Illuminating Neuroscience: The Power of Wireless Optogenetics

Illuminating Neuroscience: The Power of Wireless Optogenetics

Introduction

In the realm of neuroscience research, a groundbreaking technique has emerged known as wireless optogenetics. Wireless optogenetics is a fusion of wireless technology and light stimulation that allows for precise control and manipulation of neural activity in real time. In this blog, we will explore the remarkable applications of wireless optogenetics and its potential to advance our understanding of the brain. We will also delve into the limitations of traditional tethered systems and the numerous benefits offered by wireless optogenetic technology.

The Power of Optogenetics

Optogenetics utilizes light-sensitive opsins to precisely control and modulate specific neurons. By introducing genetically engineered opsins, researchers can manipulate neural activity with remarkable precision, enabling the study of neural circuits, brain activity, and neurological disorders.

Advancing Neurological Research

Wireless optogenetics holds promise in studying neurological disorders like Parkinson’s disease and epilepsy. With wireless technology, precise optical stimulation and neural modulation can be achieved, offering potential therapeutic approaches and novel treatment strategies.

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Understanding Brain Activity

Wireless optogenetics enables researchers to investigate neural circuits with exceptional accuracy, shedding light on the functional roles and connections between brain regions. This detailed understanding enhances our knowledge of brain function, information processing, and behavior generation.

Wireless Technology and Neurophysiology

Integration of wireless technology in optogenetics revolutionizes neurophysiology. Researchers can study neural activity and behavior in freely moving animals, acquiring real-time data for comprehensive analysis. This integration opens new avenues for studying the brain in natural contexts.

Future Directions

While wireless optogenetics has revolutionized neuroscience, ongoing efforts focus on miniaturizing wireless devices, optimizing power consumption, and developing advanced data analysis techniques. Integration with other cutting-edge technologies holds promise for unraveling the complexities of the brain.

In conclusion, wireless optogenetics with its precise control of neural activity through light stimulation transforms neuroscience research. It provides unprecedented insights into neural circuits, brain activity, and neurological disorders. By combining wireless technology and optogenetics, we are poised to unlock groundbreaking discoveries that will reshape our understanding of the brain.

Touch Panel Operant System for Neurological Deficit Research

Touch Panel Operant System for Neurological Deficit Research

1: Introduction and Background

Both visual discrimination (VD) and reversal learning (RL) in neurological studies are very important to study animals’ cognitive abilities.   

  • Reversal Learning:  

Reversal learning requires an animal to learn to discriminate two different stimuli but reverse its responses to these stimuli every time it has reached a learning criterion. Thus, different from pure discrimination experiments, reversal learning experiments require the animal to respond to stimuli flexibly, and the reversal learning performance can be taken as an illustration of the animal’s cognitive abilities. (1)

  • Visual Discrimination:

As for visual discrimination task, which is a task used extensively in the elucidation of cognitive impairment produced by lead, is a test in which the formerly correct stimulus becomes the incorrect one, and vice versa. (2)

2: Advantages of Touch Panel Operant System in Reversal Learning and Visual Discrimination

Our Touch panel operant training system has standard mazes that come with video tracking and automated data collection and analysis. It also contains several key features that make it a wise choice for rodent behavior, specifically mouse behavioral testing. The unique trapezoidal design creates a space for animals to focus more on the screen ahead during rodent behavior testing.

 

The Touch Panel operant training system contains infrared (IR) sensor technology, which locates at the top of the touchscreen, to improve the accuracy with which the system can detect touch responses from mice and rats. Unlike the touch screen technology that most of our smartphones and computer screens use, called projective capacitance, the infrared sensors inside the touch screen improve accuracy by eliminating the need for a minimum force required to generate a response. This means that even nose poke’s from mice will register a response.

TouchPanelScreen
Touch Panel Operant Chamber

In addition to improved sensitivity, our chamber was designed in a trapezoidal shape instead of a square, making it easier for the animal to focus on the screen ahead. Our touch panel chambers are compatible with in vivo electrophysiology and optogenetics techniques, as well as with miniature head-mounted microscopes. 

