What Is Quartet?

Quartet is a miniature fluorescence microscope and data collection software package optimized for neuronal calcium imaging.

Thin, cylindrical, graded-refractive-index lenses (GRIN) get implanted along with our specially designed, patent-pending focus adjustable fiber-lens connector in ANY region of the brain and spinal cord. The image below is a representative of such a connector between the GRIN lens on the bottom left and fiber optics on the top right. The coin is an American dime.

Neurescence Optical Probe

The imaging fiber bundle connects to the implanted GRIN lens to transmit the fluorescence signal from neurons to the CMOS sensor. Quartet uses FOUR optical imaging fiber bundles and comes with four such highly flexible and light weight lens connectors. Each bundle includes 18000 single fibers, each of which are 7.5micron in diameter.

After connecting the fiber to the lens, the user manually finds the best focus using a key that we provide with Quartet. The design of the connector is such that even when the fiber probe is disconnected the initially set focus remains the same. This ensures the same plane of neurons is imaged as days go by, ensuring any observed changes come from the changes in the neuronal micro-circuitry and not from focusing on a different plane of neurons. This is a capability essential for answering R&D questions about brain and spinal cord neuronal micro-circuitries.

We currently offer two types of GRIN lenses for imaging different areas of the central nervous system. In the picture below, the lens that is in the connector on the top, held by the scientist, is 0.7mm in diameter and more than 8mm long to reach any area of the brain in rodents or larger animals. The lens in the connector near the ruler is 1mm in diameter and can reach areas in the brain which are up to 2.5mm deep.

Data Collection Software

  • Live display of images on the screen
  • 20 frames per second data collection, with the possibility of going up to 140 fps in burst mode
  • Capability to synchronize with other instruments. Includes both trigger-in and trigger-out.
  • Live manual adjustment of brightness and contrast
  • Manual selection of region of interest – such as neurons – and extraction of neuronal activity
  • Control of illumination level

Software allows users to obtain and save images from the microscope. Manual selection of neurons allows extraction of neuronal activity for each chosen neuron. Each frame is time-stamped and saved in a format chosen by user.

Save trace generates a .png file displaying neuron locations
The traces are then saved in a cvs file for analysis

Minimum Computer Requirement

  • GigEthernet connection
  • Intel I5 Processor
  • 16GB RAM
  • 1TB Hard Drive

Why Quartet?

  • Simultaneous imaging of multiple regions of both the brain the and spinal cord in freely behaving animals
  • Implantation in more than one animal allows simultaneous imaging of brains of multiple animals for social studies
  • Image neurons during behavioural experiments that require animal swimming
  • Capability of implantation at any angle allows imaging hard to reach brain areas, such as the olfactory bulb
  • Light and flexible probes allow performance of delicate memory and behaviour experiments with very minimal stress to the animal
  • Specially designed light connectors allow probe-lens connection with minimal stress to the animal
  • Connector design allows for simple focus adjustment that is maintained over weeks, for the duration of the experiment
  • Design allows simultaneous imaging with EEG and fMRI
  • Long electric cables allow easy lab space management
  • Light and small microscope body allows placement of the microscope body anywhere, even hanging in mid-air (e.g. above the maze)