-movement task, the population activity between RFA and CFA covaried across trials, although the field-averaged activity was similar across trials. The micro-opto-mechanical device in the post-objective space provides a novel and flexible design to clarify the correlation structure between distant brain areas at subcellular and population levels.

NINscope: a versatile miniscope for multi-region circuit investigations

“…Cellular resolution imaging using miniaturized fluorescence microscopes (miniscopes) permits the monitoring of the topology of activity in brain circuits during unrestrained behaviors. While advances in electrophysiology now enable recordings from many thousands of neurons at once in awake animals (Juavinett, Bekheet, and Churchland 2018;Jun et al 2017) , imaging approaches can sample the activity of individual neurons and retain information about how their activity is spatially distributed in a large network (Terada et al 2018;Stirman et al 2016;Kim et al 2016) . Often an anatomical substrate exists for clustered activity such as is the case in the cerebellum, where nearby Purkinje cells receive input from climbing fibers originating in adjacent neurons of the inferior olive brainstem nucleus (Ruigrok 2010) .…”

Crossed-beam pump-probe microscopy

“…the post-objective space [8]; 2) accept the large size objective lens [9][10][11]; or 3) utilize multiple objective lenses [12]. While these methods have demonstrated large imaging areas (FOV >3 × 3 ) with decent resolution, they all have limitations.…”

FLAME: Macroscopic imaging with microscopic resolution. Optical biopsy of human skin

“…Enhancing imaging speed is required in order to improve the efficiency of the imaging procedure, minimizes motion artifacts and optimizes clinical work-flow. The scientific research community employing TPEF imaging for neuroscience applications has been particularly interested in imaging large tissue areas 14,15 at high scanning speed [16][17][18] . Recently, these efforts have led to the development of a two-photon mesoscope, which can produce large field-of-view images acquired relatively fast at sub-cellular resolution 19 .…”