The system also includes software that enables users to design and run their own tasks with video tracking capabilities for automated data collection.The chambers come with our Operant TaskStudio Software package, an extremely user-friendly software platform that enables customers to design and execute their own tasks or choose from a variety of pre-programmed tasks.

operant-taskstudio

3: Example of Research

The team of Tatsuhiro Ayabe, Rena Ohya and Yasuhisa Ano used our touch panel-based operant system integrated with visual discrimination (VD) and reversal learning (RD) protocols.

During the VD task, vertical and horizontal stripes were shown on the screen as visual stimuli where vertical stripes were used as the correct response to half of the mice while horizontal stripes were used as the incorrect response to the other half of the mice (Figure 1). A trial started when the mouse touched the reward magazine. If the mouse was recorded poking at the vertical stripes (correct stimulus), it would be rewarded, and a 2-second inter-trial interval (ITI) would follow up. If the mouse poked at the horizontal stripes (incorrect stimulus), there would be no reward and a 5-second darkness would take place, followed up by a 5-second ITI. If the mouse touched the reward magazine again after each ITI, a new trial began. If the mouse failed to poke either stimulus in 30 seconds, the trial would be pruned. 60 minutes before the test session, the Iso-α-acids solution (1 mg/kg body weight) or distilled water (DW) would be administered through oval gavage. 30 minutes before the test session, scopolamine (0.8 mg/kg body weight) or saline would be intraperitoneally administered (Figure 2). Mice were expected to have a correct response rate that was above 80% (post-VD training) so that they would perform the VD test without drug treatments until that correct rate was achieved before they started performing the RD task.

                                Figure 1

Figure 2

After the treatment of scopolamine and iso-α-acid, both treated groups would perform the RD task. For the RD task, the visual stimuli were switched in the opposite order compared to the VD task, where horizontal stripes were used as the correct response and vertical stripes were used as the incorrect response. Only Iso-α-acids solution (1 mg/kg body weight) or distilled water (DW) would be administered through oval gavage 60 minutes before the test session for the RD task, and the scopolamine would not be administered to mice. DW and IAA solution was administered 17 times and scopolamine was treated 7 times in total during all experiment periods. The number of correct response changes was obtained by calculating the difference between the correct rate of each daily trial and the correct response rate of the first trial so that the efficiency of mice changing their previous memory conditions could be evaluated.

See the full publication

4. Applicable tasks for the Touch Panel Operant System

Task:Description:Measures:Useful for studying:
Visual Discrimination (VD)Subject learns that one of two shapes is the correct stimulus that results in food/liquid reward.Correct response is then changed-reversal learning (RD).

Cognitive flexibility

 

 

Neuropsychiatric disorders (Schizophrenia, Autism)

Research Example 1: β-lactolin, a whey-derived glycine―threonine―tryptophan―tyrosine lactotetrapeptide, improves prefrontal cortex-associated reversal learning in mice

Research Example 2: Hop-Derived Iso-α-Acids in Beer Improve Visual Discrimination and Reversal Learning in Mice as Assessed by a Touch Panel Operant System

Paired Associate Learning (PAL)Subject must learn and remember which of 3 objects goes in which correct spatial location. Each trial involves 2 objects, 1 in the correct place and the other incorrect. Mice must choose the correct object for reward.Hippocampal dysfunctionNeurodegenerative diseases (Alzheimers and Dementia)
Visuomotor Conditional Learning (VCL)Stimulus-response task. Subject must learn that two stimuli go with two different locations. When a stimulus is presented, the subject must respond to the location associated with specific stimulus.Motor dysfunctionMotor disorders (Parkinsons and Huntingtons disease)
5-Choice Serial Reaction Time (5CSRT)Subjects must respond to brief visual stimuli presented in 1 of 5 locations. Stimulus disappears after a set interval which requires the subject to return the location by memory.Attention span and impulsivityAnimal models of ADHD and Schizophrenia

Explore Our Touch Panel Operant System!

