Laserglow Technologies has developed the Cyanea™ Series of Collimated Diode Lasers that are tuned to emit low optical noise, low duty cycle and clean pulse shapes in the 470 nm spectral range, which coincides with the peak excitation wavelength for Channelrhodopsin-2 (ChR2).
The research techniques using optogenetics currently spans a broad selection of scientific disciplines including psychology, physiology, neurology and cell studies, enabled by laser technology. The multidisciplinary nature of optogenetics presents unique challenges to researchers in order to correctly determine the light activated media, an appropriate light source and accessories such as fiber optic components in order to reach the desired results in their experiments. In order to meet the requirements of the neuroscience community, Laserglow has developed a collimated diode system in the spectral range that supports the most popular light-activated opsin, Channelrhodopsin, where the temporal and spatial controls are significantly improved from the original DPSS 473 nm model. The new Cyanea™ series has inherently low optical noise, modulates very clean and swift, as well as allows complete control over the beam parameters including very low duty cycles (due to the fast rise/fall times emitted directly from the diode).
Optogenetics methods allow targeting of specific neuronal populations to trigger specific cellular behaviour using light-based stimulation. The light-sensitivity of neurons depends on the presence of light-sensitive proteins (known as opsins) impinged upon the target cells. Opsins are available in two varieties; stimulating versus inhibitory. A sub-class of opsins have been developed which have both functions available, depending on light wavelength (SFO - Step Function Opsins). Stimulating opsins open up an ion channel in the neuron causing it to 'fire', whereas inhibitory opsins (such a halorhodopsin) close or 'switch off' cell activity. Many opsins used to switch on cell activity have their peak sensitivity at 470 nm. This spectral region is where the new Cyanea™ Series from Laserglow emits. Not only because of the spectral response but also the multiple levels of control over the emission makes the new Cyanea™ LRD-470 from Laserglow a revolutionary breakthrough in pulse shape control, as well as temporal flexibility. Cyanea™ is the best Channelrhodopsin light source on the market.
The Cyanea™ series presents all the advantages of a robust collimated diode laser system, including excellent stability, excellent signal response (sine or square waveform) and superior fiber coupling efficiency. The compact unit offers sustained, durable operation, and the low optical noise is ideal for ePhys (electro-physiological) investigation. The narrow spectral band prevents cross talk with other opsins, and proximity to the peak Channelrhodopsin activation wavelength allows power control to avoid the possibility of heating the tissue by enabling use of appropriately low optical power. This emission power control and predictability ties in with one of the challenges that researchers face in optogenetics experiments - the ability to expose a portion of the brain to enough light to achieve the desired effect, without having to over-power the site and cause thermal damage (heating of the adjacent tissue). For experiments that demand multiple site stimulation the Cyanea™ series is also available in much higher power, with equal control over the device. Whether it be for controlled multiple subject, or multiple site stimulation this series offers enough optical power to support in excess of ten (10) simultaneous setups from one laser source. This limits the number of required lasers and provides improved comparative control over a group of subjects or subject neuronal populations.
The Cyanea™ series joins the other Laserglow optogenetics laser systems collection, which stretch from Ultraviolet (UV) through the visible spectrum (VIS), to Near Infrared (NIR). Our team are always excited to collaborate with the research community when developing new products to advance the use of lasers in biotechnology applications.
Optogenetics Inhibits Spontaneous, but not Odor-related Sensory Neuron Firing
Laserglow's 473 nm LabSpec™ laser was used as the light source in the experimental setup for researchers at the Champalimaud Centre for the Unknown in Lisbon, Portugal who, in collaboration with a team at the Hungarian Academy of Sciences, have published a study that investigates the effect of serotonin on neuron activity in the olfactory cortex.
Spontaneous activity is brain signaling in the absence of an explicit task, such as sensory input or motor output, and is also referred to as a 'resting-state' activity. Spontaneous activity is usually considered to be 'noise' if the study is focused on stimulus processing, however it provides much information regarding the current state of the brain (e.g. wakefulness, alertness) and is often used in sleep research.
Serotonin (known as 5-HT) impacts a wide variety of physiological functions including mood, behavior and perception, however its precise role is unknown. 5-HT neurons in the dorsal raphe nucleus (DRN) often fire due to sensory stimuli, but little is known about how 5-HT affects sensory processing. In this study, the researchers used an optogenetic approach to study the effect of 5-HT on single-unit activity in the subject's olfactory cortex. The investigators conducted an in-vivo study on a subject expressing ChR2 in the DRN 5-HT neurons and used blue laser light to activate them. This demonstrated that activation of neurons containing DRN 5-HT to rapidly inhibit spontaneous firing of olfactory cortical neurons, and entirely spare sensory-driven neuron firing.
The researchers believe that these results identify a new role for serotonergic modulation in rapidly changing the balance between different sources of neural activity (i.e. spontaneous or stimulated) in sensory systems. To learn more about the experimental setup and for a detailed discussion of the result, read the published paper at: Journal of Neuroscience Full Paper
Lasers Reveal Ancient Hidden Cities in Cambodia
Cutting-edge, airborne laser scanning technology based on LIDAR (Light Detection and Ranging) has enabled the discovery of a previously unknown, ancient temple site in Cambodia, not far from Angkor Wat. The findings are poised to upend long-standing assumptions about South-east Asia's history.
The discovery has revealed multiple cities between 900 and 1,400 years old beneath the tropical forest floor, some of which rival the size of Cambodia's capital, Phnom Penh. Some experts believe that the collective size of the cities indicates that they were densely populated and would have constituted the largest empire on earth at the time of its peak in the 12th century. The survey has uncovered an array of discoveries, including elaborate water systems. The findings are expected to challenge theories on how the Khmer empire developed, dominated the region, and declined around the 15th century, and the role of climate change and water management in that process.
The LIDAR setup includes an airborne laser scanner (ALS) mounted to a helicopter skid pad. Flying with predetermined guidelines, including altitude, flight path and airspeed, the ALS pulses the terrain with more than 16 laser beams per square meter during flights. The time the laser pulse takes to return to the sensor determines the elevation of each individual data point. The data downloaded from the ALS is calibrated and creates a 3D model of the information captured during the flights. Read more at:
The Guardian full article