Two-Photon Random Access Mesoscope Large Field of View

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Solution Overview

Problem

Current high-resolution microscopes have limited fields of view, while large field-of-view microscopes lack cellular resolution, making it difficult to image multiple brain areas simultaneously with high resolution, especially in applications like neural activity tracking and mesoscale imaging.

Innovation Solution

A two-photon random access mesoscope (2p-RAM) is designed with a field of view of over 5 mm, providing diffraction-limited resolution and high two-photon excitation efficiency, using resonant scanning and remote focusing to enable rapid scanning and axial movement of the focal point, allowing for simultaneous imaging of multiple brain regions with cellular resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the field of view is increased to image multiple brain areas, then the coverage area is improved, but the cellular resolution deteriorates

Engineering Contradiction:
Improvefield of viewVSAvoidcellular resolution
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent divides the large field of view into multiple smaller regions, each imaged with high resolution by a separate imaging channel or detector array. This segmentation allows each sub-region to maintain cellular resolution while the combined view covers multiple brain areas simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from two-dimensional scanning to three-dimensional parallel imaging by stacking multiple detector layers or using light-field microscopy techniques, enabling simultaneous capture of multiple focal planes across a large field of view with maintained resolution

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If the scanning speed is increased to track neural activity, then the time resolution is improved, but the photodamage increases

Engineering Contradiction:
Improvescanning speedVSAvoidphotodamage
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent uses resonant scanning at fixed frequencies (e.g., 30Hz, 60Hz) that match neural activity timescales, achieving fast time resolution while limiting total laser exposure duration. The periodic nature allows predictable photodamage management and enables frame-based processing

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements continuous scanning without repositioning delays, maintaining constant laser exposure only where needed. Combined with adaptive scanning that continuously updates based on detected neural activity, this minimizes unnecessary photodamage while maintaining temporal resolution

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If the numerical aperture is increased to improve resolution, then the lateral resolution is improved, but the depth of field decreases

Engineering Contradiction:
Improvelateral resolutionVSAvoiddepth of field
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent divides the imaging volume into multiple axial slices or layers, each captured with high numerical aperture for lateral resolution. By stacking these segmented depth layers, the system achieves both high lateral resolution and extended effective depth of field across the entire imaging volume

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses light-field microscopy or multi-plane imaging to capture angular and spatial information simultaneously, effectively adding a dimension that allows post-processing reconstruction of high-resolution images at multiple depths without sacrificing depth of field

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The 2p-RAM achieves high-resolution imaging over a large field of view, enabling faster scanning and reduced photodamage, with the ability to track a larger number of neurons and image entire brain structures at cellular resolution, overcoming the limitations of previous microscopes.

Implementation Method 1

a resonant scanner (e.g., with a 24 kHz line rate) can produce fast scanning over approximately 0.5 millimeters

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

slower galvanometer scanners (e.g., with a 1 kHz line rate) can provide deflection across the entire field of view of the microscope

Methodology Applied
Scientific EffectGalvanometer: Galvanometer

Implementation Method 3

high resolution two-photon microscopy (TPM)

Methodology Applied
Scientific EffectTwo-photon excitation:

Implementation Method 4

fluorescent protein sensors based on GFP and various red fluorescence proteins are excited using two-photon excitation

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 5

produces diffraction-limited performance

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP3368933B1Large field of view, high resolution microscope
Publication Date: 2024.01.03 HOWARD HUGHES MEDICAL INST
  • EP3368933B1 patent drawingFigure 1
  • EP3368933B1 patent drawingFigure 2
  • EP3368933B1 patent drawingFigure 3

AI summary

A microscope system including: a source of light; a sample objective configured for focusing the light at a focal plane within a sample; a remote focus unit configured for changing a position of the focal plane along an axis perpendicular to the focal plane; one or more optical element configured for directing the focused light to a location within the focal plane; and a detector configured for detecting light emitted from the focal plane within the sample; wherein the one or more optical element is located after the remote focus unit along a beam path of the light from the source to the sample objective, such that the changing the position of the focal plane along the axis is performed before the directing the focused light to the location within the focal plane.