References:

(1): Bublitz, Alexander, et al. “Reversal of a Spatial Discrimination Task in the Common Octopus (Octopus Vulgaris).” Frontiers in Behavioral Neuroscience, vol. 15, 2021, https://doi.org/10.3389/fnbeh.2021.614523.

(2): Slikker, William, and Cheng Wang. “Chapter 31.” Handbook of Developmental Neurotoxicology, Academic Press, 1998, pp. 539–557. https://doi.org/10.1016/B978-0-12-648860-9.X5000-6

(3): Ayabe, T., Ohya, R., & Ano, Y. (2019). Hop-Derived Iso-α-Acids in Beer Improve Visual Discrimination and Reversal Learning in Mice as Assessed by a Touch Panel Operant System. Frontiers in Behavioral Neuroscience13, 67.

Use head-fixation to identify neurons associated with voluntary movements

Use head-fixation to identify neurons associated with voluntary movements

1. Head-Fixation in Neuroscience Research

Head-fixation is widely used in the field of behavioral neuroscience in awake behaving animals to better understand the cortical involvement in animal behaviors. Our understanding of topics such as associative learning, sensory perception, navigation and motor control have been greatly improved by head-fixed experimental preparations. The restraint and motion minimization of the animal’s head minimizes noise and motion artifacts often seen in freely moving studies, which allows for stimulus control studies, perturbation experiments, neural recordings and in vivo cellular imaging. It also simplifies the experimental set-up design and data analysis, allowing for chronic and long-duration studies as many systems facilitate accurate repeated alignment between the animal’s head and the restraining system.

Most recently, head-fixation has been used alongside advanced techniques such as high-density electrophysiology recordings and two-photon imaging to investigate neural circuits in vivo that would not be possible to study in freely moving subjects.

2. Limitations to Most Head-Fixation Systems

However, there are a number of limitations that need to be considered when carrying out large-scale monitoring of neuronal activity under head-fixed operant conditions.

  • Many models of head-fixation assume that head movements don’t occur when the animal is restrained. Some subtle movements of the animal’s head that cannot be easily observed or taken into consideration when doing data analysis can result in noise or artifact production. This can lead to significant confounding variables, with a misinterpretation of neural activity associated with animal behavior. Choosing the correct head-fixation instrumentation reduces the risk of confounding variables associated with involuntary head movements.
  • Measuring motor responses in rats or mice by monitoring whisker movements and licking behavior have been used in conditional behavioral tasks in the past. However, these motor movements are driven by a pathway in the brain involving automatic repetition that involves the brainstem. Identifying a reliable, measurable movement under operant learning conditions is imperative to accurately associate cortical activity with behavior.

3. Skilled Motor Movements in Operant Conditioning

Skilled motor movements are a good measure of operant learning, as rats and mice are naturally able to perform voluntary skilled motor movements using their forelimbs. Skilled movements are intentional isolated movements with specific parts of the body, which require the recruitment of different neural pathways that contain different subtypes of neurons firing with synchronicity. A number of operant learning paradigms can be studied by measuring forelimb movement response under head-restraint conditions alongside high-density electrophysiology recordings or two-photon imaging. It is important to consider the type of restraining system to use when studying voluntary forelimb movement in rodents.

4. Case Study – Microcircuitry coordination of cortical motor information in self-initiation of voluntary movements

Using the TaskForcer (O’Hara) restraining system, The Isomura* group at the University of Tokyo uncovered functional diversity of pyramidal cells and the uniformity activation of fast-­spiking interneurons across all cortical layers in the expression of trained rodent voluntary movement. Furthermore, they identified a pattern of excitatory synaptic interactions among neighboring neurons that play different roles in self-initiated voluntary forelimb movement.

