Systems and methods for optogenetic imaging
Systems and methods configured for simultaneous imaging and stimulation using a microscope system. The microscope system can have a relatively small size compared to an average microscope system. The microscope can comprise in part an imaging light source and a stimulation light source. Light from the imaging light source and the stimulation light source can be spectrally separated to reduce cross talk between the stimulation light and the imaging light.
1 . A microscope system configured to simultaneously image and stimulate internal tissue within a biological subject, the microscope system comprising:
an optical assembly that includes:
an illumination optical arm of the microscope system comprising one or more illumination light-emitting elements and configured to direct imaging light to said internal tissue within a specified field-of-view (FOV); and
a stimulation optical arm of the microscope system comprising one or more stimulation light-emitting elements and configured to direct stimulation light to said internal tissue within the specified FOV;
and
a housing dimensioned to house the optical assembly, the housing having a biocompatible outer surface;
wherein said optical assembly is configured to generate images of said internal tissue over the volume defined by the FOV of at least 1 mm-by-1 mm and a depth of field of at least 300 microns without loss of spatial resolution and to be at least partially implanted within said biological subject in operation of the microscope system.
2 . A microscope system according to claim 1 , configured to be carried and moved by the biological subject while said optical system is at least partially implanted within the biological subject, the biological subject being a freely behaving subject.
3 . A microscope system according to claim 1 , further comprising a baseplate that is configured to be mounted on the biological subject and to remain mounted on the biological subject in a fixed position while carried and moved by said biological subject, the biological subject being a freely behaving subject.
4 . A microscope system according to claim 3 , wherein the housing is configured to be reversibly attachable to said baseplate to align the optical assembly with respect to the internal tissue and to remain aligned with respect to the internal tissue of said freely behaving subject upon an attachment of the housing to the baseplate.
5 . A microscope system according to claim 1 , wherein the optical assembly further comprises an imaging optical arm of the microscope system, wherein the imaging optical arm includes an image sensor and is configured to receive light reflected, scattered, or emitted by said internal tissue to generate an image of the internal tissue within the specified FOV.
6 . A microscope system according to claim 5 , further comprising an adjustable lens optically shared by the illumination optical arm, the stimulation optical arm, and the imaging optical arm.
7 . A microscope system according to claim 6 , configured to vary a position of a focal plane of the microscope system without loss of spatial resolution of the image formed at the image sensor.
8 . A microscope system according to claim 1 , configured such that at least one of the following conditions is satisfied: (i) a distance between an objective lens of the microscope system and an image sensor of the microscope system is shorter than 5 cm, and (ii) a distance between a focal plane of the objective lens of the microscope system and an image sensor of the microscope system is shorter than 5 cm.
9 . A microscope system according to claim 1 , configured to satisfy at least one of the following conditions: (i) to have a weight lower than 4 grams, and (ii) to have a total volume smaller than 5 cm 3 to be carried and moved by the biological subject, the biological subject being a freely behaving subject.
10 . A microscope system according to claim 1 , further comprising:
a gradient index (GRIN) lens configured as an objective lens of the microscope system, and
a corrective optical element configured to compensate for an optical property of the GRIN lens.
11 . A microscope system according to claim 10 , wherein at least one of the GRIN lens and the corrective optical element is located outside of the housing while other elements of the optical assembly are located inside the housing.
12 . A microscope system according to claim 1 , further comprising a corrective optical element configured to provide a toroidal optical field in an object space.
13 . A microscope system according to claim 1 , wherein an optical assembly further comprises:
an imaging optical arm of the microscope system configured to receive light reflected, scattered, or emitted by said internal tissue to form an image of the internal tissue within the specified FOV, and
a corrective optical element that is a part of the optical arm but not a part of the illumination optical arm or a part of stimulation optical arm, said corrective optical element configured to correct chromatic aberrations in said image of the internal tissue.
14 . A microscope system according to claim 1 , wherein the optical assembly comprises an adjustable lens configured to vary an effective focal length and a depth of field of the microscope system or to correct for chromatic aberrations in an image of the internal tissue formed at an image sensor of the microscope system.
15 . A microscope system according to claim 14 , wherein the optical assembly comprises at least one of a gradient index (GRIN) lens and a corrective optical element configured to compensate for an optical property of the GRIN lens, wherein said at least one of the GRIN lens and the corrective optical element is in direct contact with or in close proximity with the adjustable lens.
16 . A microscope system according to claim 1 , configured to provide spatial resolution of an image of the internal tissue that is variable as a function of light delivered from the internal tissue to an image sensor of the microscope system.
17 . A microscope system according to claim 1 , configured to image said internal tissue onto the image sensor with a spatial resolution of better than 2 μm, when imaging said internal tissue over an entirety of the specified FOV.
18 . A microscope system according to claim 1 , further comprising a processor operably cooperated with the optical assembly and a tangible readable memory medium that comprises software-encoded instructions which, when loaded onto the processor, cause said processor:
a) to govern an operation of said one or more illumination light-emitting elements to modulate the imaging light in a time-dependent and/or spatially-dependent fashion; and/or
b) to govern an operation of said one or more stimulation light-emitting elements to modulate the stimulation light in a time-dependent and/or spatially-dependent manner; and/or
c) to adjust an effective focal length of the microscope system.
19 . A microscope system according to claim 18 , wherein said software-encoded instructions are configured to cause the processor:
to deliver said stimulation light to said internal tissue in a pattern; and/or
to alter said pattern based on a response of said internal tissue to said stimulation light; and/or
to modify the pattern based detecting an object of interest at said internal tissue within the specified FOV based on analysis of an image of said internal tissue generated at the image sensor.
20 . A method for forming an image of an internal tissue of a freely behaving subject, the method comprising:
mounting a baseplate on the freely behaving subject in a fixed position;
removably attaching the housing containing at least a portion of an optical assembly of the microscope system according to claim 1 to the baseplate to have the optical assembly at least partially implanted in the internal tissue;
delivering at least one of (i) imaging light from one or more illumination light-emitting elements through an illumination optical arm of said microscope system, and (ii) stimulation light from one or more stimulation light-emitting elements through a stimulation optical arm of said microscope system to the internal tissue; and
acquiring, at an image sensor of said microscope system, light that has been reflected, scattered, or emitted by said internal tissue to generate the image of a tissue volume defined by a field of view (FOV) of at least 1 mm by 1 mm and a depth of field of at least 300 microns without loss of spatial resolution.
21 . A method according to claim 20 , wherein said delivering and/or said acquiring includes transmitting light through an optical probe of said microscope system that is optically and/or mechanically coupled with the optical assembly.
22 . A method according to claim 20 , wherein said delivering and/or said acquiring includes transmitting light through an optical probe of said microscope system, wherein the optical probe is configured as an objective lens of the microscope system.
23 . A method according to claim 20 , wherein said delivering and/or said acquiring includes transmitting light through one or more adjustable lenses configured to adjust a corresponding focal depth of at least one of the illumination optical arm, the stimulation optical arm, and an imaging optical arm of the microscope system.
24 . A method according to claim 20 , wherein said delivering and/or said acquiring includes transmitting light through a corrective optical element configured in the imaging optical arm to achieve a spatial resolution of better than 2 μm at least when performing imaging at a center of a field-of-view of the microscope system.