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Using Scientifica's SliceScope to perform a variety of neuroscience techniques
Scientifica’s SliceScope upright microscope is versatile and modular, enabling it to be used for a variety of experiments including electrophysiology, fluorescence, two-photon and three-photon imaging experiments.
Here are a variety of examples of research that have used the SliceScope for different experimental techniques to investigate a range of research questions.
1. Memory enhancement by ferulic acid ester across species
Sample: Mouse hippocampal brain slices
Technique: Differential interference contrast (DIC) during whole-cell patch-clamp recordings
Researchers in a collaborative project investigated the effects of the ferulic acid eicosyl ester from the plant Rhodiola rosea on enhancing memory. The team used Scientifica’s SliceScope to visualise and identify CA1 pyramidal cells in mouse hippocampal brain slices using DIC. Whole-cell patch-clamp recordings were then performed on the brain slices.
The ferulic acid eicosyl ester was found to increase excitability in mouse hippocampal CA1 neurons and increased memory scores in older mice. The results suggest derivatives from the Rhodiola rosea could have clinical applications in treating/preventing memory loss.
2. Two-Photon Holographic Stimulation of ReaChR
Sample: Chinese Hamster Ovary cells
Scientists investigated two-photon stimulation of ReaChR, the red-shifted opsin, for the first time. The researchers, from Paris Descartes University, INSERM and the Allen Institute for Brain Science, characterised the two-photon absorption spectrum and activation kinetics of ReaChR in cultured Chinese hamster ovary cells and mouse brain slices.
The team used widefield fluorescence microscopy and oblique illumination on Scientifica’s SliceScope to visualise the morphology and location of cells in brain slices. Scientifica’s SliceScope was also used for two-photon holographic stimulation. This was achieved by imaging an SLM through an afocal telescope at the back focal plane of a water-immersion objective mounted to the SliceScope.
Both the cultured cells and brain slices were visualised under the Scientifica SliceScope using infrared illumination during patch clamp recordings.
The results found that ReaChR is sensitive to two-photon activation and is able to control action potential generation with millisecond precision at low levels of illumination, even though it has slow activation kinetics. There is therefore potential for ReaChR to be used for in vitro and in vivo optogenetic stimulation.
3. Learning-Related Plasticity in Dendrite-Targeting Layer 1 Interneurons
Sample: Mouse coronal brain slices from the auditory cortex
Technique: Differential interference contrast (DIC)
Researchers at the Max Planck Institute for Brain Research have investigated how sensory inputs are encoded in the neocortex. They specifically looked at neocortical layer 1 and used Neuron-Derived Neurotrophic Factor (NDNF) as a marker for layer 1 interneurons they discovered in a collaboration with Weizmann Institute of Science.
The team used Scientifica’s SliceScope to visualize NDNF cells in mouse coronal brain slices from the auditory cortex, with both Differential Interference Contrast and widefield fluorescence microscopy to identify fluorescently labelled cells and then establish whole-cell voltage-clamp and current-clamp recordings.
Using channelrhodopsin-2, the authors activated NDNF interneurons by brief light pulses generated by the SliceScope LED, and were thus able to map the output connectivity of these cells for the first time.
Their results indicated that dendritic inhibition by NDNF neurons is highly experience dependent. They also suggested that salient stimuli are encoded through increased levels of distal dendritic inhibition, as well as being encoded through disinhibition.
4. Functional imaging of visual cortical layers and subplate in awake mice with optimized three-photon microscopy
Sample: Awake mice
Technique: Three-photon imaging
Researchers at the Picower Institute for Learning and Memory used Scientifica’s SliceScope and translational stages to build a custom three-photon microscope.
The three-photon system has recently been used to study evoked neuronal responses of all cortical layers as well as the subplate of the primary visual cortex (V1) in awake mice, while mice were presented with sinusoidal visual gratings. Read more about this research in this case study.