Experimental Procedure

Juxtacellular and multi-unit recordings were taken from the motor cortex of 74 rats who were head-restrained and trained to repeat voluntary forelimbs movements. The juxta-­cellular recording technique was implemented as it provides accurate spike events and morphological features for a cortical or subcortical neuron. The multiunit recording technique is useful for exploring the synaptic connectivity of many neurons simultaneously while remaining blind and unbiased.

Amuza TaskForcer

A multi-­rat task-­training system was developed to simultaneously train up to six adult rats on an operant voluntary forelimb-­movement task. During the operant trials, the trainee rats quickly learned the relationship between the lever and the water reward. This led to the trainee rats casually grabbing the lever with their right forelimb for their reward instead of struggling during the restraining process. 

TaskForcer Lever

All 74 rats were successfully able to perform the operant motor task in just 8 days of training. Post training, the rats were transferred to a recording room where they were able to perform the same casual operant motor task during juxtacellular and multiunit recordings. Several distinct  patterns of neuronal firing at an electrode site in relation to the forelimb-­movement task were revealed during these multi-unit recordings.

Focus on results!

When research animals are stressed or distracted, training can slow and your results are what will suffer variability. Unlike other systems that allow rodents to essentially “run free” while attempting to perform tasks at the same time, Amuza’s TaskForcer eliminates those distractions—and their effects on your data.

Resources

*Isomura Y, Harukuni R, Takekawa T, Aizawa H, Fukai T. Microcircuitry coordination of cortical motor information in self-initiation of voluntary movements. Nat Neurosci. 2009 Dec;12(12):1586-93. doi: 10.1038/nn.2431. Epub 2009 Nov 8. PMID: 19898469.

Accurately monitor reward-oriented licking

Accurately monitor reward-oriented licking

Identifying efficient robust methods to monitor licking behavior in rodents is key to
understanding the role of reward-oriented dopaminergic neural pathways in animal behavior. By
monitoring licking behavior, researchers can better understand how rodents gauge the outcome
of a specific reward, their incentive for the reward and how they predict the reward (1).

However, licking microcircuitries in the brain are complex, and incorporate a number of different
neurons controlling different behaviors. A difficult task in recent times has been accurately
identifying the specific microcircuit associated with each specific reward-oriented lick behavior.

The mesolimbic dopamine system is involved in reward-oriented behaviours, and dopamine
antagonism in rodents has been shown to change ingestive behaviors. Pharmacology DAergic
stimulation of the NAc triggers an intense response to obtain a reward, even if a rat has
undergone extinction training (1). While ingestive behaviors include both feeding and drinking,
the exact involvement in water drinking remains unclear.

As mice respond to sensory stimuli by licking for liquid rewards, precise monitoring of licking
during these tasks provides an accessible metric of sensory-motor processing, particularly when
combined with simultaneous neural recordings or microdialysis (2). The precise timing of reward
consumption is critical to understand associations between neural activity and animal behavior.
Therefore using the right detection method as well as a reliable rodent model of dopamine
ensures that licks are monitored reliably (3).

Licking Units – Limitations to be considered

Some of the main challenges when developing and implementing lick detectors during head-restraint
microdialysis or neurophysiological experiments in mice include:

    1.  Electrical contact sensors that trigger food or water feeder to dispense can create
      electrical artifacts that are similar to neural or behavioral amplitudes and time courses,
      which can also interfere with electrophysiology recordings (4).
    2. Temporal characteristics of licking (approx 7Hz) are different from the profile of individual
      licks which are much faster. This is important if trying to determine the onset/offset of
      licks. If lick is being used to send TTL signals to other devices it can be troublesome.
    3. Mice are small, so behavior can be disturbed by equipment that is bulky and obstructs
      animal view.
    4. Head-restraining animals without proper habituation increases cortisol levels and could affect neural recordings / microdialysis. There it is important to ensure adequate training time

Contactless photo-sensors such as infrared detectors overcome these obstacles when
monitoring lick behavior and remove any electrical artifact interference from the set-up.

