Two-Photon Fluorescence Microscope Provides a Glimpse Into the Future

The Two-Photon fluorescence microscope takes humanity one step closer to being able to interact with its surroundings using only thought.

Monitoring brain activity has been a core component of neuroscience since the capability first emerged. The human brain is less understood than the universe and oceans. As such, there's a massive effort to unravel the mysteries that lie within your mind. Now, researchers can delve deeper into mental activity in real time using a revolutionary two-photon fluorescence microscope method. Here's what you need to know.

Understanding brain activity is crucial for many industries, including treating neurological diseases like Alzheimer's. Scientists have spent considerable effort unraveling how neurons communicate and interact during thought. The goal of this research is to fully understand complex neural interactions down to cellular resolution.

Researchers hope to use this data to shed light on fundamental brain functions which could one day lead to improved learning, memory, decision-making, and health care. To accomplish this task they created an advanced two-photon imaging tool capable of tracking dynamic neural processes in real-time, enabling a deeper insight into the brain during learning, activities, and disease states.

Current Methods of Registering Brain Activity

There are several methods of registering brain activity in use today. These approaches have helped the industry develop to this date. However, they do have some significant drawbacks including that they take more time to monitor activity, can be harmful to the patient, and are cost-prohibitive. The two most common methods in use today include Functional Magnetic Resonance Imaging (fMRI) and Electroencephalography (EEG).

Functional Magnetic Resonance Imaging (fMRI)

Functional Magnetic Resonance Imaging is one of the most advanced methods used to monitor brain waves today. This non-invasive procedure integrates magnetic fields and radio waves to create a 3D image of your brain's electromagnetic pulses. This strategy marked a major improvement over previous options as it allowed researchers to zoom in on a particular set of neurons, improving their overall understanding of brain activity greatly.

Electroencephalography (EEG)

Another method that you may have seen in movies is Electroencephalography. This approach measures your brain's electrical activity. Patients need to place special sensors on their scalp that are sensitive to electrical currents. This method of tracking brain waves has been used since 1975 when Richard Caton first used it to track the electrical pulses found in rabbits' and monkeys' brains with success.

Since then, this method of registering brain activity has improved significantly. In the 1950s, the first modern iteration of the EEG was introduced. It served faithfully as the primary method of tracking brain waves into the 1980s. In 1988, it was used to enable a person, to control a robot and is still used by many researchers.

Study

The study “High-speed two-photon microscopy with adaptive line-excitation” was published in Optica revealing how two-photon microscopy can provide unmatched high-speed images of neural activity. These photos were made at a cellular resolution using a purpose-built two-photon fluorescence microscope.

Two-Photon Fluorescence Microscope

The Two-Photon fluorescence microscope is capable of providing vibrant images deep into brain tissue. To accomplish this task, the mechanism introduces an adaptive sampling structure. This structure would be repeated throughout the experiment to create dynamic 3d images and maps of brain activity.

Adaptive Sampling Strategy

At the core of the study is the introduction of the adaptive sampling strategy. This method replaces traditional point illumination techniques. Instead, a more effective line illumination strategy is employed alongside an updated point scanning method that provides far more detail and monitoring capabilities compared to past methods.

Point Scanning

Point scanning in old methods left much to be desired. For one, it was extremely specific which would often lead to the inability to track an entire neuron sequence across the brain. The new point scanning method uses an altered line illumination strategy to imitate high-resolution point scanning methods. This strategy is crucial in identifying what areas of the brain need to move on to the next step of the process, line scanning.

Line Illumination

Line illumination is a breakthrough for neurology engineers. The method projects a small line of light across a sampled area. This approach excites fluorescence, which makes it easier to track neurological signals across the brain from start to finish. Additionally, this approach allows a much larger area of the brain to be excited, scanned, and mapped in real-time.

Two-Photon Microscope Testing

The testing phase of the two-photon fluorescence microscope involved two lab mice, in which researchers were able to track neuronal activity in a mouse cortex in real time. Notably, the unit can capture image signals up to 198 Hz currently. In this test, the engineers tracked calcium signals which can signal recent neural activity.

Digital Micromirror Device (DMD)

To accomplish this task, a specially configured laser beam pattern is formed using a digital micromirror device (DMD). This unit contains thousands of microscopic mirrors. Each of these mirrors has individual controls that allow them to shape and target light at precise parts of the brain. Additionally, the mirrors can be set up to activate