5. Multiphoton minimal inertia scanning for fast acquisition of neural activity signals
Sample: Mouse hippocampal brain slices
Researchers led by Professor Simon Schultz at Imperial College London developed a new scanning algorithm that produces minimal inertia trajectories. The algorithm is named the adaptive spiral scanning (SSA) and the researchers found that this is an easily implementable way for multiphoton laser scanning systems to detect action potentials with high temporal precision, while scanning hundreds of cells.
The team used a Scientifica multiphoton system consisting of a SliceScope upright microscope with a multiphoton resonant scanhead and multiphoton detection unit. Scan paths for the multiphoton system were generated in MatLab and uploaded into SciScan which controlled the multiphoton system.
6. Tailoring light delivery for optogenetics by modal demultiplexing in tapered optical fibers
Sample: Mouse coronal brain slices
Tapered Optical Fibers enable light to be delivered to the living brain with reduced invasiveness and under tight spatiotemporal control. Unlike common light delivery methods in optogenetics, Tapered Optical Fibers can deliver light to regions deeper than 1mm without being highly invasive. Previously these researchers, in a collaborative framework between the Center for Biomolecular Nanotechnologies of the Italian Institute of Technology (Lecce, Italy) and Harvard Medical School (Boston), developed a thin Tapered Optical Fiber that could administer light to brain regions more than 1.8mm deep in the dorso-ventral direction.
Here, the researchers analysed the use of high-numerical aperture (NA) fibers to obtain wide volume or spatially-selective light delivery over 3mm, which can cover entire brain regions of several animal models. The results give quantitative data on Tapered Optical Fibers as light delivery tools which can be used to design future optogenetics experiments using a range of opsins in multiple brain regions.
A Scientifica SliceScope was used to detect fluorescence emission and capture fluorescence images in this research.
7. Marked bias towards spontaneous synaptic inhibition distinguishes non-adapting from adapting layer 5 pyramidal neurons in the barrel cortex
Sample: Coronal brain slices from mice
Technique: Patch-clamp and Dodt gradient contrast
Researchers investigated whether pyramidal neuron subtypes receive a different frequency and different balance of excitatory and inhibitory inputs. This is to increase our understanding of how different subtypes participate in information processing and how they are affected by various diseases. The team investigated the synaptic inputs of pyramidal neurons in neocortical layer 5, which have two main subtypes: adapting/thin tufted and non-adapting/thick tufted.
Pyramidal cells expressing GFP in mouse coronal brain slices were visualised and whole-cell patch-clamp recordings were carried out using Dodt Gradient Contrast on a SliceScope. Recordings were made using a Molecular Devices Multiclamp 700B amplifier and a Digidata 1550 digitizer.
The recordings showed that adapting and non-adapting neurons received significantly different levels of excitatory and inhibitory synaptic inputs. A comparable reduction in levels of inhibition in adapting and non-adapting cells would result in more unbalanced excitatory input in adapting cells, and a comparable increase in levels of inhibition in the cells would result in would result in more unbalanced inhibitory input in adapting cells. Therefore, drugs that enhance inhibitory GABAergic inputs may disrupt the balance of excitatory and inhibitory inputs of subtypes of layer 5 pyramidal neurons differently.
8. Mapping functional connectivity of bursting neuronal networks
Sample: Primary cultures of rat cortical neurons
Technique: Laser scanning photostimulation and calcium imaging
Components were added to the SliceScope by researchers at the College of New Jersey to enable simultaneous laser scanning photostimulation (LSPS) and calcium imaging of a large population of neurons.
The system was used to carry out LSPS of single neurons within a network while monitoring calcium responses of postsynaptic neurons. Connectivity maps of around 200 neurons and 2000 neural connections were created. Find out more about the research in this case study.
Scientifica SliceScope upright microscope
The SliceScope is a stable and compact upright microscope. The modular and versatile design make the system perfect for many different configurations including in vivo or in vitro electrophysiology, multiphoton imaging and confocal imaging.
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