Fig. 1: Transgenic construction of DSI mice.

Different promoters expressed in each line of transgenic model. Tamoxifen administration used to induce activation of transgenic phenotype.
Dopaminergic synaptic vesicles are prevented from releasing neurotransmitters by v-SNARE cleaving in DSI models.

Case Study
Drinking behavior was analyzed in triple transgenic mice generated with reduced DA release and treated with a D1-like or D2-like DA receptor agonist. Triple transgenic mice were generated to secrete reduced dopamine levels in the striatum and nucleus accumbent compared to control. These triple transgenic mice made fewer licks and fewer lick bursts than control under thirsty conditions. D1 or D2/3 receptor agonists were then administered to identify the influence of dopamine receptors in altered drinking behavior.

New triple transgenic mouse line expected to exhibit partial blockade of synaptic release rather than severely impaired DA secretion seen in other dopamine-depleted mice models. The DSI mouse line enables the study of phenotypes related to DA loss and the role of DAergic neurons and the DA receptors in drinking behavior.

Fig 2: Training of mice to lick for a water reward.

(a) Scheme of the training for licking test. (b) After 2 days of water deprivation, control and DSI mice were trained to lick a water nozzle for a water reward (4 μl/lick) (RM‐ANOVA:genotype, p < .05; time, p < .01). The daily water intake was limited to 1.5 ml per day, and the body weight was maintained at the same level (Ctrl, n = 16; DSI, n = 16). *p < .05 compared to Ctrl mice. Values are shown as the means ± SEMs

Experimental set-up
The apparatus for licking training and data recording includes a water-pumping device and an infrared beam detector system which are controlled by software.

Thirsty mice showed vigorous activity when water was available, and they drank from different angles either in front of or under the water nozzle. This tendency reduced the accuracy of recording. Thus, the researchers utilized an apparatus (TaskForcer, O’Hara) that monitors neural circuits while a mouse is licking. A custom-made head plate was fixed onto a mouse’s skull with dental acrylic to reduce its head movements.

Assessed drinking behavior by analyzing licking microstructure

  • Number of licks and bursts
  • Size of bursts
  • Intraburst lick speed

A burst was defined as continuous licking (>2 licks with <0.4 s between licks).

After 2 days of water deprivation, the mouse was placed inside an acrylic tube and trained to lick for a water reward for 15 mins per day for 7 consecutive days.

Each interruption of the infrared beam counted as one lick, and the mouse was rewarded with one unit of water (4uL of water per lick).

Microdialysis was carried out using equipment supplied by Amuza Inc. to monitor levels of dopamine in the brain of both control and transgenic mice.

Fig 3: Scheme of the rat licking microstructure.

(a) The number of total licks carried out represents the extent of water drinking activity and therefore reflects the general drinking behavior. The number of bursts indicates the activation of responses and thus represents the incentive motivation triggered by reward cues. (b) DSI mice made fewer licks and bursts than the control littermates. The D1 receptor agonist ameliorated the lick number but did not increase the burst number, and the D2 receptor agonist suppressed all the measurement results from the licking test. The D1 agonist A68930 was effective only for DSI mice, but the D1 agonist SKF38393 was effective for both control and DSI mice

Results
Findings suggest that D1 receptor activity impacts drinking and may also contribute to treatment
for illnesses related to DA loss.

DSI mice avoid the infirmity and reduced food and water consumption exhibited by DA-deficient
mice.

DSI mice showed impaired motor control when given a challenging rotarod test and made fewer
licks and bursts than control mice.

One D1 receptor agonist increased the number of licks made by thirsty DSI mice.
While another increased the number of licks made by DSI and control mice.

Combine Operant Tasks and Rewards

TaskForcer is the must-have modular system for in-vivo electrophysiology and imaging. Our operant-behavior conditioning system is designed around your priorities. The only animal training system that was created to speed training, simplify configuration, and deliver consistent results to expedite your discoveries.

