Holistic bursting cells store long-term memory in auditory cortex.

The sensory neocortex has been suggested to be a substrate for long-term memory storage, yet which exact single cells could be specific candidates underlying such long-term memory storage remained neither known nor visible for over a century. Here, using a combination of day-by-day two-photon Ca imaging and targeted single-cell loose-patch recording in an auditory associative learning paradigm with composite sounds in male mice, we reveal sparsely distributed neurons in layer 2/3 of auditory cortex emerged step-wise from quiescence into bursting mode, which then invariably expressed holistic information of the learned composite sounds, referred to as holistic bursting (HB) cells. Notably, it was not shuffled populations but the same sparse HB cells that embodied the behavioral relevance of the learned composite sounds, pinpointing HB cells as physiologically-defined single-cell candidates of an engram underlying long-term memory storage in auditory cortex.

Autofluorescence spectral analysis for detecting urinary stone composition in emulated intraoperative ambient.

The prevalence and disease burden of urolithiasis has increased substantially worldwide in the last decade, and intraluminal holmium laser lithotripsy has become the primary treatment method. However, inappropriate laser energy settings increase the risk of perioperative complications, largely due to the lack of intraoperative information on the stone composition, which determines the stone melting point. To address this issue, we developed a fiber-based fluorescence spectrometry method that detects and classifies the autofluorescence spectral fingerprints of urinary stones into three categories: calcium oxalate, uric acid, and struvite.

Rabies virus-based labeling of layer 6 corticothalamic neurons for two-photon imaging .

Neocortical layer 6 (L6) is less understood than other more superficial layers, largely owing to limitations of performing high-resolution investigations . Here, we show that labeling with the Challenge Virus Standard (CVS) rabies virus strain enables high-quality imaging of L6 neurons by conventional two-photon microscopes. CVS virus injection into the medial geniculate body can selectively label L6 neurons in the auditory cortex.

Ten-kilohertz two-photon microscopy imaging of single-cell dendritic activity and hemodynamics .

Significance: The studying of rapid neuronal signaling across large spatial scales in intact, living brains requires both high temporal resolution and versatility of the measurement device.

Aim: We introduce a high-speed two-photon microscope based on a custom-built acousto-optic deflector (AOD). This microscope has a maximum line scan frequency of 400 kHz and a maximum frame rate of 10,000 frames per second (fps) at .

A corticostriatal projection for sound-evoked and anticipatory motor behavior following temporal expectation.

The ability to form predictions based on recent sensory experience is essential for behavioral adaptation to our ever-changing environment. Predictive encoding represented by neuronal activity has been observed in sensory cortex, but how this neuronal activity is transformed into anticipatory motor behavior remains unclear. Fiber photometry to investigate a corticostriatal projection from the auditory cortex to the posterior striatum during an auditory paradigm in mice, and pharmacological experiments in a task that induces a temporal expectation of upcoming sensory stimuli.

Astrocytes exhibit diverse Ca changes at subcellular domains during brain aging.

Astrocytic Ca transients are essential for astrocyte integration into neural circuits. These Ca transients are primarily sequestered in subcellular domains, including primary branches, branchlets and leaflets, and endfeet. In previous studies, it suggests that aging causes functional defects in astrocytes.

Ultra-bright carbon quantum dots for rapid cell staining.

Cellular imaging using carbon dots is an important research method in several fields. Herein, green-emissive carbon quantum dots (G-CDs) with a pretty high absolute quantum yield (QY) were fabricated a one-step solvothermal method by using -phenylenediamine and concentrated hydrochloric acid. G-CDs displayed strong green fluorescence with excitation/emission peaks at 460/500 nm, and their absolute quantum yield was as high as 58.

Brain-wide projection reconstruction of single functionally defined neurons.

Reconstructing axonal projections of single neurons at the whole-brain level is currently a converging goal of the neuroscience community that is fundamental for understanding the logic of information flow in the brain. Thousands of single neurons from different brain regions have recently been morphologically reconstructed, but the corresponding physiological functional features of these reconstructed neurons are unclear. By combining two-photon Ca imaging with targeted single-cell plasmid electroporation, we reconstruct the brain-wide morphologies of single neurons that are defined by a sound-evoked response map in the auditory cortices (AUDs) of awake mice.

High energy (>40 nJ), sub-100 fs, 950 nm laser for two-photon microscopy.