Resources

(1) Kao K‐C, Hisatsune T.: Differential effects of dopamine D1‐like and D2‐like receptor
agonists on water drinking behaviour under thirsty conditions in mice with reduced dopamine
secretion. Eur J Neurosci. 2019;00:1–14. Ht
References:
(2) Williams, B., Speed, A., Haider, B: A novel device for real-time measurement and
manipulation of licking behavior in head-fixed mice (2018)
(3) Clark, Nicholas McKinley.: FAST, ACCURATE, AND LOW-COST SENSING OF REWARD
CONSUMPTION AND LICK RESPONSES IN RODENTS (2018)
(4) Hayar, A., Bryant, J.L., Boughter, J.D., Heck D.H.: A low-cost solution to measure mouse
licking in an electrophysiological setup with a standard analog-to-digital converter (2008)

Using the ELG-2 Wireless EEG system to examine the role of the claustrum in cortical slow-wave activity

Using the ELG-2 Wireless EEG system to examine the role of the claustrum in cortical slow-wave activity

During sleep and quiet wakeful states, the neocortex exhibits large-scale slow-wave (SW) activity. The synchronous generation of the neocortical SWs implies the existence of an as-yet unknown spatiotemporal coordinating mechanism with long-range afferents driving inhibitory interneurons.

The Yoshihiro Yoshihara lab at the RIKEN Center for Brain Science sought to examine the role of the claustrum in this brain-wide cortical activity. In their recent report, The claustrum coordinates cortical slow-wave activity; the authors report that the claustrum is the neural network mechanism that facilitates the synchronous neocortical SWs.

To assess the role of the claustrum in this phenomenon, the authors generated a claustrum-specific Cre-expressing transgenic mouse line. The use of in vitro and in vivo techniques enabled the genetic visualization and manipulation of a subpopulation of claustral glutamatergic neurons.

Here, we address the author’s use of the ELG-2 Datalogger Wireless EEG system- a telemetry system designed to reduce the behavioral restrictions and data noise associated with the traditional telemetry systems.

Tethered EEG:
Traditional in vivo electroencephalography (EEG) experiments use a tethered system, where implanted electrodes are connected to the recording platform through a long cable. These systems, however, are plagued with issues due to the very nature of the tether. The long cables often tangle and restrict the animal, disrupting natural behavior. If the tether gets caught or the animal’s movement pulls too hard, damage to the cable or complete disconnections are possible. Damaged or frayed cables will cause data artifacts while complete disconnections will result in an abrupt end to data collection and injury to the animal.

Furthermore, tethered EEG equipment also suffers from poor signal-to-noise ratios. The tether acts as an antenna which can pick up electrical noise from AC power lines, motors, and other outside sources. These artifacts within the data complicate processing and interpretation. While Faraday cages may limit the noise from outside sources, they do not shield against the motion artifacts that are caused by movement of the tether itself.

Another issue evident in the traditional tethered EEG experiments is the limitation of animal scale-up. Additional tethers pose the threat of tangling and interfere with natural animal behavior as well as social interaction. Excessive environmental and motion artifacts are particularly evident when simultaneously recording EEGs from multiple rodents in close proximity. The use of Faraday cages inhibits the study of social interactions and ultimately takes up more physical space per animal in the laboratory. Limitations in the software and hardware systems of tethered EEG also reduce the possibilities of animal scale-up.

Wireless EEG:
The Amuza ELG-2 Datalogger Wireless EEG system enables researchers to wirelessly record EEG, electromyography (EMG), and local field potential (LFP) activity in freely moving animals. Designed to remove motion artifacts, the wireless lightweight headstage is small enough to sit on the head of an animal without disrupting natural behavior. The simple and flexible electrode design connects directly to a well-shielded headstage. Not only does this system reduce electrical noise from outside sources, but it also reduces implantation surgery time and complexity compared to the traditional PCB-based electrodes. The headstage is also easily removed and attached to the electrode implants, allowing researchers to interchange the device between animals. Since data is directly stored onto a microSD card, there is no signal interference across devices and animal scaleup is unlimited.

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Wirelessly recording EEG in freely moving animals has unlocked numerous possibilities for discoveries in sleep, seizure, and other neurological disorder research studies. This has previously been limited to tethered recording systems, which can alter animal behavior and add noise to data.

Wireless EEG eBook

The ELG-2 Datalogger Wireless EEG system is also customizable to meet the demands of the researchers and their individual experimental needs. The standard ELG-2 Datalogger Wireless EEG set is designed to record from four channels but can be altered to record from as few as two, to as many as seven. The standard set has two screws for EEG, two silver wires for EMG, and one screw for reference and ground. If you want to record LFP activity, electrode configurations can be custom made to fit your experimental needs. Furthermore, the electrode set uses a universal 1.27 mm pitch pin and socket connector, making it easy for you to create your own electrode sets. The standard sampling frequency is 100 Hz but can be increased to 200 Hz.

In the Narikiyo, K. et al study, the authors opted to use two customized ELG-2 Datalogger Wireless EEG systems to simultaneously record from two mice. The headstage was designed to record from 5-channels with a 200 Hz sampling frequency. They created their own electrode configuration to record LFPs in the neocortex and monitor sleep/wake states with EEG and EMG recordings. Their setup included three perfluoroalkoxy-coated stainless steel wires for LFP recordings, one screw for EEG, one silver wire for EMG, and one screw for ground and reference.

Experimental Design:
To assess the role of the claustrum in the synchronous generation of widespread neocortical SW activity during sleeping and awake rest states, the authors generated a claustrum-specific Cre-expressing transgenic mouse line.

Male and female mice, one to eight months of age, were used for anatomical experiments and slice physiology to determine the neural network connectivity between the claustrum and the neocortex. Male mice, two to six months of age, were used for in vivo EEG and optogenetic experiments to assess the underlying temporal relationship between the claustrum and the neocortex with respect to SW activity.

The authors performed an in vivo loss-of-function experiment with the ELG-2 Datalogger Wireless EEG system in freely moving mice to examine the necessity of the claustrum for synchronized cortical SW generation. The Cre-positive claustral neurons were selectively ablated via AAV-mediated injection of the Cre-dependent diphtheria toxin A subunit (DTA). Control mice were injected with GFP.

The ELG-2 Datalogger Wireless EEG electrodes were surgically implanted into anesthetized mice, 2 weeks after injection. The LFP wire electrodes were implanted into the deep layers of the right prefrontal cortex (coordinates: AP: 2.5–2.8, ML: 0.5–1.5, DV: 1.0–1.5), anterior cingulate cortex (coordinates: AP: 1.0, ML: 0.5, DV: 1.3), and parietal cortex (AP: −2.0, ML: 1.5, DV: 0.4). The EEG electrode and EMG wire electrode were implanted into the left parietal cortex (AP: -2.0; ML: 2.0) and neck muscle, respectively. The electrical ground and reference electrode was implanted above the cerebellum.

Recordings were performed in the home cage under a 12-hour light/12-hour dark cycle, 6 to 12 weeks after AAV injection. Mice were acclimated to the weight and presence of the headstage with a dummy device overnight before experimentation. LFPs were recorded to detect SW activity in the deep layers of the cortex. The EEG and EMG electrodes were used to monitor the behavioral states of the mice.

Results
The generation of a genetic neural circuit map of the claustrum’s input and output connectivity revealed widespread reciprocal connections between the Cre-expressing claustral glutamatergic neurons and cortical areas.

In vitro whole-cell patch clamp recordings during optogenetic stimulation demonstrated that photostimulation of claustral neurons evoked excitatory postsynaptic potentials in all types of neurons but predominantly drove spike responses in inhibitory interneurons.