Compact and high-energy femtosecond fiber lasers operating around 900-950 nm are desirable for multiphoton microscopy. Here, we demonstrate a >40 nJ, sub-100 fs, wavelength-tunable ultrafast laser system based on chirped pulse amplification (CPA) in thulium-doped fiber and second-harmonic generation (SHG) technology. Through effective control of the nonlinear effect in the CPA process, we have obtained 92-fs pulses at 1903 nm with an average power of 0.

MATRIEX imaging: multiarea two-photon real-time in vivo explorer.

Two-photon laser scanning microscopy has been extensively applied to study in vivo neuronal activity at cellular and subcellular resolutions in mammalian brains. However, the extent of such studies is typically confined to a single functional region of the brain. Here, we demonstrate a novel technique, termed the multiarea two-photon real-time in vivo explorer (MATRIEX), that allows the user to target multiple functional brain regions distributed within a zone of up to 12 mm in diameter, each with a field of view (FOV) of ~200 μm in diameter, thus performing two-photon Ca imaging with single-cell resolution in all of the regions simultaneously.

Monitoring the Oxygen Dynamics of Brain Tissue In Vivo by Fast Acousto-Optic Scanning Microscopy: A Proposed Instrument.

The function of the brain neural circuit is highly dependent on oxygen supply. Imaging the precise oxygen distribution and dynamics are critical for understanding the relationship between neuronal activity and oxygen dynamics of the nearby capillaries. Here, we develop fast acousto-optic scanning two-photon microscopy.

Compensation of spatial dispersion of an acousto-optic deflector with a special Keplerian telescope.

Compensation of spatial dispersion caused by the acousto-optic deflector (AOD) when using a femtosecond laser is difficult across the whole scanning range of the system, and this is a significant impediment to its use. In conventional methods, the dispersion of the AOD was compensated only when it was at a particular position, while at other positions, the quality of the light beam was reduced. We developed a novel method for compensating the spatial dispersion within the entire scanning range using a special Keplerian telescope.

Beam deformation within an acousto-optic lens.

The acousto-optic lens (AOL) is becoming a popular tool in the neuroscience field. Here we analyzed the deformation of the diffraction beam after passage through an AOL consisting of a pair of acousto-optic deflectors using both theoretical and experimental data. The results showed that, because of the high sensitivity of optical spatial frequencies of acousto-optic deflectors, the boundary strength of the diffraction beam of the AOL decreases significantly.

Chemical reactivation of quenched fluorescent protein molecules enables resin-embedded fluorescence microimaging.

Resin embedding is a well-established technique to prepare biological specimens for microscopic imaging. However, it is not compatible with modern green-fluorescent protein (GFP) fluorescent-labelling technique because it significantly quenches the fluorescence of GFP and its variants. Previous empirical optimization efforts are good for thin tissue but not successful on macroscopic tissue blocks as the quenching mechanism remains uncertain.

Visualization of brain circuits using two-photon fluorescence micro-optical sectioning tomography.

Neural circuits are fundamental for brain functions. However, obtaining long range continuous projections of neurons in the entire brain is still challenging. Here a two-photon fluorescence micro-optical sectioning tomography (2p-fMOST) method is developed for high-throughput, high-resolution visualization of the brain circuits.

Fluorescence holography with improved signal-to-noise ratio by near image plane recording.

Holographic fluorescence imaging is very promising, as it can obtain three-dimensional fluorescence imaging without scanning. However, the current method usually records holograms far from the image plane, with the fluorescence decaying when spreading broadly. Here we show that the signal-to-noise ratio (SNR) of fluorescence holography can be improved by recording the high-contrast interferogram near the image plane.

Wide-band acousto-optic deflectors for large field of view two-photon microscope.

Acousto-optic deflector (AOD) is an attractive scanner for two-photon microscopy because it can provide fast and versatile laser scanning and does not involve any mechanical movements. However, due to the small scan range of available AOD, the field of view (FOV) of the AOD-based microscope is typically smaller than that of the conventional galvanometer-based microscope. Here, we developed a novel wide-band AOD to enlarge the scan angle.

Spatial and temporal thermal analysis of acousto-optic deflectors using finite element analysis model.

Thermal effects greatly influence the optical properties of the acousto-optic deflectors (AODs). Thermal analysis plays an important role in modern AOD design. However, the lack of an effective method of analysis limits the prediction in the thermal performance.