In vivo EEG in head-fixed mice revealed that the claustral glutamatergic neurons were more active during SW periods as compared to non-SW, suggesting that the claustrum activity is more closely related to SW activity than it is to the sleep state. When combined with optogenetic stimulation, in vivo EEG revealed that claustrum-induced SW activity via photostimulation mirrors spontaneous SW activity and suggests that the claustrum can regulate SW generation in neocortical areas through the coordinated activation of inhibitory interneurons.

The recorded LFPs during the loss of function experiment with the ELG-2 Datalogger Wireless EEG system revealed that the claustral-neuron-ablated mice showed a dramatic attenuation of the SW activity during SW sleep and awake rest as compared to the control. The authors indicate that the results demonstrate the importance of the claustrum in the synchronous coordination of cortical SW activity.

Discussion
Through the genetic visualization and manipulation of the Cre-expressing claustral glutamatergic neurons, the authors were able to identify the claustrum as a brain structure that can serve as the spatiotemporal mechanism that generates the synchronous neocortical SW activity during sleep and awake rest.

The use of the ELG-2 Datalogger Wireless EEG system allowed the authors to wirelessly record SW activity in the neocortex while monitoring the behavioral states of mice. This system promotes the natural behavior of animals while removing the artifacts commonly associated with traditional tethered EEG experiments. The ability to accurately and efficiently record in vivo telemetry data from freely moving animals without behavioral restrictions enables reproducible data acquisition across experiments and allows future research to build upon the established findings.

Narikiyo, K., Mizuguchi, R., Ajima, A., Shiozaki, M., Hamanaka, H., Johansen, J.P., Mori, K., Yoshihara, Y. The claustrum coordinates cortical slow-wave activity. Nature Neuroscience, 2020;23(6): 741-753. doi:10.1038/s41593-020-0625-7

Amuza Wireless Neuroscience
The traditional tethered systems do not only impose barriers in EEG experiments, they also hinder natural animal behavior and produce data artifacts during in-vivo optogenetic and fiber photometry experiments. The Amuza TeleOpto and TeleFipho systems are easy to use wireless systems, designed for reproducibility and animal comfort.

O’Hara Behavioral Testing Equipment

O’Hara Behavioral Testing Equipment

Built out of a desire to help standardize behavioral neuroscience research

One of our brands O’Hara, a manufacturing company based out of Japan, has been developing and manufacturing equipment for behavioral experiments for over 40 years. O’Hara got its start by designing and manufacturing equipment for pharmaceutical companies that were doing efficacy testing on various therapeutic drugs. They quickly realized that there was no method of standardization across behavioral studies from different labs, research institutes, and pharmaceutical companies, which they felt would have detrimental consequences on data integrity. With this issue at the forefront of their minds, O’Hara began developing automated behavior tests to improve the reliability of behavioral data. This newfound focus was born out of a desire to help improve the reproducibility crisis that has been plaguing Neuroscience research for several years now – That is the inability to replicate scientific studies across experiments and research institutions.

What is the reproducibility crisis?

Reproducibility or replicability from a research standpoint is the idea that a given set of experimental findings should be able to be replicated following the same procedures. The inability to replicate basic scientific findings across research institutions and even across experiments is a major issue plaguing Neuroscience research today and is particularly prevalent in animal studies. This is not hard to believe given that the use of animals themselves provides inherent variability, even when all other factors are controlled for. To read more about this issue and what we are doing to try and alleviate the problem click here.

Ohara offers a variety of automated systems to help you standardize the data collection process

Don’t see what you are looking for?

O’Hara is committed to making customizable solutions to fit the researcher’s specific needs, and therefore our products can be tailored to better fit your needs. In fact, two of our products, the Free Maze and the Self head-Restraining Platform were created out of collaborations between research labs and O’Hara.

Learn more about the background behind the making of the Free Maze here.

Learn more about the motivation behind the Self Head-Restraining Platform here.

For more detailed information about our automated behavioral solutions connect with us today.